IPS Working Group Bernard Aboba INTERNET-DRAFT William Dixon Category: Informational Microsoft David Black 5 October 2001 EMC Joshua Tseng Nishan Systems Joseph Tardo, Uri Elzur Broadcom M. Bakke, S. Senum Cisco Systems Howard Herbert, Jesse Walker Intel J. Satran Ofer Biran Charles Kunzinger IBM Venkat Rangan Rhapsody Networks Inc. Franco Travostino Nortel Networks Securing iSCSI, iFCP and FCIP Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. Aboba, et al. Informational [Page 1] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Abstract This document discusses how iSCSI, iFCP, and FCIP may utilize IPsec to provide authentication, integrity, confidentiality and replay protection. Table of Contents 1. Introduction .......................................... 3 1.1 iSCSI overview .................................. 3 1.2 iFCP overview ................................... 3 1.3 FCIP overview ................................... 4 1.4 IPsec overview .................................. 4 1.5 Terminology ..................................... 5 1.6 Requirements language ........................... 6 2. iSCSI, iFCP and FCIP security ......................... 6 2.1 Security requirements .......................... 6 2.2 Resource constraints ............................ 9 2.3 Security protocol ............................... 10 3. iSCSI security inter-operability guidelines ........... 11 3.1 iSCSI security issues ........................... 11 3.2 iSCSI and IPsec interaction ..................... 12 3.3 Initiating a new iSCSI session .................. 13 3.4 Graceful iSCSI teardown ......................... 14 3.5 Non-graceful iSCSI teardown ..................... 15 3.6 Application layer CRC ........................... 16 4. iFCP and FCIP security issues ......................... 17 4.1 iFCP and FCIP Authentication Requirements ....... 17 4.2 iFCP Interaction with IPsec and IKE ............. 18 4.3 FCIP Interaction with IPsec and IKE ............. 19 5. Security considerations ............................... 20 5.1 Transport mode versus tunnel mode ............... 20 5.2 NAT traversal ................................... 21 5.3 IKE issues ...................................... 22 5.4 Rekeying issues ................................. 24 5.5 Transform issues ................................ 25 5.6 Fragmentation issues ............................ 27 5.7 Security checks ................................. 28 5.8 Authentication issues ........................... 29 5.9 Use of AES in counter mode ...................... 32 6. References ............................................ 32 Appendix A - Software Performance of IPsec Transforms ....... 37 A.1 Authentication transforms ....................... 37 A.2 Encryption and Authentication transforms ........ 40 Acknowledgments .............................................. 45 Authors' Addresses ........................................... 46 Intellectual property statement .............................. 48 Full Copyright Statement ..................................... 49 Aboba, et al. Informational [Page 2] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 1. Introduction This draft proposes use of the IPsec protocol suite for protecting iSCSI, iFCP and FCIP traffic over IP networks, and discusses how iSCSI, iFCP and FCIP should be used with IPsec. 1.1. iSCSI overview iSCSI, described in [1], is a connection-oriented command/response protocol that runs over TCP, and is used to access disk, tape and other devices. iSCSI is a client-server protocol in which clients (Initiators) open connections to servers (Targets) and perform an iSCSI login. This draft uses the SCSI terms Initiator and Target for clarity and to avoid the common assumption that clients have considerably less computational and memory resources than servers; the reverse is often the case for SCSI, as Targets are commonly dedicated devices of some form. The iSCSI protocol has a text based negotiation mechanism as part of its initial (Login) procedure. The mechanism is extensible in what can be negotiated (new text keys and values can be defined) and also in the number of negotiation rounds (e.g., to accommodate functionality such as challenge-response authentication). While the iSCSI login may include mutual authentication of the iSCSI endpoints and negotiation of session parameters, iSCSI does not define its own per-packet authentication, integrity, confidentiality or replay protection mechanisms. After a successful login, the iSCSI Initiator may issue SCSI commands for execution by the iSCSI Target, which returns a status response for each command, over the same connection. A single connection is used for both command/status messages as well as transfer of data and/or optional command parameters. An iSCSI session may have multiple connections, but a separate login is performed on each. The iSCSI session terminates when its last connection is closed. iSCSI Initiators and Targets are layer 5 entities that are independent of TCP ports and IP addresses. Initiators and Targets have names whose syntax is defined in [52]. iSCSI sessions between a given Initiator and Target are run over one or more TCP connections between those entities. That is, the Login process establishes an association between an iSCSI Session and the TCP connection(s) over which iSCSI PDUs will be carried. 1.2. iFCP overview iFCP, defined in [56], is a gateway-to-gateway protocol, which provides Fibre Channel fabric services to Fibre Channel devices over a TCP/IP Aboba, et al. Informational [Page 3] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 network. iFCP's primary objective is to allow interconnection and networking of existing Fibre Channel devices at wire speeds over an IP network. The protocol achieves this transparency through a process that allows normal Fibre Channel frame traffic to pass through the gateway directly, with provisions where necessary for intercepting and emulating the fabric services required by a Fibre Channel device. Each IPsec SA established by IKE protects a single TCP connection, which is used to support storage traffic between a unique pair of Fibre Channel N_PORTs. 1.3. FCIP overview FCIP, defined in [57], is a pure FC encapsulation protocol that transports FC frames. Current specification work intends this for interconnection of Fibre Channel switches over TCP/IP networks, but the protocol is not inherently limited to connecting FC switches. FCIP differs from iFCP in that no interception or emulation of fabric services is involved, and TCP connections are not bound or restricted to specific FC N_Port pairs. iFCP and FCIP do not have a native, in-band security mechanisms. Rather, they rely upon the IPsec protocol suite to provide data confidentiality and authentication services, and IKE as the key management protocol. Both FCIP and iFCP use TCP to provide congestion control, error detection and error recovery. 1.4. IPsec overview IPsec is a protocol suite which is used to secure communication at the network layer between two peers. The IPsec protocol suite is specified within the IP Security Architecture [6], IKE [7], IPsec Authentication Header (AH) [3] and IPsec Encapsulating Security Payload (ESP) [4] documents. IKE is the key management protocol while AH and ESP are used to protect IP traffic. An IPsec SA is a one-way security association, uniquely identified by the 3-tuple: SPI, protocol (ESP) and destination IP. The parameters for an IPsec security association are typically established by a key management protocol. These include the encapsulation mode, encapsulation type, session keys and SPI values. IKE is a two phase negotiation protocol based on the modular exchange of messages defined by ISAKMP [54]. IKE has two phases, and accomplishes the following functions: [1] Protected cipher suite and options negotiation - using keyed HMACs and encryption and anti-replay mechanisms Aboba, et al. Informational [Page 4] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 [2] Master key generation - via MODP Diffie-Hellman calculations [3] Authentication of end-points [4] IPsec SA management (selector negotiation, options negotiation, create, delete, and rekeying) Items 1 through 3 are accomplished in IKE Phase 1, while item 4 is handled in IKE Phase 2. An IKE phase 2 negotiation is performed to establish both an inbound and an outbound IPsec SAs. The traffic to be protected by an IPSec SA is determined by a selector which has been proposed by the IKE initiator and accepted by the IKE responder. In IPsec transport mode, the IPsec SA selector can be a "filter" or traffic classifier, defined as the 5-tuple: . The successful establishment of a IKE Phase-2 SA results in the creation of two uni- directional IPsec SAs fully qualified by the tuple . The session keys for each IPsec SA are derived from a master key, typically a MODP Diffie-Hellman computation. Rekeying of an existing IPsec SA pair is accomplished by creating two new IPsec SAs, making them active, and then optionally deleting the older IPsec SA pair. Typically the new outbound SA is used immediately, and the old inbound SA is left active to receive packets for some locally defined time, perhaps 30 seconds or 1 minute. 1.5. Terminology Fibre Channel Fibre Channel (FC) is a gigabit speed networking technology primarily used to implement Storage Area Networks (SANs). FC is standardized under American National Standard for Information Systems of the National Committee for Information Technology Standards (ANSI-NCITS) in its T11 technical committee. FCIP Fibre Channel over IP (FCIP) is a protocol for interconnecting islands of Fibre Channel SANs over IP Networks so as to form a unified SAN in a single Fibre Channel fabric. iFCP iFCP is a gateway-to-gateway protocol, which provides Fibre Channel fabric services to Fibre Channel devices over a TCP/IP network. Aboba, et al. Informational [Page 5] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 iSCSI iSCSI is a client-server protocol in which clients (Initiators) open connections to servers (Targets). iSNS The Internet Storage Name Server (iSNS) protocol provides for discovery and management of iSCSI and Fibre Channel (FCP) storage devices. iSNS applications store iSCSI and FC device attributes and monitor their availability and reachability, providing a consolidated information repository for an integrated IP storage network. iFCP requires iSNS for discovery and management, while iSCSI may use iSNS for discovery, and FCIP does not use iSNS. Initiator The iSCSI Initiator connects to the Target on well-known TCP port . The iSCSI Initiator then issues SCSI commands for execution by the iSCSI Target. Target The iSCSI Target listens on a well-known TCP port for incoming connections, and returns a status response for each command issued by the iSCSI Initiator, over the same connection. 1.6. Requirements language In this document, the key words "MAY", "MUST, "MUST NOT", "OPTIONAL", "RECOMMENDED", "SHOULD", and "SHOULD NOT", are to be interpreted as described in [2]. Although the security requirements in this document are already incorporated into the iSCSI [1], iFCP [56] and FCIP [57] standards track documents, they are reproduced here for convenience. In the event of a discrepancy, the standards track documents take precedence. 2. iSCSI, iFCP and FCIP security 2.1. Security requirements The iSCSI, iFCP and FCIP protocols are used to transmit SCSI commands over IP networks. Therefore, both the control and data packets of iSCSI, iFCP and FCIP are vulnerable to attack. Examples of attacks include: [1] An adversary may attempt to acquire confidential data and identities by snooping data packets. [2] An adversary may attempt to modify packets containing data and control messages. [3] An adversary may attempt to inject packets into an iSCSI, iFCP or FCIP connection. Aboba, et al. Informational [Page 6] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 [4] An adversary may attempt to hijack TCP connection(s) corresponding to an iSCSI, iFCP or FCIP session. [5] An adversary may launch denial of service attacks against iSCSI, iFCP or FCIP devices or an iSNS server (iFCP only), such as by sending a TCP reset. [6] An adversary may attempt to disrupt security negotiation process, in order to weaken the authentication, or gain access to user passwords. This includes disruption of application-layer authentication negotiations such as iSCSI logon. [7] An adversary may attempt to impersonate a legitimate security gateway or iSNS server (iFCP only). [8] An adversary may attempt to compromise communication that occurs during the discovery process (SLPv2 for FCIP) or discovery and management process (iSNS for iFCP). Since iFCP and FCIP devices are the last line of defense for a whole Fibre Channel island, the above attacks, if successful, could compromise the security of all the Fibre Channel hosts behind the devices. To address the above threats, the iSCSI, iFCP and FCIP security protocols MUST provide confidentiality, data origin authentication, integrity, and replay protection on a per-datagram basis. It also MUST provide a scalable approach to key management. Confidentiality services are important since iSCSI, iFCP and FCIP traffic may traverse insecure public networks. Due to the high data transfer rates and the amount of data involved, iSCSI, iFCP and FCIP security protocols MUST support the capability to rekey each phase 2 SA in time intervals as often as every 25 seconds. The iSCSI, iFCP and FCIP security protocols MUST provide the capability for perfect forward secrecy in the rekeying process. Bi-directional authentication of the communication endpoints MUST be provided. There is no requirement that the identities used in authentication be kept confidential (e.g., from a passive eavesdropper). Given current networking technology, iSCSI, iFCP and FCIP security MUST be implementable at 1 Gbps in terms of CPU overhead and/or availability of suitable hardware e implementations and SHOULD be implementable at 10 Gbps. 10 Gbps implementations are desirable but are not an absolute requirement as implementation feasibility at these speeds is not yet proven. Aboba, et al. Informational [Page 7] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 These performance levels apply to aggregate throughput, and include all TCP connections used between iSCSI, iFCP or FCIP endpoints. iSCSI, iFCP and FCIP communications typically involve multiple TCP connections. Since each IPsec security association only protects a single TCP connection, it does not necessarily need to support the entire aggregate throughput. Through use of multiple processing engines that independently support individual security associations, implementations may be able to scale to 10Gbps throughput in the aggregate. Enterprise data center networks are considered mission-critical facilities that must be isolated and protected from all possible security threats. Such networks are usually protected by security gateways, which at a minimum provide a shield against denial of service attacks. The iSCSI, iFCP and FCIP security architecture should be able to leverage the protective services of the existing security infrastructure, including firewall protection, NAT and NAPT services, and VPN services available on existing security gateways. When iFCP or FCIP devices are deployed within enterprise networks, IP addresses will be typically be statically assigned in the same manner as most routers and switches. Consequently, support for dynamic IP address assignment, as described in [55], will typically not be required, although it cannot be ruled out. Such facilities will also be relevant to iSCSI hosts whose addresses are dynamically assigned. As a result, the iSCSI, iFCP, and FCIP security protocols MUST NOT introduce additional security vulnerabilities where dynamic address assignment is supported. Note that while iSCSI, iFCP and FCIP security is mandatory to implement, it is not mandatory to use. The security services used depend on the configuration and security policies put in place. For example, configuration will influence the authentication algorithm negotiated within iSCSI logon, as well as the security services (encryption, authentication, integrity, replay protection) and transforms negotiated when IPsec is used to protect iSCSI, iFCP or FCIP. It MUST be possible for compliant iSCSI, iFCP and FCIP implementations to administratively disable any and all security mechanisms. FCIP implementations may allow enabling and disabling security mechanisms at the granularity of an FCIP link. For iFCP, the granularity is the session, which corresponds to a TCP connection. iSNS, described in [58], is required in all iFCP deployments. iSCSI may use iSNS for discovery, and FCIP does not use iSNS. iSNS applications store iSCSI and FC device attributes and monitor their availability and reachability, providing a consolidated information repository for an integrated IP storage network. The iSNS specification must define mechanisms to secure communication between an iFCP gateway and iSNS server(s). Aboba, et al. Informational [Page 8] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 2.2. Resource constraints iFCP and FCIP devices will typically be embedded systems deployed on racks in air-conditioned data center facilities. Such embedded systems may include hardware chipsets to provide data encryption, authentication, and integrity processing. Therefore, memory and CPU resources are generally not a constraining factor. iSCSI will be implemented on a variety of systems ranging from large servers running general purpose operating systems to embedded host bus adapters (HBAs). Host Bus Adapter is a generic term for a SCSI interface to other device(s); it's roughly analogous to the term Network Interface Card (NIC) for a TCP/IP network interface, except that HBAs generally have on-board SCSI implementations, whereas most NICs do not implement TCP, UDP, or IP. In general, a host bus adapter is the most constrained iSCSI implementation environment, although an HBA may draw upon the resources of the system to which it is attached in some cases (e.g., authentication computations required for connection setup). More resources should be available to iSCSI implementations for embedded and general purpose operating systems. The following guidelines indicate the approximate level of resources that authentication, keying, and rekeying functionality can reasonably expect to draw upon: - Low power processors with small word size are generally not used, as power is usually not a constraining factor, with the possible exception of HBAs, which can draw upon the computational resources of the system into which they are inserted). Computational horsepower should be available to perform a reasonable amount of exponentiation as part of authentication and key derivation for connection setup. The same is true of rekeying, although the ability to avoid exponentiation for rekeying may be desirable (but is not an absolute requirement). - RAM and/or flash resources tend to be constrained in embedded implementations. 8-10 MB of code and data for authentication, keying, and rekeying is clearly excessive, 800-1000 KB is clearly larger than desirable, but tolerable if there is no other alternative and 80-100 KB should be acceptable. These sizes are intended as rough order of magnitude guidance, and should not be taken as hard targets or limits (e.g., smaller code sizes are always better). Software implementations for general purpose operating systems may have more leeway. The primary resource concern for implementation of authentication and keying mechanisms is code size, as iSCSI assumes that the computational horsepower to do exponentiations will be available. Aboba, et al. Informational [Page 9] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 There is no dominant iSCSI usage scenario - the scenarios range from a single connection constrained only by media bandwidth to hundreds of Initiator connections to a single Target or communication endpoint. SCSI sessions and hence the connections they use tend to be relatively long lived; for disk storage, a host typically opens a SCSI connection on boot and closes it on shutdown. Tape session length tends to be measured in hours or fractions thereof (i.e., rapid fire sharing of the same tape device among different Initiators is unusual), although tape robot control sessions can be short when the robot is shared among tape drives. On the other hand, tape will not see a large number of Initiator connections to a single Target or communication endpoint, as each tape drive is dedicated to a single use at a single time, and a dozen tape drives is a large tape device. 2.3. Security protocol All iSCSI, iFCP, and FCIP security compliant implementations MUST support the ESP protocol [4] to provide security for both control packets and data packets. Conformant iSCSI security implementations MUST support ESP in transport mode. Conformant iFCP and FCIP implementations MUST support ESP in tunnel mode and MAY support ESP in transport mode, such as when there are no intervening IPsec gateways or NA(P)Ts, and use of middleboxes is not contemplated by local administrative policies. All iSCSI, FCIP, and iFCP security compliant implementations MUST support the replay protection mechanisms of IPsec. To provide confidentiality with ESP, ESP with 3DES in CBC mode MUST be supported, and AES in Counter mode, as described in [53], SHOULD be supported. To provide data origin authentication and integrity with ESP, HMAC-SHA1 MUST be supported, and AES in CBC MAC mode with XCBC extensions [38] SHOULD be supported. DES in CBC mode SHOULD NOT be used due to its inherent weakness. If confidentiality is not required but data origin authentication and integrity is enabled, ESP with NULL Encryption MUST be used. Conformant iSCSI, FCIP, and iFCP security implementations MUST support IKE [7] for peer authentication, negotiation of security associations, and key management, using the IPSec DOI [5]. Manual keying MUST NOT be used since it does not provide the necessary rekeying support. Conformant iSCSI, iFCP and FCIP implementations MUST support peer authentication using a pre-shared key, and MAY support certificate-based peer authentication using digital signatures. Peer authentication using the public key encryption methods outlined in IKE's sections 5.2 and 5.3 [7] SHOULD NOT be supported. When pre-shared keys are used for authentication, IKE Aggressive Mode SHOULD be used, and IKE Main Mode SHOULD NOT be used. When digital signatures are used for authentication, either IKE Main Mode or IKE Aboba, et al. Informational [Page 10] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Aggressive Mode MAY be used. In all cases, access to locally stored secret information (pre-shared key, or private key for digital signing) MUST be suitably restricted, since compromise of the secret information nullifies the security properties of the IKE/IPsec protocols. When digital signatures are used to achieve authentication, an IKE negotiator SHOULD use IKE Certificate Request Payload(s) to specify the certificate authority (or authorities) that are trusted in accordance with its local policy. IKE negotiators SHOULD check the pertinent Certificate Revocation List (CRL) before accepting a PKI certificate for use in IKE's authentication procedures. The Phase 2 Quick Mode exchanges used to negotiate protection for the TCP connections used by iSCSI, iFCP and FCP MUST explicitly carry the Identity Payload fields (IDci and IDcr). The DOI [5] provides for several types of identification data. However, when used in conformant iSCSI, iFCP and FCIP security implementations, each ID Payload MUST carry a single IP address and a single non-zero port number, and MUST NOT use the IP Subnet or IP Address Range formats. This allows the Phase 2 security association to correspond to specific TCP and iSCSI, iFCP and FCIP connections. To support authenticaiton between the iSCSI Initiator and Target, the Secure Remote Password (SRP) protocol described in RFC 2945 [48] MUST be implemented within the iSCSI text-based multi-round negotiation mechanism. A number of additional authentication protocols have also been specified in the current iSCSI draft. Negotiation between Initiator and Target is used to determine which authentication algorithm to use (or whether to use one at all); the connection closes if either side requires authentication and no mutually acceptable algorithm can be agreed upon. 3. iSCSI security inter-operability guidelines The following guidelines are established to meet iSCSI security requirements using IPsec in practical situations. 3.1. iSCSI security issues iSCSI provides for iSCSI logon, which includes support for application- layer authentication. This authentication is logically between the iSCSI Initiator and the iSCSI Target (as opposed to between the TCP/IP communication endpoints). The intent of the iSCSI design is that the Initiator and Target represent the systems (e.g., host and disk array or tape system) participating in the communication, as opposed to network communication interfaces or endpoints. Aboba, et al. Informational [Page 11] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 The iSCSI protocol, and iSCSI logon authentication do not meet the security requirements for iSCSI. iSCSI logon authentication provides mutual authentication between the iSCSI Initiator and Target at connection origination, but does not protect control and data traffic on a per packet basis, leaving the iSCSI connection vulnerable to attack. iSCSI logon authentication can mutually authenticates the Initiator to the Target, but does not by itself provide per-packet authentication, integrity, confidentiality or replay protection. In addition, iSCSI logon authentication, outlined in [1], does not provide for a protected ciphersuite negotiation. Therefore, iSCSI logon provides a weak security solution. 3.2. iSCSI and IPsec interaction An iSCSI session [1], comprised of one or more TCP connections, is identified by the 2-tuple of the Initiator-defined identifier and the Target-defined identifier, . Each connection within a given session is assigned a unique Connection Identification, CID. The TCP connection is identified by the 5-tuple . An IPsec Phase 2 SA is identified by the 3-tuple . The iSCSI session and connection information is carried within the iSCSI Login Commands, transported over TCP. Since an iSCSI initiator may have multiple interfaces, iSCSI connections within an iSCSI session may be initiated from different IP addresses. Similarly, multiple iSCSI targets may exist behind a single IP address, so that there may be multiple iSCSI sessions between a given pair. When multiple iSCSI sessions are active between a given pair, the set of TCP connections used by a given iSCSI session must be disjoint from those used by all other iSCSI sessions between the same pair. Therefore a TCP connection can be associated with one and only one iSCSI session. The relationship between iSCSI sessions, TCP connections and IKE Phase 1 and Phase 2 SAs is as follows: [1] An iSCSI initiator or target may have more than one interface, and therefore may have multiple IP addresses. Also, multiple iSCSI initiators and targets may exist behind a single IP address. As a result, an iSCSI Session may correspond to multiple IKE Phase 1 Security Associations, though typically a single IKE Phase 1 security association will exist for an tuple. Aboba, et al. Informational [Page 12] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 [2] Each TCP connection within an iSCSI Session is protected by a separate IKE Phase 2 SA, with selectors specific to that TCP connection. Each IKE Phase 2 SA protects only a single TCP connection, and each TCP connection is transported under only one IKE Phase 2 SA. Given this, all the information needed for the iSCSI/IPsec binding is contained within the iSCSI Login messages from the iSCSI Initiator and Target. This includes the binding between an IKE Phase 1 SA and the corresponding iSCSI sessions, as well as the binding between an IPsec Phase 2 SA and the TCP connection and iSCSI connection ID. 3.3. Initiating a New iSCSI Session In order to create a new iSCSI Session, an Initiator implementing iSCSI security first establishes IKE Phase 1 and Phase 2 SAs, then exchanges iSCSI control messages over an IPsec-secured TCP connection. The iSCSI Initiator contacts the Target on well-known TCP port . The Initiator and Target implementations MUST successfully complete the IKE phase 1 and Phase 2 negotiations before the initial TCP connection setup messages are exchanged so that these messages can be IPsec protected. IPsec implementations configured with the correct policies (e.g. use ESP with non-null transform for all traffic destined to or originating from the iSCSI well-known TCP port) will handle this automatically. Once an IKE Phase 1 SA is established, subsequent iSCSI connections established within the iSCSI session will typically be protected by IKE Phase 2 SAs derived from that IKE Phase 1 SA, although additional IKE Phase 1 SAs can also be brought up. Once the IKE Phase 2 negotiations are complete and the TCP connection is established over IPsec, the iSCSI Initiator MUST send the iSCSI Login command over the TCP connection secured by the recently negotiated Quick Mode SA. The Initiator fills in the ISID field, and leaves the TSID field set to zero, to indicate that it is the first message of a new session establishment exchange. The Initiator also fills in a CID value, that identifies the TCP connection over which the Login command is being exchanged. When the iSCSI Target replies with its Login Command, both iSCSI devices will know the TSID, and therefore the iSCSI session identifier . A single iSCSI session identifier may have multiple associated IKE Phase 1 SAs, and each IKE Phase 1 SA may correspond to multiple iSCSI session identifiers. Each iSCSI connection (identified by the connection identifier) corresponds to a single TCP connection (identified by the 5-tuple) and IPsec Phase 2 SA. Each IKE Phase 2 SA corresponds to a Aboba, et al. Informational [Page 13] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 single IKE Phase 1 SA, and is identified by the combination. Before adding a new TCP connection to an existing iSCSI Session, a new IKE Quick Mode exchange MUST occur, under the protection of an IKE Phase 1 SA. This can be existing IKE Phase 1 SA, or a new IKE Phase 1 SA can be brought up for this purpose. Within IKE, each key refresh requires that a new security association be established. In practice there is a time interval during which an old, about-to-expire SA and newly established SA will both be valid. The IPsec implementation will choose which security association to use based on local policy, and iSCSI concerns play no role in this selection process. 3.4. Graceful iSCSI Teardown Mechanisms within iSCSI provide for both graceful and non-graceful teardown of iSCSI Sessions or individual TCP connections within a given session. The iSCSI Logout command is used to effect graceful teardown. This command allows the iSCSI Initiator to request that: [a] the session be closed [b] a specific connection within the session be closed [c] a specific connection be marked for recovery, or [d] a specific connection be closed at the Target's request. LP Command [d] is distinct from [b] in that it indicates that the connection is being closed in response to a request from the Target for it to be closed. Due to asymmetries in the iSCSI protocol, Targets cannot close a connection on their own initiative. When the iSCSI implementation wishes to close a session, it MUST use the appropriate iSCSI commands to accomplish this. After exchanging the appropriate iSCSI control messages for session closure, the iSCSI security implementation SHOULD initiate a half-close of each TCP connection within the iSCSI session. Since a given IKE Phase 1 SA may correspond to multiple iSCSI sessions, the iSCSI implementation will only delete the IKE Phase 1 SAs corresponding to the iSCSI session if there are no remaining iSCSI sessions corresponding to those SAs. For those Phase 1 SAs that are deleted, the iSCSI security implementation will also delete the IKE Phase 2 SAs bound to them first, before deleting the Phase 1 SA. When the iSCSI security implementation wishes to close an individual TCP connection while leaving the parent iSCSI session active, it SHOULD Aboba, et al. Informational [Page 14] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 half-close the TCP connection. This results in a FIN being sent, putting the TCP connection into the FIN WAIT-1 state, as described in [10]. After the other side responds, the TIME WAIT state is entered. After the expiration of the TIME WAIT timeout, the IKE Phase 2 security association bound to the TCP connection can be closed. Closing the TCP connection prior to deleting the IKE Phase 2 SA ensures that all the TCP packets sent on the connection are IPsec-protected. 3.5. Non-graceful iSCSI Teardown If a given TCP connection unexpectedly fails, the associated iSCSI connection is torn down. Some time after this, the IKE Phase 2 security association will typically be deleted; however, there is no requirement that an IKE Phase 2 delete immediately follow iSCSI connection tear down. Similarly, if the IKE implementation receives a Phase 2 Delete message for a security association corresponding to a TCP connection, this does not necessarily imply that the TCP or iSCSI connection is to be torn down. If a Logout Command/Logout Response sequence marks a connection for removal from the iSCSI session, then after the iSCSI peer has executed an iSCSI teardown process for the connection, the TCP connection will be closed. The iSCSI connection state can then be safely removed. Since the IKE Phase 2 SA corresponding to the TCP connection may not be immediately deleted and can remain up for some time, iSCSI implementations SHOULD NOT depend on receiving the IPsec Phase 2 delete as confirmation that the iSCSI peer has executed an iSCSI teardown process for the connection. Since IPsec acceleration hardware may only be able to handle a limited number of active IKE Phase 2 SAs, Phase 2 delete messages may be sent for idle SAs, as a means of keeping the number of active Phase 2 SAs to a minimum. The receipt of an IKE Phase 2 delete message SHOULD NOT be interpreted as a reason for tearing down the corresponding iSCSI connection if no Logout Command/Logout Receive has been executed on the connection. Rather, it is preferable to leave the iSCSI connection up, and if additional traffic is sent on it, to bring up another IKE Phase 2 SA to protect it. This avoids the potential for continually bringing iSCSI connections up and down. If an IKE implementation receives a Phase 1 Delete message for a Phase 1 Security Association bound to one or more iSCSI sessions, then it SHOULD delete the associated IKE Phase 2 security associations. Aboba, et al. Informational [Page 15] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 3.6. Application-layer CRC iSCSI's error detection and recovery assumes that the TCP and IP checksums provide inadequate integrity protection for high speed communications. As described in [16], when operating at high speeds, the 16-bit TCP checksum [11] will not necessarily detect all errors, resulting in possible data corruption. iSCSI [1] therefore incorporates a 32-bit CRC to protect its headers and data. When a CRC check fails (i.e. CRC computed at receiver does not match the received CRC), the iSCSI PDU covered by that CRC is discarded. Since presumably the error was not detected by the TCP checksum, TCP retransmission will not occur and thus cannot assist in recovering from the error. iSCSI contains both data and command retry mechanisms to deal with the resulting situations, including SNACK, the ability to reissue R2T commands, and the retry (X) bit for commands. IPsec offers protection against an attacker attempting to modify packets in transit, as well as unintentional packet modifications caused by router malfunctions. In general, IPsec authentication transforms afford stronger integrity protection than both the 16-bit TCP checksum and the 32-bit application-layer CRC that has been proposed for use with iSCSI. Since IPsec integrity protection occurs below TCP, if an error is discovered, then the packet will be discarded and TCP retransmission will occur, so that no recovery action need be taken at the iSCSI layer. 3.6.1. Simplification of recovery logic Where IPsec integrity protection is known to be in place, and covers the entire connection between iSCSI endpoints (or the portion that requires additional integrity connection), portions of iSCSI can be simplified. For example, mechanisms to recover from CRC check failures are not necessary. If the iSCSI CRC is negotiated, the recovery logic SHOULD simplified to regard any CRC check failure as fatal (e.g., generate a SCSI CHECK CONDITION on data error, close the corresponding TCP connection on header error) because it will be very rare for errors undetected by IPsec integrity protection to be detected by the iSCSI CRC. 3.6.2. Omission of iSCSI CRC In some situations where IPsec is employed, the iSCSI CRC will not provide additional protection, and can be omitted. For example, where IPsec processing as well as TCP checksum and iSCSI CRC verification are offloaded within the NIC, each of these checks will be verified prior to transferring data across the bus, so that Aboba, et al. Informational [Page 16] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 subsequent errors will not be detected. As a result, where IPsec processing is offloaded to the NIC, the iSCSI CRC is not necessary and the implementations may wish not to negotiate it. However, in other circumstances, the TCP checksum and iSCSI CRC will provide additional protection, and it is desirable to negotiate use of the iSCSI CRC even though IPsec is available. These situations occur where: [1] IPsec, TCP and iSCSI are implemented purely in software. Here, additional failure modes may be detected by the TCP checksum and/or iSCSI CRC. For example, after the IPsec message integrity check is successfully verified, the segment is copied as part of TCP processing, and a memory error during this process might cause the TCP checksum or iSCSI CRC verification to fail. [2] The implementation is an iSCSI-iSCSI proxy or gateway. Here the iSCSI CRC can be propagated from one iSCSI connection to another. In this case, the iSCSI CRC is useful to protect iSCSI data against memory, bus, or software errors within the proxy or gateway, and requesting it is desirable. [3] IPsec is provided by a device external to the actual iSCSI device. Here the iSCSI header and data CRCs can be kept across the part of the connection that is not protected by IPsec. For instance, the iSCSI connection could traverse an extra bus, interface card, network, interface card, and bus between the iSCSI device and the device providing IPsec. In this case, the iSCSI CRC is desirable, and the iSCSI implementation behind the IPsec device may request it. Note that if both ends of the connection are on the same segment, then traffic will be effectively protected by the layer 2 CRC, so that negotiation of the iSCSI CRC is not necessary. 4. iFCP and FCIP security issues 4.1. iFCP and FCIP Authentication Requirements iFCP and FCIP are peer-to-peer protocols. iFCP and FCIP sessions may be initiated by either or both peer gateways. Consequently, bi-directional authentication of peer gateways MUST be provided. iFCP and FCIP are transport protocols that encapsulate SCSI and Fibre Channel (FCP) messages. Therefore, Fibre Channel, operating system, and user identities are transparent to the iFCP and FCIP protocols. IKE and IPsec authentication used to protect iFCP and FCIP traffic shall be based upon the IP addresses of the communicating peer gateways. Aboba, et al. Informational [Page 17] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 iFCP gateways shall use Discovery Domain information obtained from the iSNS server to determine whether the initiating Fibre Channel N_PORT should be allowed access to the target N_PORT. N_PORT identities used in the Port Login (PLOGI) process shall be considered authenticated provided that it is received from the remote gateway over a secure, IPsec-protected connection. There is no requirement that the identities used in authentication be kept confidential. 4.2. iFCP Interaction with IPsec and IKE iFCP and FCIP devices may have more than one interface and IP address. For iFCP, multiple TCP connections to other iFCP devices may exist at each interface and IP address. An active iFCP session is supported by one and only one TCP connection. This iFCP session is identified by the 2-tuple of the two communicating N_PORT ID's (3 byte Fibre Channel Port Identifier). A TCP connection is bound to an iFCP session using the CBIND message. Each IP address supporting iFCP communication can establish one or more Phase-1 IKE Security Associations (SA) to other IP addresses configured at peering iFCP gateways, using the IP address as identity. IKE Phase 1 SAs may be established at gateway initialization, or may be brought up when TCP connections matching the IPsec security policy are established. Unlike Phase-1 SAs, a Phase-2 SA maps to an individual TCP connection. Once the phase 2 security association is established, it protects the TCP setup process and all subsequent TCP traffic. As a result, before a new TCP connection to a remote iFCP or device is established, IKE MUST negotiate a phase 2 security association using Quick Mode to protect that new connection. Where the correct IPsec policy is in place, mandating IPsec protection of packets destined to and from the iFCP well-known port, this will occur automatically. iFCP connections protected by the phase 2 SA are either in the unbound state, or are bound to a specific session. The creation of an IKE Phase-2 SA to protect an iFCP connection may be triggered by a policy rule supplied through a management interface, or by N_PORT properties registered with the iSNS. For iFCP, the use of Key Exchange payload in Quick Mode for perfect forward secrecy may be dictated through a management interface, or by N_PORT properties registered with the iSNS. Multiple implementation strategies, are permitted so as to enable establishment of IKE Phase 2 SAs at different times. Examples of implementation strategies include: Aboba, et al. Informational [Page 18] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 [1] There exists a unique iFCP security policy for all TCP connections regardless of their bound or unbound state. Thus, an unbound TCP connection can be bound to a session without the need to bring up a new IKE Phase-2 SA. [2] There exist multiple choices of iFCP security policy for unbound TCP connections and active sessions. An unbound TCP connection becomes bound to a session after establishing a new IKE Phase-2 SA matching the new security policy for that N_PORT session. [3] The iFCP implementation does not support TCP connections lingering in an unbound state. Both a IKE Phase-2 SA and a TCP connection need to be started anew anytime a new session is identified. If an iFCP implementation strategy uses unbound TCP connections, then an IKE Phase-2 SA MUST protect each of such unbound connections. Upon receiving a Phase 1 delete message, an iFCP implementation MUST tear down all the Phase 2 SAs spawned off of that Phase 1 SA, and then the Phase 1 SA itself. iSNS [52] is an invariant in all iFCP deployments. iFCP gateways use iSNS for discovery services, and MAY use security policies configured in the iSNS as the basis for algorithm negotiation in IKE. iFCP implementations MAY administratively disable any and all security mechanisms, on a per basis. This implies that IKE and IPsec security associations may not be established for one or more sessions. A configuration of this type may be accomplished through a management interface, or through attributes set in the iSNS server. 4.3. FCIP Interaction with IPsec and IKE FCIP entities establish tunnels with other FCIP entities in order to transfer IP encapsulated FC frames. Each tunnel is a separate FCIP Link, and can encapsulate multiple TCP connections. The binding of TCP connections to an FCIP Link is performed using the Fibre Channel World Wide Names (WWNs) of the two FCIP entities. FCIP entities may have more than one interface and IP address, and it is possible for an FCIP Link to contain multiple TCP connections whose FCIP endpoint IP Addresses are different. In this case, an IKE Phase 1 SA is typically established for each FCIP endpoint IP Address pair. For the purposes of establishing an IKE Phase 1 SA, static IP addresses are typically used for identification. Aboba, et al. Informational [Page 19] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Each TCP connection within an FCIP Link uses an independently negotiated IKE Phase 2 (Quick Mode) SA. This is established prior to sending the initial TCP SYN packet and applies to the life of the connection. Phase 2 negotiation is also required for rekeying, in order to protect against replay attacks. FCIP implementations MAY provide administrative management of Confidentiality usage. These management interfaces SHOULD be provided in a secure manner, so as to prevent an attacker from subverting the security process by attacking the management interface. FCIP Entites do not require any user-level authentication, since all FCIP Entities participate in a machine-level tunnel function. FCIP uses SLP for discovery. However, SLP is not used to distribute security policies. 5. Security considerations 5.1. Transport mode versus tunnel mode With respect to storage protocols, the major differences between the IPsec tunnel mode and transport mode are as follows: [1] MTU considerations. Tunnel mode introduces an additional IP header into the datagram that reflects itself in a corresponding decrease in the path MTU seen by packets traversing the tunnel. This may result in a decrease in the maximum segment size of TCP connections running over the tunnel. [2] Dynamic address assignment. Where tunnel mode is used in situations where IP addresses are dynamically assigned (such as with dynamically addressed hosts implementing iSCSI), support for address assignment within IPsec tunnel mode is required. The use of DHCP within IPsec tunnel mode has been proposed for this, as described in [55]. However, this mechanism is not yet widely deployed within IPsec security gateways. [3] NAT traversal. As noted in [20], IPsec tunnel mode ESP can traverse NAT in limited circumstances, whereas transport mode ESP cannot traverse NAT. To enable NAT traversal in the general case, the IPsec NAT traversal functionality described in [21]-[23] can be implemented. More details are provided in the next section. [4] Connection-specific selectors. For both transport and tunnel mode, it is possible to negotiate connection-specific selectors, so that only a single iSCSI, iFCP or FCIP connection will be protected by an IKE Phase 2 SA. While negotiation of connection-specific Aboba, et al. Informational [Page 20] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 selectors is common within IPsec transport mode implementations, IPsec security gateway implementations typically negotiate "ANY to ANY" selectors by default. [5] Firewall traversal. Where a storage protocol is to traverse administrative domains, the firewall administrator may desire to verify the integrity and authenticity of each transiting packet, rather than opening a hole in the firewall for the storage protocol. IPsec tunnel mode lends itself to such verification, since the firewall can terminate the tunnel mode connection while still allowing the endpoints to communicate end-to-end. If desired, the endpoints can in addition utilize IPsec transport mode for end- to-end security, so that they can also verify authenticity and integrity of each packet for themselves. In contrast, carrying out this verification with IPsec transport mode is more complex, since the firewall will need to terminate the IPsec transport mode connection and will need to act as an iSCSI, iFCP or FCIP gateway or TCP proxy, originating a new IPsec transport mode connection from the firewall to the internal endpoint. Such an implementation cannot provide end-to-end authenticity or integrity protection, and an application-layer CRC (iSCSI) or forwarding of the Fibre Channel frame CRC (iFCP and FCIP) is necessary to protect against errors introduced by the firewall. [6] IPsec-application integration. Where IPsec and the application layer protocol are implemented on the same device or host, it is possible to enable tight integration between them. For example, the application layer can request and verify that connections are protected by IPsec, and can obtain attributes of the IPsec security association. While in transport mode implementations the IPsec and application protocol implementations typically reside on the same host, with IPsec tunnel mode, they may reside on different hosts. Where IPsec is implemented on an external gateway, integration between the application and IPsec is typically not possible. This limits the ability of the application to control and verify IPsec behavior. 5.2. NAT traversal As noted in [20], tunnel mode ESP can traverse NAT in a limited set of circumstances. For example, if there is only one protocol endpoint behind a NAT, "ANY to ANY" selectors are negotiated, and the receiver does not perform source address validation, then tunnel mode ESP may successfully traverse NATs. Since ignoring source address validation introduces new security vulnerabilities, and negotiation of specific selectors is desirable so as to limit the traffic that can be sent down Aboba, et al. Informational [Page 21] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 the tunnel, these conditions may not necessarily apply, and tunnel mode NAT traversal will not always be possible. Transport mode ESP cannot traverse NAT, even though ESP itself does not include IP header fields within its message integrity check. This is because the 16-bit TCP checksum is calculated based on a "pseudo-header" that includes IP header fields, and the checksum is protected by the IPsec message integrity check. As a result, the TCP checksum will be invalidated by a NAT located between the two endpoints. Since TCP checksum calculation and verification is mandatory in both IPv4 and IPv6, it is not possible to omit checksum verification while remaining standards compliant. In order to enable traversal of NATs existing while remaining in compliance, iSCSI, iFCP or FCIP security implementations MAY implement IPsec/IKE NAT traversal, as described in [20]-[23]. The IPsec/IKE NAT traversal specification [23] enables UDP encapsulation of IPsec to be negotiated if a NAT is detected in the path. By determining the IP address of the NAT, the TCP checksum can be calculated based on a pseudo-header including the NAT-adjusted address and ports. If this is done prior to calculating the IPsec message integrity check, TCP checksum verification will not fail. 5.3. IKE issues There are situations where it is necessary for IKE to be implemented in firmware. In such situations, it is important to keep the size of the IKE implementation within strict limits. An upper bound on the size of an IKE implementation might be considered to be 800 KB, with 80 KB enabling implementation in a wide range of situations. As noted in Table 1 on the next page, IKE implementations currently exist which meet the requirements. Therefore, while removal of seldomly used IKE functionality (such as the nonce authentication methods) would reduce complexity, implementations typically will not require this in order to fit within the code size budget. Aboba, et al. Informational [Page 22] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Code size | | |Implementation | (octets) | Release | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Linux | | Pluto | 258KB | FreeSWAN | |(FreeSWAN) | | x86 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Racoon | 400KB | NetBSD 1.5 | | (KAME) | | x86 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Isakmpd | 283KB | NetBSD 1.5 | | (Erickson) | | x86 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | WindRiver | 142KB | PowerPC | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Cisco | 222KB | PowerPC | | VPN1700 | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Cisco | 350K | PowerPC | | VPN3000 | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Cisco | 228KB | MIPS | | VPN7200 | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Table 1 - Code Size for IKE implementations Aboba, et al. Informational [Page 23] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 5.4. Rekeying issues It is expected that iSCSI, iFCP and FCIP implementations will need to operate at high speed. For example, implementations operating at 1 Gbps are currently in design, with 10 Gbps implementations to follow shortly thereafter. At these speeds, a single IPsec SA could rapidly cycle through the 32-bit IPsec sequence number space. For example, a single SA operating at 1 Gbps line rate and sending 64 octet packets would exhaust the 32-bit sequence number space in 2200 seconds, or 37 minutes. With 1518 octet packets, exhaustion would occur in 14.5 hours. At 10 Gbs, exhaustion would occur in 220 seconds or 3.67 minutes. With 1518 octet packets, this would occur within 1.45 hours. As a result, iSCSI, iFCP and FCIP implementations operating at speeds of 1 Gbps or less MAY implement the IPsec sequence number extension, described in [49]. 10 Gbps or faster implementations SHOULD implement the extension specification. Note that depending on the transform in use, it is possible that rekeying will be required prior to exhaustion of the sequence number space. Bellare et. al. have formalized this in [51], showing that the insecurity of CBC mode increases as O(s^2/2^n), where n is the block size in bits, and s is the total number of blocks encrypted. These conclusions do not apply to counter mode. This formula sets a limit on the bytes that can be sent on a CBC SA before a rekey is required: B = s * n/8 = (n/8) * 2^(n/2) Where: B = maximum bytes sent on the SA n = block size in bits This means that cipher block size as well as key length need to be considered in the rekey decision. 3DES uses a block size n = 64 bits (2^3 bytes); this implies that the SA must be rekeyed before B = (64/8) * (2^32) = 2^35 bytes are sent. At 1 Gbps, this implies that a rekey will be required every 274.9 seconds (4.6 minutes); at 10 Gbps, a rekey is required every 27.5 seconds. In practice, a safety margin is required so the required rekey times will be even smaller. In terms of the sequence number space, for a 3DES encrypted message of 512 = 2^9 bytes (2^6 blocks) this implies that the key has become insecure after about 2^26 messages. This is s = 2^26 * 2^6 = 2^32 Aboba, et al. Informational [Page 24] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 blocks and (2^32)^2/2^64 = 1. With the 3DES cipher in CBC mode, it would be prudent to rekey more often, such as every 2^20 messages or 2^29 bytes. This would imply a rekey time of 4.29 seconds at 1 Gbps or 0.43 seconds at 10 Gbps. In comparison, AES-CBC uses a block size of 128 bits (2^4 bytes). This enables B = (128/8) * (2^64) = 2^68 bytes to be sent prior to requiring a rekey. This means that the required rekey times are 2^33 times longer than for 3DES. In terms of the sequence number space, for an AES encrypted message of 512 = 2^9 bytes (2^5 blocks) this implies that the key has become insecure after about 2^59 messages (2^59 * 2^5)^2/2^128 = 1. This means that the entire current ESP sequence space of 2^32 messages could be consumed without compromising the key. AES would still permit a safe CBC mode construction if the ESP sequence space were expanded to 48 bits, since (2^48 * 2^5)^2/2^128 = 2^-22. 5.5. Transform issues Since iSCSI, iFCP and FCIP implementations may operate at speeds of 1 Gbps or greater, the ability to offer IPsec security services at high speeds is of intense concern. Since support for multiple algorithms multiplies the complexity and expense of hardware design, one of the goals of the transform selection effort is to find a minimal set of confidentiality and authentication algorithms implementable in hardware at speeds of up to 10 Gbps, as well as being efficient for implementation in software at speeds of 100 Mbps or slower. In this specification, we primarily concern ourselves with IPsec transforms that have already been specified, and for which parts are available that can run at 1 Gbps line rate. Where existing algorithms do not gracefully scale to 10 Gbps, we further consider algorithms for which transform specifications are not yet complete, but for which parts are expected to be available for inclusion in products shipping within the next 12 months. As the state of the art advances, the range of feasible algorithms will broaden and additional mandatory-to-implement algorithms may be considered. Aboba, et al. Informational [Page 25] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Section 5 of RFC 2406 [4] states: "A compliant ESP implementation MUST support the following mandatory-to-implement algorithms: - DES in CBC mode - HMAC with MD5 - HMAC with SHA-1 - NULL Authentication algorithm - NULL Encryption algorithm " The DES algorithm is specified in [29]; implementation guidelines are found in [30], and security issues are discussed in [31],[43], [17]. The DES IPsec transform is defined in [32] and the 3DES in CBC mode IPsec transform is specified in [33]. The MD5 algorithm is specified in [8]; HMAC is defined in [19] and security issues with MD5 are discussed in [19]. The HMAC-MD5 IPsec transform is specified in [24]. The HMAC-SHA1 IPsec transform is specified in [25]. In addition to these existing algorithms, NIST is currently evaluating the following modes [37] of AES, defined in [34],[35]: AES in Electronic Codebook (ECB) confidentiality mode AES in Cipher Block Chaining (CBC) confidentiality mode AES in Cipher Feedback (CFB) confidentiality mode AES in Output Feedback (OFB) confidentiality mode AES in Counter (CTR) confidentiality mode AES CBC-MAC authentication mode The Modes [36] effort is also considering a number of additional algorithms, including the following: PMAC To provide authentication, integrity and replay protection, iSCSI, iFCP and FCIP security implementations MUST support HMAC-SHA1 for authentication, and AES in CBC MAC mode with XCBC extensions SHOULD be supported [38]. HMAC-SHA1 [25] is to be preferred to HMAC-MD5, due to concerns that have been raised about the security of MD5 [9]. HMAC-SHA1 parts are currently available that run at 1 Gbps, the algorithm is implementable in hardware at speeds up to 10 Gbps, and an IPsec transform specification [25] exists. As a result, it is most practical to utilize HMAC-SHA1 as the authentication algorithm for products shipping in the Aboba, et al. Informational [Page 26] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 near future. The HMAC-SHA2 algorithm [28] is also under development, including an IPsec transform [45], so that this may merit consideration in the future. AES in CBC-MAC authentication mode with XCBC extensions was selected since it avoids adding substantial additional code if AES is already being implemented for encryption; an IPsec transform document is available [38]. Authentication transforms also exist that are considerably more efficient to implement than HMAC-SHA1, HMAC-SHA2 or AES in CBC-MAC authentication mode. UMAC [27],[44] is more efficient to implement in software and PMAC [26] is more efficient to implement in hardware. PMAC is currently being evaluated as part of the NIST modes effort [36] but an IPsec transform does not yet exist; neither does a UMAC transform. For confidentiality, the ESP mandatory-to-implement algorithm (DES) is unacceptable. As noted in [17], DES is crackable with modest computation resources, and so is inappropriate for use in situations requiring high levels of security. To provide confidentiality for iSCSI, iFCP, and FCIP, 3DES in CBC mode [33] MUST be supported and AES in Counter Mode [53] SHOULD be supported. Note that for use in high speed implementations, 3DES has significant disadvantages. However, a 3DES IPsec transform has been specified and parts are available that can run at 1 Gbps, so that it is practical to implement 3DES in products for the short term. As described in Appendix A, 3DES software implementations make excessive computational demands at speeds of 100 Mbps or greater, effectively ruling out software-only implementations. In addition, 3DES implementations require rekeying prior to exhaustion of the current 32-bit IPsec sequence number space, and thus would not be able to make use of sequence space extensions, if they were available. This means that 3DES will require very frequent rekeying at speeds of 10 Gbps or faster. Thus, 3DES is inconvenient for use at very high speeds, as well as being impractical for implementation in software at slower speeds (100+ Mbps). 5.6. Fragmentation Issues When certificate authentication is used, and the certificate chains are long enough, then IKE fragmentation can occur. Routers in the path will frequently discard fragments after the initial one, since they typically will not contain full IP headers that can be compared against an Access List. As a result, the endpoints will be unable to establish an IPsec security association. The solution to this problem is to reduce the size of the certificate chain, or to install router code loads that can support fragment filtering. Aboba, et al. Informational [Page 27] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Fragmentation can become a concern when prepending IPsec headers to a frame. One mechanism which can be used to reduce this problem is to utilize path MTU discovery. For example, when TCP is used as the transport for iSCSI, iFCP or FCIP then path MTU discovery [11]-[13], can be used to enable the TCP endpoints to discover the correct MTU, including effects due to IPsec encapsulation. However, Path MTU discovery fails when appropriate ICMP messages are not received by the host. This occurs in IPsec implementations which drop unauthenticated ICMP packets. This can result in blackholing in naive TCP implementations, as described in [14]. Appropriate TCP behavior is described in section 2.1 of [14]: "TCP should notice that the connection is timing out. After several timeouts, TCP should attempt to send smaller packets, perhaps turning off the DF flag for each packet. If this succeeds, it should continue to turn off PMTUD for the connection for some reasonable period of time, after which it should probe again to try to determine if the path has changed." If an ICMP PMTU is received by an IPsec implementation that processes unauthenticated ICMP packets, this value SHOULD be stored in the SA as proposed in [6], and IPsec should also provide notification of this event to TCP so that the new MTU value can be correctly reflected. 5.7. Security Checks When a connection is opened which requires security, iSCSI, iFCP and FCIP SHOULD check to ensure that the connection is protected by IPsec. If IPsec protection is removed on a connection, it MUST be reinstated before iSCSI, iFCP or FCIP packets are sent. Since IPsec verifies that each packet arrives on the correct SA, as long as it can be ensured that IPsec protection is in place, then iSCSI, iFCP and FCIP can be assured that each received packet was sent by a trusted peer. When used with iSCSI, iFCP or FCIP, IPsec MUST negotiate a separate Phase 2 SA for each TCP connection, with selectors specific to the TCP connection. As a result, only traffic for a single TCP connection will flow within each IPsec Phase 2 SA. iSCSI, iFCP and FCIP security implementations need not verify that the IP addresses and TCP port values in the packet match the socket information which was used to setup the connection. This check will be performed by IPsec, preventing malicious peers from sending commands on inappropriate Quick Mode SAs. Aboba, et al. Informational [Page 28] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 5.8. Authentication issues 5.8.1. Machine versus user certificates The certificate credentials provided by the iSCSI Initiator during the IKE negotiation MAY be those of the machine or of the iSCSI user. When machine authentication is used, the machine certificate is typically stored on the iSCSI Initiator and Target during an enrollment process. When user certificates are used, the user certificate can be stored either on the machine or on a smartcard. For iFCP and FCIP, the certificate credentials provided will almost always be those of the device and will be stored on the device. Since the value of a machine certificate is inversely proportional to the ease with which an attacker can obtain one under false pretenses, it is advisable that the machine certificate enrollment process be strictly controlled. For example, only administrators may have the ability to enroll a machine with a machine certificate. While smartcard certificate storage lessens the probability of compromise of the private key, smartcards are not necessarily desirable in all situations. For example, some organizations deploying machine certificates use them so as to restrict use of non-approved hardware. Since user authentication can be provided within iSCSI logon (keeping in mind the weaknesses described earlier), support for machine authentication in IPsec makes it is possible to authenticate both the machine as well as the user. Since iFCP has no equivalent of iSCSI logon, this is not possible with iFCP, and only the machine is authenticated. In circumstances in which this dual assurance is considered valuable, enabling movement of the machine certificate from one machine to another, as would be possible if the machine certificate were stored on a smart card, may be undesirable. Similarly, when user certificate are deployed, it is advisable for the user enrollment process to be strictly controlled. If for example, a user password can be readily used to obtain a certificate (either a temporary or a longer term one), then that certificate has no more security value than the password. To limit the ability of an attacker to obtain a user certificate from a stolen password, the enrollment period can be limited, after which password access will be turned off. Such a policy will prevent an attacker obtaining the password of an unused account from obtaining a user certificate once the enrollment period has expired. Aboba, et al. Informational [Page 29] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 5.8.2. Pre-shared keys Use of pre-shared keys in IKE main mode is vulnerable to man-in-the- middle attacks when used with dynamically addressed hosts (such as with iSCSI Initiators). In main mode it is necessary for SKEYID_e to be used prior to the receipt of the identification payload. Therefore the selection of the pre-shared key may only be based on information contained in the IP header. However, where dynamic IP address assignment is typical, it is often not possible to identify the required pre-shared key based on the IP address. Thus when main mode pre-shared keys are used with iSCSI, iFCP or FCIP entities whose address is dynamically assigned, the same pre-shared key is shared by a group of Initiators and is no longer able to function as an effective shared secret. In this situation, neither the initiator nor responder identifies itself during IKE phase 1; it is only known that both parties are a member of the group with knowledge of the pre- shared key. This permits anyone with access to the group pre-shared key to act as a man-in-the-middle. This vulnerability is typically not of concern with iFCP and FCIP, since iFCP and FCIP devices typically use statically defined addresses, so that individual pre-shared keys are possible within IKE main mode. This vulnerability also does not occur in aggressive mode since the identity payload is sent earlier in the exchange, and therefore the pre- shared key can be selected based on the identity. However, when aggressive mode is used the user identity is exposed and this is often considered undesirable. As a result, where main mode is used with pre-shared keys and dynamically addressed hosts, unless application-layer mutual authentication is performed (e.g. iSCSI logon), the Responder is not authenticated. This enables a rogue Responder in possession of the group pre-shared key to successfully masquerade as the actual Responder and mount a dictionary attack on legacy authentication methods such as CHAP [47]. Such an attack could potentially compromise many passwords at a time. This vulnerability is widely present in existing IPsec implementations. As a result, where iSCSI, iFCP, or FCIP entities utilize dynamic address assignment along with pre-shared key authentication, IKE Agressive Mode MUST be used. 5.8.3. IKE and application-layer authentication In addition to IKE authentication, iSCSI implementations utilize their own authentication methods, such as those described in [48]. Currently, work is underway on Fibre Channel security, so that a similar Aboba, et al. Informational [Page 30] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 authentication process may eventually also apply to iFCP and FCIP as well. While iSCSI provides initial authentication, it does not provide per- packet authentication, integrity or replay protection. This implies that the identity verified in the iSCSI logon is not subsequently verified on reception of each packet. With IPsec, when the identity asserted in IKE is authenticated, the resulting derived keys are used to provide per-packet authentication, integrity and replay protection. As a result, the identity verified in the IKE conversation is subsequently verified on reception of each packet. Let us assume that the identity claimed in iSCSI logon is a user identity, while the identity claimed within IKE is a machine identity. Since only the machine identity is verified on a per-packet basis, there is no way for the recipient to verify that only the user authenticated via iSCSI logon is using the IPsec SA. In fact, IPsec implementations that only support machine authentication typically have no way to distinguish between user traffic within the kernel. As a result, where machine authentication is used, once an IPsec SA is opened, another user on a multi-user machine may be able to send traffic down the IPsec SA. To limit the potential vulnerability, iSCSI, iFCP or FCIP security implementations MUST negotiate a separate IPsec Phase 2 SA for each connection, with descriptors specific to that connection. This will prevent traffic for other connections from traveling within the IPsec SA negotiated for another connection. As a result, if access to the TCP socket used for the connection is exclusive, then access to the corresponding IPsec SA will also be exclusive, even if the IPsec implementation only supports machine authentication. If the IPsec implementation supports user authentication, the user identity asserted within IKE will be verified on a per-packet basis, and stronger assurances can be provided. In this case, the user identity asserted within IKE will be verified on a per-packet basis. In order to provide segregation of traffic between users when user authentication is used, the sender MUST ensure that only traffic from that particular user is sent down the SA. Enforcement of this restriction is the responsibility of the operating system. In kernel mode iSCSI drivers there typically is no user context to perform user authentication. In this case the authentication is closer to machine authentication. In most operating systems device permissions would control the ability to read/write to the device prior to mounting. Aboba, et al. Informational [Page 31] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Once the device is mounted, ACLs set by the filesystem control access to the device. An administrator can access the blocks on the device directly (for instance, by sending pass through requests to the port driver directly such as in Windows NT). In the same way, an administrator can open raw socket and send IPsec protected packets to an iSCSI target. The situation is analogous, and in this respect no new vulnerability is created that didn't previously exist. The Operating system's ACLs need to be effective to protect a device (whether it is a SCSI device or an iSCSI device). 5.9. Use of AES in counter mode When AES in counter mode is used, it is important to avoid reuse of the counter with the same key, even across all time. Counter mode creates ciphertext by XORing generated key stream with plaintext. It is fairly easy to recover the plaintext from two messages counter mode encrypted under the same counter value, simply by XORing together the two packets. The implication of this is that it is almost always an error to use IPsec manual keying with counter mode, except when the implementation takes heroic measures to maintain state across sessions. Another counter mode issue is it makes forgery of correct packets trivial. Counter mode should therefore never be used without also using data authentication. 6. References [1] Satran, J., et al., "iSCSI", Internet draft (work in progress), draft-ietf-ips-iSCSI-06.txt, April 2001. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [3] Kent,S., Atkinson, R., "IP Authentication Header", RFC 2402, November 1998. [4] Kent,S., Atkinson, R., "IP Encapsulating Security Payload (ESP)", RFC 2406, November 1998. [5] Piper, D., "The Internet IP Security Domain of Interpretation of ISAKMP", RFC 2407, November 1998. [6] Atkinson, R., Kent, S., "Security Architecture for the Internet Protocol", RFC 2401, November 1998. [7] Harkins, D., Carrel, D., "The Internet Key Exchange (IKE)", RFC 2409, November 1998. Aboba, et al. Informational [Page 32] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 [8] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, April 1992. [9] Dobbertin, H., "The Status of MD5 After a Recent Attack", CryptoBytes Vol.2 No.2, Summer 1996. [10] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, September 1981. [11] Mogul, J., and S. Deering, "Path MTU Discovery", RFC 1191, November 1990. [12] Knowles, S., "IESG Advice from Experience with Path MTU Discovery", RFC 1435, March 1993. [13] McCann, J., Deering, S. and J. Mogul, "Path MTU Discovery for IP version 6", RFC 1981, August 1996. [14] Lahey, K., TCP Problems with Path MTU Discovery", RFC 2923, September 2000. [15] Paxon, V., "End-to-end internet packet dynamics", IEEE Transactions on Networking 7,3 (June 1999) pg 277-292. [16] Stone J., Partridge, C., "When the CRC and TCP checksum disagree", ACM Sigcomm, Sept. 2000. [17] Cracking DES, O'Reilly & Associates, Sebastapol, CA 2000. [18] Krueger, M., et.al., "iSCSI Requirements and Design Considerations", draft-ietf-ips-iscsi-reqmts-05.txt, Work in Progress, July 2001. [19] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed-Hashing for Message Authentication", RFC 2104, February 1997. [20] Aboba, B., "IPsec-NAT Compatibility Requirements", draft-ietf- ipsec-nat-reqts-00.txt, Work in Progress, June 2001. [21] Huttunen, A. et. al., "UDP Encapsulation of IPsec Packets", draft- ietf-ipsec-udp-encaps-00.txt, June 2001 [22] Dixon, W. et. al., "IPsec over NAT Justification for UDP Encapsulation", draft-ietf-ipsec-udp-encaps-justification-00.txt, June 2001 [23] Kivinen, T., et al., "Negotiation of NAT-Traversal in the IKE", Internet draft (work in progress), draft-ietf-ipsec-nat-t- Aboba, et al. Informational [Page 33] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 ike-00.txt, June 2001. [24] Madson, C., Glenn, R., "The Use of HMAC-MD5-96 within ESP and AH", RFC 2403, November 1998. [25] Madson, C., Glenn, R., "The Use of HMAC-SHA-1-96 within ESP and AH", RFC 2404, November 1998. [26] Rogaway, P., Black, J., "PMAC: Proposal to NIST for a parallelizable message authentication code", http://csrc.nist.gov/encryption/modes/proposedmodes/pmac/pmac- spec.pdf [27] Black, J., Halevi, S., Krawczyk, H., Krovetz, T., Rogaway, P., "UMAC: Fast and provably secure message authentication", Advances in Cryptology - CRYPTO '99, LNCS vol. 1666, pp. 216-233. Full version available from http://www.cs.ucdavis.edu/~rogaway/umac [28] "Descriptions of SHA-256, SHA-384, and SHA-512," http://csrc.nist.gov/cryptval/shs/sha256-384-512.pdf. [29] U.S. DoC/NIST, "Data encryption standard (DES)", FIPS 46-3, October 25, 1999. [30] U.S. DoC/NIST, "Guidelines for implementing and using the nbs data encryption standard", FIPS 74, Apr 1981. [31] Biham, E., Shamir, A., "Differential Cryptanalysis of DES- like cryptosystems", Journal of Cryptology Vol 4, Jan 1991. [32] Madson, C., Doraswamy, N., "The ESP DES-CBC Cipher Algorithm With Explicit IV", RFC 2405, November 1998. [33] Pereira, R., Adams, R., "The ESP CBC-Mode Cipher Algorithms", RFC 2451, November 1998. [34] Daemen, J., Rijman, V., "AES Proposal: Rijndael," NIST AES Proposal, June 1998. http://csrc.nist.gov/encryption/aes/round2/ AESAlgs/Rijndael/Rijndael.pdf [35] Draft FIPS Publication ZZZZ, "Advanced Encryption Standard (AES)", U.S. DoC/NIST, summer 2001. [36] "Symmetric Key Block Cipher Modes of Operation," http://www.nist.gov/modes. [37] "Recommendation for Block Cipher Modes of Operation", National Institute of Standards and Technology (NIST) Special Publication Aboba, et al. Informational [Page 34] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 800-XX, CODEN: NSPUE2, U.S. Government Printing Office, Washington, DC, July 2001. [38] Frankel, S., Kelly, S., Glenn, R., "The AES Cipher Algorithm and Its Use with IPsec", Internet draft (work in progress), draft-ietf- ipsec-ciph-aes-cbc-01.txt, May 2001. [39] Moskowitz, R., Walker, J., "The AES128 OCB Mode of Operation and Its Use with IPsec", Internet draft (work in progress), draft- moskowitz-aes128-ocb-00.txt, September 2001. [40] Lipmaa, H., Rogaway, P., Wagner, D., "CTR-MODE encryption", Comment on mode of operations NIST, Jan 2001. [41] Schneier, B., J. Kelsey, D. Whiting, D. Wagner, C. Hall, and N. Ferguson, "Performance Comparison of the AES Submissions", http://www.counterpane.com/AES-performance.html [42] A. Bosselaers, "Performance of Pentium implementations", http://www.esat.kuleuven.ac.be/~bosselae/ [43] Bellovin, S., "An Issue With DES-CBC When Used Without Strong Integrity", Proceedings of the 32nd IETF, Danvers, MA, April 1995. [44] Krovetz, T., Black, J., Halevi, S., Hevia, A., Krawczyk, H., Rogaway, P., "UMAC: Message Authentication Code using Universal Hashing", Internet draft (work in progress), draft-krovetz- umac-01.txt, October 2000. [45] Frankel, S., Kelly, S., "The Use of SHA-256, SHA-384, and SHA-512 within ESP, AH and IKE," Work in progress. [46] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, November 1998. [47] Simpson, W.,"PPP Challenge Handshake Authentication Protocol (CHAP)," RFC 1994, August 1996. [48] Wu, T., "The SRP Authentication and Key Exchange System", RFC 2945, September 2000. [49] Steve Kent, IPsec sequence number extension proposal, IETF 50. [50] American National Standard for Financial Services X9.52-1998, "Triple Data Encryption Algorithm Modes of Operation", American Bankers Association, Washington, D.C., July 29, 1998. Aboba, et al. Informational [Page 35] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 [51] Bellare, Desai, Jokippi, Rogaway, "A Concrete Treatment of Symmetric Encryption: Analysis of the DES Modes of Operation", 1997, http://www-cse.ucsd.edu/users/mihir/ [52] Bakke, M., et.al., "iSCSI Naming and Discovery", draft-ietf-ips- iscsi-name-disc-02.txt, Work in Progress, August 2001. [53] Walker, J., Moskowitz, R., "The AES128 CTR Mode of Operation and Its Use with IPsec", Internet draft (work in progress), draft- moskowitz-aes128-ctr-00.txt, September 2001. [54] Maughan, D., Schertler, M., Schneider, M., Turner, J., "Internet Security Association and Key Management Protocol (ISAKMP), RFC 2408, November 1998. [55] Patel, B., Aboba, B., Kelly, S., Gupta, V., "DHCPv4 Configuration of IPsec Tunnel Mode", Internet draft (work in progress), draft- ietf-ipsec-dhcp-13.txt, June 2001. [56] Monia, C., et al., "iFCP - A Protocol for Internet Fibre Channel Storage Networking", Internet drafts (work in progress), draft- ietf-ips-ifcp-04.txt, August 2001. [57] Rajagopal, M., et al., "Fibre Channel over TCP/IP (FCIP)", Internet draft (work in progress), draft-ietf-ips-fcovertcpip-05.txt, August 2001. [58] Gibbons, K., et al., "iSNS Internet Storage Name Service", Internet draft (work in progress), draft-ietf-ips-isns-04.txt, June 2001. Aboba, et al. Informational [Page 36] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Appendix A - Software Performance of IPsec Transforms This Appendix provides data on the performance of IPsec encryption and authentication transforms in software. Since the performance of IPsec transforms is heavily implementation dependent, the data presented here may not be representative of performance in a given situation, and are presented solely for purposes of comparison. A.1 Authentication transforms Table A-1 presents the cycles/byte required by the AES-PMAC, AES-CBC- MAC, AES-UMAC, HMAC-MD5, and HMAC-SHA1 algorithms at various packet sizes, implemented in software. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | | Data | AES- | AES-CBC- | AES- | HMAC- | HMAC- | | Size | PMAC | MAC | UMAC | MD5 | SHA1 | | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 64 | 31.22 | 26.02 | 19.51 | 93.66 | 109.27 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 128 | 33.82 | 28.62 | 11.06 | 57.43 | 65.04 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192 | 34.69 | 26.02 | 8.67 | 45.09 | 48.56 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 256 | 33.82 | 27.32 | 7.15 | 41.63 | 41.63 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 320 | 33.3 | 27.06 | 6.24 | 36.42 | 37.46 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 384 | 33.82 | 26.88 | 5.42 | 34.69 | 34.69 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 448 | 33.45 | 26.76 | 5.39 | 32.71 | 31.96 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 512 | 33.82 | 26.67 | 4.88 | 31.22 | 30.57 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 576 | 33.53 | 26.59 | 4.77 | 30.64 | 29.48 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 640 | 33.3 | 26.54 | 4.42 | 29.66 | 28.62 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Aboba, et al. Informational [Page 37] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | | Data | AES- | AES-CBC- | AES- | HMAC- | HMAC- | | Size | PMAC | MAC | UMAC | MD5 | SHA1 | | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 768 | 33.82 | 26.88 | 4.23 | 28.18 | 27.32 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 896 | 33.45 | 27.13 | 3.9 | 27.5 | 25.64 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1024 | 33.5 | 26.67 | 3.82 | 26.99 | 24.71 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1152 | 33.53 | 27.17 | 3.69 | 26.3 | 23.99 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1280 | 33.56 | 26.8 | 3.58 | 26.28 | 23.67 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1408 | 33.58 | 26.96 | 3.55 | 25.54 | 23.41 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1500 | 33.52 | 26.86 | 3.5 | 25.09 | 22.87 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Table A-1: Cycles/byte consumed by the AES-PMAC, AES-CBC-MAC, AES-UMAC, HMAC-MD5, and HMAC-SHA1 authentication algorithms at various packet sizes. Source: Jesse Walker, Intel (See also http://www.cs.ucdavis.edu/~rogaway/umac/perf00.html for additional data) Aboba, et al. Informational [Page 38] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Table A-2 presents the cycles/second required by the AES-PMAC, AES-CBC- MAC, AES-UMAC, HMAC-MD5, and HMAC-SHA1 algorithms, implemented in software, assuming a 1500 byte packet. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Cycles/ | Cycles/sec | Cycles/sec | Cycles/sec | | Transform | octet | @ | @ | @ | | | (software) | 100 Mbps | 1 Gbps | 10 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | AES-UMAC | 3.5 | 43,750,000 | 437,500,000 | 4.375 B | | (8 octets) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | HMAC-SHA1 | 22.87 | 285,875,000 | 2.8588 B | 28.588 B | | (20 octets) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | HMAC-MD5 | 25.09 | 313,625,000 | 3.1363 B | 31.363 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | AES-CBC-MAC | 26.86 | 335,750,000 | 3.358 B | 33.575 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | AES-PMAC | 33.52 | 419,000,000 | 4.19 B | 41.900 B | | (8 octets) | | | | | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Table A-2: Software performance of the HMAC-SHA1, HMAC-MD5, AES-CBC-MAC and AES-PMAC authentication algorithms at 100 Mbps, 1 Gbps, and 10 Gbps line rates (1500 byte packet). Source: Jesse Walker, Intel At speeds of 100 Mbps, AES-UMAC is implementable with only a modest processor, and the other algorithms are implementable, assuming that a single high-speed processor can be dedicated to the task. At 1 Gbps, only AES-UMAC is implementable on a single high-speed processor; multiple high speed processors (1+ Ghz) will be required for the other algorithms. At 10 Gbps, only AES-UMAC is implementable even with multiple high speed processors; the other algorithms will require a prodigious number of cycles/second. Thus at 10 Gbps, hardware acceleration will be required for all algorithms with the possible exception of AES-UMAC. Aboba, et al. Informational [Page 39] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 A.2 Encryption and Authentication transforms Table A-3 presents the cycles/byte required by the AES-CBC, AES-CTR and 3DES-CBC encryption algorithms (no MAC), implemented in software, for various packet sizes. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | Data size | AES-CBC | AES-CTR | 3DES-CBC | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 64 | 31.22 | 26.02 | 156.09 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 128 | 31.22 | 28.62 | 150.89 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192 | 31.22 | 27.75 | 150.89 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 256 | 28.62 | 27.32 | 150.89 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 320 | 29.14 | 28.1 | 150.89 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 384 | 28.62 | 27.75 | 148.29 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 448 | 28.99 | 27.5 | 149.4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 512 | 28.62 | 27.32 | 148.29 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 576 | 28.33 | 27.75 | 147.72 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 640 | 28.62 | 27.06 | 147.77 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Aboba, et al. Informational [Page 40] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | Data size | AES-CBC | AES-CTR | 3DES-CBC | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 768 | 28.18 | 27.32 | 147.42 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 896 | 28.25 | 27.5 | 147.55 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1024 | 27.97 | 27.32 | 148.29 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1152 | 28.33 | 27.46 | 147.13 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1280 | 28.1 | 27.58 | 146.99 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1408 | 27.91 | 27.43 | 147.34 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1500 | 27.97 | 27.53 | 147.85 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Table A-3: Cycles/byte consumed by the AES-CBC, AES-CTR and 3DES-CBC encryption algorithms at various packet sizes, implemented in software. Source: Jesse Walker, Intel Aboba, et al. Informational [Page 41] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Table A-4 presents the cycles/second required by the AES-CBC, AES-CTR and 3DES-CBC encryption algorithms (no MAC), implemented in software, at 100 Mbps, 1 Gbps, and 10 Gbps line rates (assuming a 1500 byte packet). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Cycles/ | Cycles/sec | Cycles/sec | Cycles/sec | | Transform | octet | @ | @ | @ | | | (software) | 100 Mbps | 1 Gbps | 10 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | AES-CBC | 27.97 | 349,625,000 | 3.4963 B | 34.963 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | AES-CTR | 27.53 | 344,125,000 | 3.4413 B | 34.413 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | 3DES -CBC | 147.85 | 1.84813 B | 18.4813 B | 184.813 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Table A-4: Software performance of the AES-CBC, AES-CTR, and 3DES encryption algorithms at 100 Mbps, 1 Gbps, and 10 Gbps line rates (1500 byte packet). Source: Jesse Walker, Intel At speeds of 100 Mbps, AES-CBC and AES-CTR mode are implementable with a high-speed processor, while 3DES would require multiple high speed processors. At speeds of 1 Gbps, multiple high speed processors are required for AES-CBC and AES-CTR mode. At speeds of 1+ Gbps for 3DES, and 10 Gbps for all algorithms, implementation in software is infeasible, and hardware acceleration is required. Aboba, et al. Informational [Page 42] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Table A-5 presents the cycles/byte required for combined encryption/authentication algorithms: AES CBC + CBCMAC, AES CTR + CBCMAC, AES CTR + UMAC, and AES-OCB at various packet sizes, implemented in software. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | AES | AES | AES | | | Data size | CBC + | CTR + | CTR + | AES- | | | CBCMAC | CBCMAC | UMAC | OCB | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 64 | 119.67 | 52.03 | 52.03 | 57.23 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 128 | 70.24 | 57.23 | 39.02 | 44.23 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192 | 58.97 | 55.5 | 36.42 | 41.63 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 256 | 57.23 | 55.93 | 35.12 | 40.32 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 320 | 57.23 | 55.15 | 33.3 | 38.5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 384 | 57.23 | 55.5 | 32.95 | 37.29 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 448 | 58.72 | 55 | 32.71 | 37.17 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 512 | 58.54 | 55.28 | 32.52 | 36.42 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Aboba, et al. Informational [Page 43] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | AES | AES | AES | | | Data size | CBC + | CTR + | CTR + | AES- | | | CBCMAC | CBCMAC | UMAC | OCB | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 576 | 57.81 | 55.5 | 31.8 | 37 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 640 | 57.75 | 55.15 | 31.74 | 36.42 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 768 | 57.67 | 55.5 | 31.65 | 35.99 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 896 | 57.61 | 55.75 | 31.22 | 35.68 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1024 | 57.56 | 55.61 | 31.22 | 35.45 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1152 | 57.52 | 55.21 | 31.22 | 35.55 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1280 | 57.75 | 55.15 | 31.22 | 36.16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1408 | 57.47 | 55.34 | 30.75 | 35.24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1500 | 57.72 | 55.5 | 30.86 | 35.3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Table A-5: Cycles/byte of combined encryption/authentication algorithms: AES CBC + CBCMAC, AES CTR + CBCMAC, AES CTR + UMAC, and AES-OCB at various packet sizes, implemented in software. Aboba, et al. Informational [Page 44] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Table A-6 presents the cycles/second required for the AES CBC + CBCMAC, AES CTR + CBCMAC, AES CTR + UMAC, and AES-OCB encryption and authentication algorithms operating at line rates of 100 Mbps, 1 Gbps and 10 Gbps, assuming 1500 byte packets. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Cycles/ | Cycles/sec | Cycles/sec | Cycles/sec | | Transform | octet | @ | @ | @ | | | (software) | 100 Mbps | 1 Gbps | 10 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | AES | | | | | | CBC + CBCMAC | 57.72 | 721,500,000 | 7.215 B | 72.15 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | AES | | | | | | CTR + CBCMAC | 55.5 | 693,750,000 | 6.938 B | 69.38 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | AES | | | | | | CTR + UMAC | 30.86 | 385,750,000 | 3.858 B | 38.58 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | | | | | | | | | AES-OCB | 35.3 | 441,250,000 | 4.413 B | 44.13 B | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Table A-6: Cycles/second required for the AES CBC + CBCMAC, AES CTR + CBCMAC, AES CTR + UMAC, and AES-OCB encryption and authentication algorithms, operating at line rates of 100 Mbps, 1 Gbps and 10 Gbps, assuming 1500 octet packets. Source: Jesse Walker, Intel At speeds of 100 Mbps, the algorithms are implementable on a high speed processor. At speeds of 1 Gbps, multiple high speed processors are required, and none of the algorithms are implementable in software at 10 Gbps line rate. Acknowledgments Thanks to Steve Bellovin of AT&T Research for useful discussions of this problem space. Aboba, et al. Informational [Page 45] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Authors' Addresses Bernard Aboba Microsoft Corporation One Microsoft Way Redmond, WA 98052 Phone: +1 425 936 6605 EMail: bernarda@microsoft.com William Dixon Microsoft Corporation One Microsoft Way Redmond, WA 98052 Phone: +1 425 703 8729 EMail: wdixon@microsoft.com David L. Black EMC Corporation 42 South Street Hopkinton, MA 01748 Phone: +1 508 435 1000 x75140 EMail: black_david@emc.com Joshua Tseng Nishan Systems 3850 North First Street San Jose, CA 95134-1702 Phone: +1 408 519 3749 EMail: jtseng@nishansystems.com Joseph J. Tardo Broadcom 3151 Zanker Road San Jose, CA 95134 Phone: +1 408 501 8445 Fax: +1 408 501 8460 EMail: jtardo@broadcom.com Mark Bakke Cisco Systems, Inc. 6450 Wedgwood Road, Suite 130 Maple Grove, MN 55311 Aboba, et al. Informational [Page 46] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Phone: +1 763 398 1000 Fax: +1 763 398 1001 EMail: mbakke@cisco.com Steve Senum Cisco Systems, Inc. 6450 Wedgwood Road, Suite 130 Maple Grove, MN 55311 Phone: Fax: +1 763 398 1001 EMail: ssenum@cisco.com Howard Herbert Intel Corporation 5000 West Chandler Blvd. M/S CH7-404 Chandler, Arizona 85226 Phone: +1 480 554 3116 EMail: howard.c.herbert@intel.com Jesse Walker Intel Corporation 2211 NE 25th Avenue Hillboro, Oregon 97124 Phone: +1 503 712 1849 Fax: +1 503 264 4843 Email: jesse.walker@intel.com Julian Satran IBM, Haifa Research Lab MATAM - Advanced Technology Center Haifa 31905, Israel Phone +972 4 829 6264 EMail: Julian_Satran@vnet.ibm.com Ofer Biran IBM, Haifa Research Lab MATAM - Advanced Technology Center Haifa 31905, Israel Phone +972 4 829 6253 Email: biran@il.ibm.com Aboba, et al. Informational [Page 47] INTERNET-DRAFT Securing iSCSI, iFCP & FCIP 5 October 2001 Charles Kunzinger IBM Corporation Research Triangle Park, NC 27709 Phone: +1 919 254 4142 EMail: kunzinge@us.ibm.com Venkat Rangan Rhapsody Networks Inc. 3450 W. Warren Ave. Fremont, CA 94538 Phone: +1 510 743 3018 Fax: +1 510 687 0136 EMail: venkat@rhapsodynetworks.com Franco Travostino Director, Content Internetworking Lab, Nortel Networks 3 Federal Street Billerica, MA 01821 Phone: +1 978 288 7708 EMail: travos@nortelnetworks.com Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. 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