QIRG C. Wang Internet-Draft A. Rahman Intended status: Informational InterDigital Communications, LLC Expires: July 18, 2020 January 15, 2020 Applications and Use Cases for the Quantum Internet draft-wang-qirg-quantum-internet-use-cases-00 Abstract The Quantum Internet has the potential to improve Internet protocol and application functionality by incorporating quantum information technology into the infrastructure of the overall Internet. In this document, we provide an overview of some applications expected to be used on the Quantum Internet, and then categorize them using the standard telecommunications classification of control plane versus data plane functionality. We then provide detailed use cases for selected applications which can help steer the development of the requisite Quantum Internet functionality. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on July 18, 2020. Copyright Notice Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect Wang & Rahman Expires July 18, 2020 [Page 1] Internet-Draft Quantum Internet Use Cases January 2020 to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions used in this document . . . . . . . . . . . . . . 3 3. Terms and Acronyms List . . . . . . . . . . . . . . . . . . . 3 4. Overview of Quantum Internet Applications . . . . . . . . . . 4 5. Selected Quantum Internet Use Cases . . . . . . . . . . . . . 5 5.1. Secure Communication Setup . . . . . . . . . . . . . . . 6 5.2. Distributed Quantum Computing . . . . . . . . . . . . . . 7 5.3. Secure Quantum Computing with Privacy Preservation . . . 9 6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 11 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 8. Security Considerations . . . . . . . . . . . . . . . . . . . 12 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 10. Informative References . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 1. Introduction The classical Internet has been constantly growing since it first became commercially popular in the early 1990's. It essentially consists of a large number of end-nodes (e.g., laptops, smart phones, network servers) connected by routers. The end-nodes run applications that provide some value added service for the end-users such as processing and transmission of voice, video or data. The physical connections between the various nodes in the Internet include Digital Subscriber Lines (DSLs), fiber optics, etc. Bits are transmitted across the classical Internet in packets. Research and experimentation have picked up over the last few years for developing a Quantum Internet [Wehner]. It is anticipated that the Quantum Internet will provide intrinsic benefits such as better end-user and network security. The Quantum Internet will have end- nodes, which must be quantum computers, connected by quantum repeaters/routers. These quantum computer end-nodes will also run value-added applications which will be discussed later. The physical connections between the various nodes in the Quantum Internet are expected to be primarily fiber optics and free-space optics. Unlike the classical Internet, qubits (and not classical bits or packets) are expected to be transmitted across the Quantum Internet due to the underlying physics [I-D.irtf-qirg-principles]. Wang & Rahman Expires July 18, 2020 [Page 2] Internet-Draft Quantum Internet Use Cases January 2020 The Quantum Internet is not anticipated to replace the classical Internet. Instead the Quantum Internet will be integrated into the classical Internet to form a new hybrid Internet. The process of integrating the Quantum Internet with the classical Internet is similar to, but with more profound implications, as the process of introducing any new communication and networking paradigm into the existing Internet. 2. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. Terms and Acronyms List This document assumes that the reader is familiar with the quantum information technology related terms and concepts that are described in [I-D.irtf-qirg-principles]. In addition, the following terms and acronyms are defined here for clarity: o Bit - Binary Digit (i.e., fundamental unit of information in a classical computer). o Classical Internet - The existing, deployed Internet (circa 2020) where bits are transmitted in packets between nodes to convey information. o Control Plane - Network functions and processes that operate on (1) control bits/packets or qubits (e.g., to setup up end-user encryption); or (2) management bits/packets or qubits (e.g., to configure nodes). o Data Plane - Network functions and processes that operate on end- user application bits/packets or qubits (e.g., voice, video, data). Sometimes also referred to as the user plane. o End-node - An end-node hosts user applications and interfaces with the rest of the Internet. Typically, an end-node may serve in a client, server, or peer-to-peer role as part of the application. If the end-node is part of the Quantum Internet it must be a quantum computer and be able to transmit and receive qubits. It may optionally also interface to the classical Internet and thus be able to transmit and receive classical bits/packets. o Hybrid Internet - The "new" or evolved Internet to be formed due to a merger of the classical Internet and the Quantum Internet. Wang & Rahman Expires July 18, 2020 [Page 3] Internet-Draft Quantum Internet Use Cases January 2020 o NISQ - Noisy Intermediate-Scale Quantum o Packet - Formatted unit of multiple related bits. o Quantum Internet - A new type of network enabled by quantum information technology where qubits are transmitted between nodes to convey information (Note: qubits must be sent individually and not in packets). The Quantum Internet will be merged into the classical Internet to form a new hybrid Internet. o QC - Quantum Computer o QKD - Quantum Key Distribution o Qubit - Quantum Bit (i.e., fundamental unit of information in a quantum computer). It is similar to a classic bit in that the state of a qubit is either "0" or "1" after it is measured and is denoted as its basis state |0> or |1>. However, the qubit is different than a classic bit in that the qubit is in a linear combination of both states before it is measured and termed to be in superposition. A photon or an electron can be used to represent a qubit. 4. Overview of Quantum Internet Applications The Quantum Internet is expected to be extremely beneficial for a subset of existing and new applications. We use "applications" in the widest sense of the word and include functionality typically contained in Layers 4 (Transport) to Layers 7 (Application) of the Open System Interconnect (OSI) model. The expected applications are still being developed as we are in the formative stages of the Quantum Internet [Castelvecchi] [Wehner]. However, a tentative (and non-exhaustive) list of the applications to be supported on the Quantum Internet can be identified and classified as below. From the list it is clear that a variety of control plane and data plane applications will run on the Quantum Internet. Control Plane Applications using Quantum Internet: 1. Secure communication setup - Refers to secure cryptographic key distribution between two or more end-nodes. The most well-known method is referred to as QKD [Renner]. 2. Fast Byzantine negotiation - Refers to a quantum network based method for fast agreement in Byzantine negotiations [Fitzi]. This can be used for the popular financial blockchain feature as Wang & Rahman Expires July 18, 2020 [Page 4] Internet-Draft Quantum Internet Use Cases January 2020 well as other distributed computing features which use Byzantine negotiations. 3. Network clock synchronization - Refers to a world wide set of atomic clocks connected by the Quantum Internet to achieve an ultra precise clock signal [Komar]. 4. Position verification - Refers to a method for an end-node to prove that it is at a particular location to, for example, access a specific service [Unruh]. Data Plane Applications using Quantum Internet: 1. Distributed quantum computing - Refers to a collection of remote small capacity quantum computers (i.e., each supporting a few qubits) that are connected and working together in a coordinated fashion so as to simulate a virtual large capacity quantum computer [VanMeter]. 2. Secure quantum computing with privacy preservation - Refers to private, or blind, quantum computation, which provides a way for a client to delegate a computation task to one or more remote quantum computers without disclosing the source data to be computed over [Fitzsimons]. It is also important to understand which applications will not be supported on the Quantum Internet. Many existing applications have no clear advantage if transmitted over the Quantum Internet and so are not expected to be migrated there. Key examples are Voice over IP (VoIP) calls, streaming video sessions, and web browsing sessions. These applications usually have a real-time human end-user and/or involve high bandwidth content transmission. These applications are better suited to remain on the classical Internet. A given end-node may need to support both a classical Internet interface and a Quantum Internet interface as will be illustrated in some of the use cases below. 5. Selected Quantum Internet Use Cases The Quantum Internet will support a variety of applications and deployment configurations. This section details a few key use cases. In system engineering, a use case is typically made up of a set of possible sequences of interactions between nodes and users in a particular environment and related to a particular goal. This will be the definition that we use in this section. Wang & Rahman Expires July 18, 2020 [Page 5] Internet-Draft Quantum Internet Use Cases January 2020 5.1. Secure Communication Setup In this scenario, two banks (i.e., Bank #1 and Bank #2) need to have secure communications for transmitting important financial transaction records (see Figure 1). For this purpose, they first need to securely exchange a classic secret cryptographic key (i.e., a sequence of classical bits), which is triggered by an end-user banker at Bank #1. This results in a source quantum node A at Bank #1 to securely send a classic secret key to a destination quantum node B at Bank #2. This is referred to as a secure communication setup. One requirement for this secure communication setup process is that it should not be vulnerable to any classic or quantum computing attack. This can be realized using QKD [ETSI-QKD]. QKD can securely distribute a secret key between two quantum nodes, without physically transmitting it through the network and thus achieving the required security. QKD is the most mature feature of the quantum information technology, and has been commercially deployed in small-scale and short-distance deployments. In general, QKD (e.g., [BB84]) without using entanglement works as follows: 1. The source quantum node A transforms the secret key to qubits. Basically, for each classical bit in the secret key, the source quantum node A randomly selects one quantum computational basis and uses it to prepare/generate a qubit for the classical bit. 2. The source quantum node A sends qubits to the destination quantum node B via quantum channel. 3. The destination quantum node receives qubits and measures them based on its random quantum basis. 4. The destination quantum node sends the measurement results (i.e., classic bits) to the source quantum node via any public classic channel. 5. Both the source node and the destination node inform each other's random quantum basis. 6. Both nodes discard any measurement bit under different quantum basis and store all remaining bits as the secret key. Note that there are some entanglement-based QKD protocols such as [Treiber], which work differently than above steps. In addition, For large-scale QKD, one or multiple trusted QKD relays [Zhang] may exist between the source quantum node A and the destination quantum node B. Wang & Rahman Expires July 18, 2020 [Page 6] Internet-Draft Quantum Internet Use Cases January 2020 As a result, the Quantum Internet in Figure 1 may contain quantum channels, quantum repeaters/routers [I-D.irtf-qirg-principles], and/ or trusted QKD relays. +---------------+ | End User | |(e.g., Banking | | Application) | +---------------+ ^ | User Interface | (e.g., GUI) V +-----------------+ /--------\ +-----------------+ | |--->( Quantum )--->| | | Source | ( Internet ) | Destination | | Quantum | \--------/ | Quantum | | Node A | | Node B | | (e.g., Bank #1) | /--------\ | (e.g., Bank #2) | | | ( Classical) | | | |<-->( Internet )<-->| | +-----------------+ \--------/ +-----------------+ Figure 1: Secure Communication Setup 5.2. Distributed Quantum Computing In this scenario, Noisy Intermediate-Scale Quantum (NISQ) computers distributed in different locations are available for sharing. According to the definition in [Preskill], a NISQ computer can only realize a small number of qubits and has limited quantum error correction. In order to gain higher computation power before fully- fledged quantum computers become available, NISQ computers can be connected via classic and quantum channels. As an example, scientists can leverage these connected NISQ computer to solve highly complex scientific computation problems such as analysis of chemical interactions for medical drug development (see Figure 2). In this case, qubits will be transmitted among connected quantum computers via quantum channels, while classic control messages will be transmitted among them via classic channels for coordination and control purpose . Qubits from one NISQ computer to another NISQ computer are very sensitive and cannot be lost. For this purpose, quantum teleportation can be leveraged to teleport Wang & Rahman Expires July 18, 2020 [Page 7] Internet-Draft Quantum Internet Use Cases January 2020 sensitive data qubits from one quantum computer A to another quantum computer B. Specifically, the following steps happen between A and B: 1. The quantum computer A locally generates some sensitive data qubits to be teleported to the quantum computer B. 2. The quantum computer A first establishes a shared entanglement with the quantum computer B (i.e., there are two entangled bits: |q1> at A and |q2> at B). 3. Then, the quantum computer A performs a Bell measurement of the entangled qubit |q1> and the sensitive data qubit. 4. The result from this Bell measurement will be encoded in two classic bits, which will be physically transmitted via a classic channel to the quantum computer B. 5. Based on the received two classic bits, the quantum computer B modifies the state of the entangled qubit |q2> in the way to generate a new qubit identical to the sensitive data qubit at the quantum computer A. In Figure 2, the Quantum Internet contains quantum channels and quantum repeaters/routers [I-D.irtf-qirg-principles]. Wang & Rahman Expires July 18, 2020 [Page 8] Internet-Draft Quantum Internet Use Cases January 2020 +-----------------+ | End-User | |(e.g., Scientist)| +-----------------+ ^ |User Interface (e.g. GUI) | +------------------+-------------------+ | | | | V V +----------------+ /--------\ +----------------+ | |--->( Quantum )--->| | | | ( Internet ) | | | Quantum | \--------/ | Quantum | | Computer A | | Computer B | | (e.g., Site #1)| /--------\ | (e.g., Site #2)| | | ( Classical) | | | |<-->( Internet )<-->| | +----------------+ \--------/ +----------------+ Figure 2: Distributed Quantum Computing 5.3. Secure Quantum Computing with Privacy Preservation Secure computation with privacy preservation refers to the scenario: 1. A client node with source data delegates the computation of the source data to a remote computation node. 2. Furthermore, the client node does not want to disclose any source data to the remote computation node and thus preserve the source data privacy. 3. Note that there is no assumption or guarantee that the remote computation node is a trusted entity from the source data privacy perspective. As an example illustrated in Figure 3, the client node could be a virtual voice-controlled home assistant device like Amazon's Alexa product. The remote computation node could be a quantum computer in the cloud. A resident as an end-user uses voice to control the home device. The home device captures voice-based commands from the end- user. Then, the home device interfaces to a home quantum terminal node (e.g., a home gateway), which interacts with the remote computation node to perform computation over the captured voice-based commands. Wang & Rahman Expires July 18, 2020 [Page 9] Internet-Draft Quantum Internet Use Cases January 2020 In this particular case, there is no privacy concern since the source data (i.e., captured voice-based commands) will not be sent to the remote computation node which could be compromised. Protocols [Fitzsimons] for delegated quantum computing or blind quantum computation can be leveraged to realize secure delegated computation and guarantee privacy preservation simultaneously. Using delegated quantum computing protocols, the client node does not need send the source data but qubits with some measurement instructions to the remote computation node (e.g., a quantum computer). After receiving qubits and measurement instructions, the remote computation node performs the following actions: 1. It first performs certain quantum operations on received qubits and measure them according to received measurement instructions to generate computation results (in classic bits). 2. Then it sends the computation results back to the client node via classic channel. 3. In this process, the source data is not disclosed to the remote computation node and the privacy is preserved. In Figure 3, the Quantum Internet contains quantum channels and quantum repeaters/routers [I-D.irtf-qirg-principles]. Wang & Rahman Expires July 18, 2020 [Page 10] Internet-Draft Quantum Internet Use Cases January 2020 +----------------+ | End-User | |(e.g., Resident)| +----------------+ ^ | User Interface | (e.g., voice commands) V +----------------+ | Home Device | +----------------+ ^ | Classic | Channel V +----------------+ /--------\ +----------------+ | |--->( Quantum )--->| | | Quantum | ( Internet ) | Remote | | Terminal | \--------/ | Computation | | Node | | Node | | (e.g., Home | /--------\ | (e.g., QC | | Gateway) | ( Classical) | in Cloud) | | |<-->( Internet )<-->| | +----------------+ \--------/ +----------------+ Figure 3: Secure Computation with Privacy Preservation 6. Conclusion This document provides an overview of some expected applications for the Quantum Internet and details selected use cases. One key take away is that a variety of control plane applications will run on the Quantum Internet. In contrast, the data plane applications running on the Quantum Internet will be focused on supporting different forms of remote quantum computing. This set of applications may, of course, naturally expand over time as the Quantum Internet matures. This document can also serve as an introductory text to persons interested in learning about the practical uses of the Quantum Internet. Finally, it is hoped that this document will help guide further research and development of the specific Quantum Internet functionality required to implement the applications and uses cases described herein. Wang & Rahman Expires July 18, 2020 [Page 11] Internet-Draft Quantum Internet Use Cases January 2020 7. IANA Considerations This document requests no IANA actions. 8. Security Considerations This document does not define an architecture nor a specific protocol for the Quantum Internet. It focuses on detailing use cases and describing typical Quantum Internet applications. However, some useful observations can be made regarding security as follows. It has been clearly identified that once large-scale quantum computing becomes reality it will be able to theoretically break many of the public-key (i.e., asymmetric) cryptosystems currently in use because of the exponential increase of computing power with quantum computing. This would negatively affect many of the security mechanisms currently in use on the classic Internet. This has given strong impetus for starting development of new cryptographic systems that are secure against quantum computing attacks [NISTIR8240]. Paradoxically, development of a Quantum Internet will also mitigate the threats posed by quantum computing attacks against public-key cryptosystems. Specifically, the secure communication setup feature of the Quantum Internet as described in Section 5.1 will be strongly resistant to both classical and quantum computing attacks. Finally, Section 5.3 provides a method to perform remote quantum computing while preserving the privacy of the source data. 9. Acknowledgments The authors want to thank Xavier de Foy for his very useful review and comments to the document. 10. Informative References [BB84] Bennett, C. and G. Brassard, "Quantum Cryptography: Public Key Distribution and Coin Tossing", 1984, . [Castelvecchi] Castelvecchi, D., "The Quantum Internet has arrived (and it hasn't)", Nature 554, 289-292, 2018, . Wang & Rahman Expires July 18, 2020 [Page 12] Internet-Draft Quantum Internet Use Cases January 2020 [ETSI-QKD] ETSI GR QKD 003 V2.1.1, "Quantum Key Distribution (QKD): Components and Internal Interfaces", 2018, . [Fitzi] Fitzi, M. and et. al., "A Quantum Solution to the Byzantine Agreement Problem", 2001, . [Fitzsimons] Fitzsimons, J., "Private Quantum Computation: An Introduction to Blind Quantum Computing and Related Protocols", 2017, . [I-D.dahlberg-ll-quantum] Dahlberg, A., Skrzypczyk, M., and S. Wehner, "The Link Layer service in a Quantum Internet", draft-dahlberg-ll- quantum-03 (work in progress), October 2019. [I-D.irtf-qirg-principles] Kozlowski, W., Wehner, S., Meter, R., and B. Rijsman, "Architectural Principles for a Quantum Internet", draft- irtf-qirg-principles-02 (work in progress), November 2019. [I-D.van-meter-qirg-quantum-connection-setup] Meter, R. and T. Matsuo, "Connection Setup in a Quantum Network", draft-van-meter-qirg-quantum-connection-setup-01 (work in progress), September 2019. [Komar] Komar, P. and et. al., "A Quantum Network of Clocks", 2013, . [NISTIR8240] Alagic, G. and et. al., "Status Report on the First Round of the NIST Post-Quantum Cryptography Standardization Process", NISTIR 8240, 2019, . [Preskill] Preskill, J., "Quantum Computing in the NISQ Era and Beyond", 2018, . [Renner] Renner, R., "Security of Quantum Key Distribution", 2006, . Wang & Rahman Expires July 18, 2020 [Page 13] Internet-Draft Quantum Internet Use Cases January 2020 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [Treiber] Treiber, A. and et. al., "A Fully Automated Entanglement- based Quantum Cyptography System for Telecom Fiber Networks", New Journal of Physics, 11, 045013, 2009, . [Unruh] Unruh, D., "Quantum Position Verification in the Random Oracle Model", 2014, . [VanMeter] Van Meter, R. and S. Devitt, "Quantum internet: A vision for the road ahead", IEEE 49, 2016, . [Wehner] Wehner, S., Elkouss, D., and R. Hanson, "Quantum internet: A vision for the road ahead", Science 362, 2018, . [Zhang] Zhang, Q., Hu, F., Chen, Y., Peng, C., and J. Pan, "Large Scale Quantum Key Distribution: Challenges and Solutions", Optical Express, OSA, 2018, . Authors' Addresses Chonggang Wang InterDigital Communications, LLC 1001 E Hector St Conshohocken 19428 USA Email: Chonggang.Wang@InterDigital.com Akbar Rahman InterDigital Communications, LLC 1000 Sherbrooke Street West Montreal H3A 3G4 Canada Email: rahmansakbar@yahoo.com Wang & Rahman Expires July 18, 2020 [Page 14]