Network Working Group T. Jahnke Internet-Draft Aviontex GmbH Intended status: Standards Track May 30, 2025 Expires: November 30, 2025 Universal Trust Anchor Self-Revocation Extension for Critical Internet Infrastructure draft-jahnke-ca-self-revocation-01 Abstract This document defines a cryptographically secure mechanism for Certificate Authorities (CAs) and other self-signed trust anchors to perform controlled self-revocation upon compromise detection. This addresses a fundamental architectural paradox in current internet infrastructure: self-signed trust anchors (PKI Root CAs, DNSSEC KSKs, Code Signing Roots, Government PKIs, Industrial Control System CAs, Mobile Platform Roots, and Critical Infrastructure Trust Anchors) cannot be cryptographically revoked because any revocation mechanism requires the anchor's private key, but if attackers possess that key (the primary threat), they control the revocation process. This specification solves this 25-year-old "unsolvable" problem by making attackers inadvertently help terminate their own attacks. The mechanism provides automated detection with mandatory manual authorization, enabling trust anchor operators to terminate anchor validity within hours instead of months while maintaining strict dual-person control. This addresses fundamental architectural limitations exposed by historical incidents such as the DigiNotar compromise in 2011 and Symantec certificate missuance incidents, where extended cleanup periods affected millions of users globally, as well as theoretical compromise scenarios affecting DNSSEC, government PKI, industrial control systems, and other critical infrastructure trust anchors. 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 November 30, 2025. Jahnke Expires November 30, 2025 [Page 1] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 Copyright Notice Copyright (c) 2025 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 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 ....................................................4 1.1. Genesis of This Solution ...................................5 1.2. Key Innovation: Solving the "Unsolvable" Paradox ..........5 1.3. Universal Applicability ...................................6 1.4. Backward Compatibility ....................................6 1.5. Design Philosophy .........................................7 2. Conventions Used in This Document ...............................7 3. Terminology .....................................................7 4. Problem Statement ...............................................9 4.1. Current Trust Infrastructure Vulnerabilities ..............9 4.2. The Mathematical Impossibility Consensus ..................9 4.3. 25-Year Evolution of an "Unsolvable" Problem .............10 4.4. Universal Trust Anchor Problem Analysis ..................11 4.5. Gap Analysis ..............................................12 5. Solution Overview ..............................................13 5.1. Architecture ..............................................13 5.2. Solving the "Unsolvable" Mathematical Paradox ............14 5.3. Emergency Response Timeline ...............................15 5.4. Operational Flow ..........................................15 5.5. Security Properties .......................................16 6. RTO-Extension Definition .......................................16 6.1. Extension Syntax ..........................................16 6.2. Extension Structure .......................................17 6.3. Extension Semantics .......................................17 6.4. Cryptographic Protection Requirements .....................18 6.5. Emergency Signing Key Management ..........................21 6.6. Signal Format Specification ...............................22 6.7. HSM Compromise and Alternative Signing Scenarios ..........23 7. Implementation Requirements ....................................24 7.1. Trust Anchor Security Requirements ........................24 7.2. Emergency Key Infrastructure ..............................25 7.3. Trust Anchor Implementation Requirements ..................26 7.4. High-Availability Monitoring Requirements .................27 Jahnke Expires November 30, 2025 [Page 2] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 7.5. Legacy System Compatibility ...............................27 7.6. Automation Prohibition ....................................28 8. Operational Procedures .........................................29 8.1. Normal Operations ..........................................29 8.2. Signal Detection and Verification .........................29 8.3. Emergency Authorization Process ...........................30 8.4. Manual Signal Generation ..................................30 8.5. Distribution and Verification .............................30 8.6. Post-Revocation Procedures ................................31 9. Security Considerations ........................................31 9.1. Fundamental Security Principle ............................31 9.2. Threat Model Analysis .....................................32 9.3. Operational Security ......................................34 9.4. Privacy and Confidentiality ...............................34 9.5. Cryptographic Security ....................................35 9.6. Cross-Domain Security Considerations ......................35 9.7. Frequently Misunderstood Design Decisions .................36 10. IANA Considerations ...........................................38 10.1. Object Identifier Allocation .............................38 10.2. RTO-Extension Registry ....................................38 10.3. Signal Format Registry ...................................39 10.4. Trust Anchor Type Registry ...............................39 11. Deployment Considerations .....................................40 11.1. Migration Timeline .......................................40 11.2. Backward Compatibility Strategy ..........................41 11.3. Cost-Benefit Analysis ....................................41 12. References ....................................................42 12.1. Normative References .....................................42 12.2. Informative References ...................................43 Appendix A. Implementation Examples ...............................44 A.1. OpenSSL Configuration Example .............................44 A.2. Emergency Response Procedure ..............................45 A.3. Cross-Domain Implementation Examples ......................46 Appendix B. Frequently Asked Questions ............................47 B.1. Security Questions ........................................47 B.2. Implementation Questions ..................................48 Appendix C. Test Vectors ..........................................49 C.1. URL Encryption Test Vector ................................49 C.2. Emergency Signal Validation Test Vector ...................50 Appendix D. Document History ......................................51 D.1. Changes from version -00 to version -01 ...................51 D.2. Implementation Notes ......................................56 Appendix E. Historical Incident Analysis ..........................57 E.1. Historical Incident Analysis ..............................57 E.2. Cross-Domain Trust Anchor Vulnerabilities .................58 E.3. DNSSEC Root Key Compromise Analysis .......................59 Jahnke Expires November 30, 2025 [Page 3] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 1. Introduction Current Public Key Infrastructure (PKI) and other critical internet trust systems lack efficient mechanisms for self-signed trust anchors to rapidly terminate their own validity upon key compromise detection. This fundamental gap affects not only Certificate Authorities (CAs) but also DNSSEC Key Signing Keys, Code Signing Roots, Government PKI systems, Industrial Control System trust anchors, Mobile Platform authorities, and other critical infrastructure trust systems. Historical incidents have demonstrated that trust anchor compromise cleanup can require months or years, during which time attackers can continue to issue fraudulent certificates, manipulate DNS responses, distribute malicious software, or compromise critical infrastructure systems. This work was developed as part of security enhancements for the keweonDNS project by Aviontex GmbH, a public DNS-Security infrastructure requiring high-security trust anchor implementation across multiple critical systems. The critical nature of internet infrastructure demands trust anchor solutions that can respond to compromise incidents within hours rather than months, while maintaining strict operational controls across all trust anchor types. The mechanism described in this specification is commonly referred to as the "RTO-Extension" (Root-TurnOff Extension) in technical discussions and implementations in all critical infrastructure domains. 1.1. Genesis of This Solution This specification originated from a practical trust anchor implementation project that exposed fundamental gaps in existing standards in multiple critical infrastructure domains. While developing an enterprise PKI system for public DNS-Security infrastructure, the authors encountered the realization that compromised trust anchors in all critical systems have no standardized method for rapid self-termination. The key insight emerged during a discussion of threat scenarios: "What if someone gets our Root CA private key?" The traditional answer involved manual trust store updates taking months or years. This led to the broader question of why trust anchors cannot perform cryptographic self-termination. The security community in all critical infrastructure domains has long acknowledged this as an architecturally impossible problem. As documented in Stack Overflow security discussions, "You can't revoke a trusted Root CA certificate, because it is self-signed by the CA and therefore there is no trusted mechanism by which to verify a CRL." This limitation extends identically to DNSSEC KSKs, Code Signing Roots, and other self-signed trust anchors. Jahnke Expires November 30, 2025 [Page 4] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 1.2. Key Innovation: Solving the "Unsolvable" Paradox The RTO-Extension mechanism is mathematically secure for all trust anchor types: it can only be activated by an entity possessing the trust anchor's private key. However, if an attacker gains access to the private key (the primary concern in any trust anchor compromise), they would inadvertently help limit their own attack by triggering the self-revocation mechanism. This specification resolves the mathematical paradox through an elegant insight: if an attacker possesses the trust anchor private key (enabling the compromise), they also possess the capability to generate valid Root-TurnOff CRLs or equivalent revocation signals. By designing the system so that aggressive use of the compromised key triggers detection and subsequent self-termination, attackers inadvertently limit their own attack duration in all affected systems. This transforms the fundamental weakness (private key compromise) into a self-limiting mechanism, solving what security communities in all critical infrastructure domains have considered an architecturally impossible problem for 25+ years. Mathematical Elegance of the Solution: The approach demonstrates optimal game-theoretic properties: - Conservative Attack: Attacker avoids detection -- Low fraudulent credential impact - Aggressive Attack: Attacker triggers detection -- Automatic termination of attack capability - Any Attack: Limited to maximum monitoring interval (hours vs. months/years) The mathematical guarantee: attackers cannot maintain indefinite compromise without triggering their own termination for any trust anchor type. This creates optimal security outcomes regardless of attacker behavior patterns. 1.3. Universal Applicability While this specification focuses primarily on PKI Certificate Authorities, the underlying mathematical principles and RTO-Extension mechanism apply universally to all self-signed trust anchors: - DNSSEC Key Signing Keys (KSKs) - Code Signing Root Authorities - Government and National Security PKI systems - Industrial Control System (SCADA/ICS) trust anchors - Mobile Platform Root Authorities (iOS/Android) - Aviation and Transportation PKI systems - Automotive trust anchors (V2X communications) - Financial system root authorities Jahnke Expires November 30, 2025 [Page 5] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 - Healthcare and medical device PKI systems - Emergency service communication trust anchors The universal nature of the mathematical solution demonstrates that this specification addresses a fundamental architectural problem affecting all critical internet infrastructure, not merely PKI systems. 1.4. Backward Compatibility The RTO-Extension is designed to be backward compatible with existing PKI infrastructure and other trust anchor systems. Legacy systems that do not recognize the extension will continue to operate normally until the trust anchor issues its final self-revocation signal. 1.5. Design Philosophy This extension prioritizes mathematical security over operational secrecy for all trust anchor types: FUNDAMENTAL PRINCIPLE: Security MUST NOT depend on information hiding or access restrictions. All security properties MUST derive from cryptographic primitives and established trust relationships consistent for all trust anchor systems. OPERATIONAL CONVENIENCES: - URL encryption prevents casual discovery during audits - Standardized formats improve implementation consistency - Clear documentation reduces deployment errors SECURITY BOUNDARIES: - Private key possession (cryptographically enforced) - Signature verification (mathematically provable) - Dual-person authorization (procedurally enforced) This design ensures security even when ALL operational details are fully disclosed to potential attackers in any trust anchor system. 2. Conventions Used in This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. Terminology Certificate Authority (CA): An entity that issues digital certificates. Root CA: A self-signed CA at the top of a certificate hierarchy. Jahnke Expires November 30, 2025 [Page 6] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 Trust Anchor: Any self-signed cryptographic root of trust used in critical internet infrastructure. RTO-Extension: The Root-TurnOff Extension defined in this specification. A certificate extension containing information necessary for the trust anchor to detect compromise signals. Self-Revocation Signal: An external indicator that may trigger the trust anchor's emergency response procedures. Root-TurnOff CRL: A Certificate Revocation List (CRL) containing the CA's own certificate serial number, effectively turning off the CA's authority. Used specifically for PKI Certificate Authorities. Root-TurnOff Signal: A cryptographically signed message containing the trust anchor's own identifier, effectively terminating the trust anchor's authority in all dependent systems. This is the universal term applicable to all trust anchor types. Monitoring URL: A network location monitored by the trust anchor for potential compromise signals. Dual Person Control (DPC): Security procedure requiring two authorized individuals to complete critical operations. Emergency Signing Key: A cryptographic key used exclusively for authenticating compromise signals, separate from the trust anchor private key. Mathematical Paradox: The circular dependency where trust anchor revocation requires cryptographic proof from a higher authority, but trust anchors are by definition self-signed with no higher authority. DNSSEC KSK: DNS Security Key Signing Key used to sign DNS zone signing keys. Code Signing Root: A trust anchor used to verify software, firmware, or application authenticity. Government Root: A trust anchor used for national or agency-level secure communications. Industrial Root: A trust anchor used in SCADA, ICS, or critical infrastructure control systems. Mobile Platform Root: A trust anchor used by mobile device manufacturers or platform operators. 4. Problem Statement Jahnke Expires November 30, 2025 [Page 7] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 4.1. Current Trust Infrastructure Vulnerabilities Existing trust infrastructure in multiple critical domains suffers from several operational limitations when trust anchors are compromised: - No automated mechanism for rapid compromise detection in any critical infrastructure domain - Manual trust store updates can take months or years in all affected systems - Continued fraudulent credential issuance during cleanup periods for all trust anchor types - No standardized method for emergency trust anchor termination in any critical infrastructure 4.2. The Mathematical Impossibility Consensus The security community in all critical infrastructure domains has historically considered trust anchor self-revocation mathematically impossible due to the circular dependency: revoking any trust anchor requires cryptographic proof from a higher authority, but trust anchors are by definition self-signed with no higher authority. This consensus is documented in security forums and academic literature as an accepted limitation requiring manual coordination taking months or years to propagate globally. As one Stack Overflow security expert summarized: "A root CA being self-issued, it cannot be revoked. A root CA, by definition, is trusted a priori, not because its certificate was signed by some higher-placed CA in the hierarchy. Thus, there is nobody to emit revocation information that would be authoritative on that CA." This limitation applies identically to all self-signed trust anchors. DNSSEC root KSKs cannot be revoked without manual recursive resolver updates; Code Signing Roots cannot be revoked without manual platform updates; Government PKI roots cannot be revoked without manual agency coordination; Industrial Control System trust anchors cannot be revoked without manual facility updates. Microsoft's PKI documentation acknowledges this reality: "root CA certificates are not checked for revocation at all. Such cases (root CA revocation) are handled differently, using OOB [out-of-band] processes" which require manual coordination between browser vendors, operating system vendors, and application developers. Similar limitations exist for all trust anchor systems. 4.3. 25-Year Evolution of an "Unsolvable" Problem The trust anchor revocation problem has been recognized since the early days of cryptographic trust system deployment (1995-2000). Jahnke Expires November 30, 2025 [Page 8] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 Despite numerous high-profile compromises in multiple domains, no standardized solution has emerged in any critical infrastructure domain because the mathematical paradox appeared insurmountable. Manual coordination remained the only viable approach, creating predictable multi-month vulnerability windows for every compromise incident in any critical infrastructure. This specification introduces the first cryptographically sound solution to enable rapid trust anchor self-termination in all critical infrastructure domains, transforming a 25-year-old architectural limitation into a manageable operational procedure. 4.4. Universal Trust Anchor Problem Analysis Analysis in multiple critical infrastructure domains reveals identical mathematical paradoxes: PKI ROOT CA PARADOX: - Self-signed certificate - No higher authority to revoke - Manual trust store updates required - Months/years exposure during manual coordination DNSSEC ROOT KSK PARADOX: - Self-signed trust anchor - No higher authority to revoke - Manual recursive resolver updates required globally - Months/years exposure during manual coordination CODE SIGNING ROOT PARADOX: - Self-signed authority - No higher platform authority to revoke - Manual platform updates required - Months/years exposure during manual coordination GOVERNMENT PKI ROOT PARADOX: - Self-signed national authority - No higher government authority to revoke - Manual agency coordination required - Months/years exposure during manual coordination INDUSTRIAL CONTROL SYSTEM PARADOX: - Self-signed critical infrastructure authority - No higher industrial authority to revoke - Manual system updates required in facilities - Months/years exposure threatening physical safety MATHEMATICAL IDENTITY: All critical infrastructure trust anchors are self-signed with no revocation authority, creating identical mathematical paradoxes requiring identical manual solutions with identical vulnerability windows. Jahnke Expires November 30, 2025 [Page 9] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 4.5. Gap Analysis Current standards in all critical infrastructure domains provide mechanisms for [RFC5280] [RFC6960]: - Subordinate certificate/credential revocation via CRL - Certificate/credential status checking via OCSP or equivalent - Trust anchor management and distribution However, no standard exists in any domain for: - Rapid compromise detection for trust anchor types - Emergency trust anchor self-termination in any domain - Cryptographically secure trust anchor self-revocation in any system - Resolution of the mathematical paradox affecting all domains 5. Solution Overview 5.1. Architecture The self-revocation mechanism consists of four components applicable to all trust anchor types: 1. RTO-Extension: Embedded in trust anchor credentials 2. Monitoring Service: Continuously checks for compromise signals 3. Emergency Signing Key: Separate key for signal authentication 4. Manual Authorization: Human-controlled emergency termination Figure 1: Self-Revocation Operational Flow Normal Operation: +---------------------+ +------------------+ +---------------+ | RTO-Extension |--->| Monitoring |--->| Monitoring | | (in trust anchor) | | Service | | URL | | | | (periodic check) | | (encrypted) | +---------------------+ +------------------+ | (no signal) | +---------------+ Emergency Response: +---------------------+ +------------------+ +---------------+ | Emergency Signal |--->| Monitoring |--->| Emergency | | (signed, detected) | | Service | | Response Team | +---------------------+ | (validates) | | (alerted) | +------------------+ +---------------+ | v +---------------------+ +------------------+ +---------------+ | Root-TurnOff Signal |<---| Manual Signal |<---| Dual-Person | | (Trust Anchor Dies) | | Generation | | Authorization | +---------------------+ +------------------+ +---------------+ This architecture separates automated detection from manual authorization, ensuring rapid response while preventing false positive termination for all trust anchor types. Jahnke Expires November 30, 2025 [Page 10] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 5.2. Solving the "Unsolvable" Mathematical Paradox This specification resolves the mathematical paradox through elegant game-theoretic properties applicable to all trust anchor types. As detailed in Section 1.2, the mathematical guarantee ensures that attackers cannot maintain indefinite compromise without triggering their own termination. Traditional Model: ``` Trust Anchor Compromise = Architecturally impossible to revoke Result: Months/years of continued fraudulent credential capability ``` RTO-Extension Model: ``` Trust Anchor Compromise = Self-Limiting Attack Result: Maximum exposure limited to detection interval (hours) ``` 5.3. Emergency Response Timeline Signal Detection -> Verification -> Authorization -> Distribution (Automated) (Manual) (Manual) (Automated) 0h 15m 45m 1h 2h | | | | | Signal found Team assembly Dual-person Upload to CDP Signature OK Evidence authorization System updates Alert sent verification Signal gen Cache flush Compromise Witness log Verification confirmed complete Maximum Response Time: 2 hours (vs. months for current manual processes for all trust anchor types) Timeline Breakdown: - 0-15min: Monitoring service detects and validates emergency signal - 15-45min: Emergency team assembles, verifies evidence, confirms compromise - 45-60min: Dual-person authorization, manual signal generation - 1-2h: Signal distribution to all endpoints, system updates 5.4. Operational Flow Normal Operation: 1. Trust anchor operates normally with embedded RTO-Extension 2. Monitoring service periodically checks monitoring URL 3. No valid signal present: Trust anchor continues normal operation Emergency Response: 1. Compromise detected by trust anchor operator or external notification 2. Emergency signal created and signed with emergency signing key 3. Monitoring service detects and validates signal Jahnke Expires November 30, 2025 [Page 11] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 4. Automated alert to emergency response team 5. Authorized personnel verify compromise evidence 6. Dual-person authorization for emergency termination 7. Manual creation of self-revocation signal 8. Controlled distribution of revocation signal to all distribution points 9. Trust anchor permanently terminates operations 5.5. Security Properties - Signal detection does not require trust anchor private key - Signal authentication uses separate emergency signing key - Revocation signal generation requires valid trust anchor private key signature - Attackers cannot forge valid Root-TurnOff signals without private key - If attackers have private key, termination limits attack duration - No reliance on external trust relationships - Mathematical security based on established cryptographic verification - Solves the 25-year-old mathematical impossibility problem for all trust anchor types 6. RTO-Extension Definition 6.1. Extension Syntax The RTO-Extension is identified by the following OID: id-ce-selfRevocation OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) ds(5) certificateExtension(29) TBD1 } RFC Editor: Please replace TBD1 with the value assigned by IANA [TBD-IANA]. For enterprise-specific implementations during standardization, private OIDs MAY be used temporarily: Example: 1.3.6.1.4.1.99999.1.99.1 (Enterprise Private Use) Note: This extension is commonly referred to as "RTO-Extension" (Root-TurnOff Extension) in technical documentation and implementations for all trust anchor types. 6.2. Extension Structure SelfRevocationExtension ::= SEQUENCE { version INTEGER { v1(1) } (v1,...), anchorType INTEGER { pki(1), dnssec(2), Jahnke Expires November 30, 2025 [Page 12] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 codeSigning(3), government(4), industrial(5), mobilePlatform(6), aviation(7), automotive(8), financial(9), healthcare(10), emergencyService(11), universal(99) } OPTIONAL, encryptedData SEQUENCE { encryptedURL OCTET STRING, initializationVector OCTET STRING (12), -- 96 bits GCM authenticationTag OCTET STRING (16) -- 128 bits GCM }, keyDerivationSalt OCTET STRING, checkInterval INTEGER OPTIONAL, emergencyContact UTF8String OPTIONAL, signalFormat INTEGER { json(1), xml(2), plain(3) } OPTIONAL, emergencyKeyHash OCTET STRING OPTIONAL -- SHA-256 of emergency public key } 6.3. Extension Semantics anchorType: Indicates the type of trust anchor implementing this extension. This field enables trust-anchor-specific optimization while maintaining universal compatibility. Default value is pki(1) for backward compatibility. encryptedData: Contains AES-256-GCM encrypted monitoring URL with associated cryptographic parameters. The URL MUST use HTTPS and MUST contain sufficient entropy to prevent unauthorized discovery (minimum 384 bits entropy for practical deployment). keyDerivationSalt: Random salt for HKDF-SHA384 key derivation. MUST be cryptographically random with minimum 256 bits entropy. checkInterval: Suggested interval (in seconds) for monitoring the signal URL. Default value is 21600 (6 hours). MUST NOT be less than 3600 (1 hour) for any trust anchor. emergencyContact: Contact information for emergency situations. signalFormat: Expected format of the compromise signal for interoperability. emergencyKeyHash: SHA-256 hash of the emergency signing public key used for signal authentication. Jahnke Expires November 30, 2025 [Page 13] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 6.4. Cryptographic Protection Requirements Trust anchors implementing the RTO-Extension MUST use cryptographically protected monitoring URLs to prevent unauthorized discovery and ensure signal integrity. 6.4.1. URL Encryption Process The monitoring URL MUST be encrypted using AES-256-GCM with the following process: 1. Generate cryptographically random salt (256 bits minimum) 2. Generate cryptographically random IV (96 bits for GCM) 3. Derive encryption key using HKDF-SHA384: - Input Key Material (IKM): Trust anchor public key (DER encoded) - Salt: Random salt from step 1 - Info: "PKI-RTO-URL-v1" || Trust Anchor Subject Key Identifier - Output Length: 32 bytes (256 bits) 4. Encrypt monitoring URL using AES-256-GCM with derived key and IV 5. Store encrypted URL, IV, authentication tag, and salt in extension 6.4.2. URL Decryption Process Trust anchor monitoring services MUST decrypt the monitoring URL using: 1. Extract encrypted data, IV, authentication tag, and salt from extension 2. Derive decryption key using identical HKDF-SHA384 process 3. Decrypt URL using AES-256-GCM with derived key, IV, and tag verification 4. Validate HTTPS URL format and entropy requirements 5. Use decrypted URL for signal monitoring 6.4.3. Security Properties of URL Protection This encryption scheme provides the following security properties: - URL integrity: GCM authentication prevents URL modification - Discovery resistance: Encrypted URLs cannot be trivially extracted - Binding to trust anchor: Key derivation ties URL to specific trust anchor - Signal authentication: Prevents casual false signal placement Note: The encryption provides integrity protection and discovery resistance rather than absolute secrecy, as the decryption key can be derived from the publicly available trust anchor. 6.4.4. URL Protection Design Rationale The RTO-Extension does NOT attempt to provide absolute URL secrecy. Jahnke Expires November 30, 2025 [Page 14] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 The URL encryption serves specific operational purposes: DESIGN GOALS: * Casual Discovery Prevention: Prevent trivial URL extraction * Integrity Protection: GCM authentication prevents tampering * Format Standardization: Consistent encryption across implementations * Audit Trail: Clear crypto parameters for forensic analysis NOT DESIGN GOALS: * Absolute Secrecy: Any party can derive decryption key * Access Control: URL access remains unrestricted when discovered * Security through Obscurity: System security does not depend on URL secrecy RATIONALE: URL discovery by unauthorized parties does not compromise system security, as valid revocation signal generation requires trust anchor private key possession. The encryption serves operational purposes rather than fundamental security isolation. This design choice is intentional and mathematically sound. 6.4.5. URL Entropy Requirements To ensure adequate protection against brute-force discovery, monitoring URLs MUST contain minimum 384 bits of entropy. This requirement can be satisfied through several implementation approaches: EXAMPLE ENTROPY IMPLEMENTATION: High-Entropy Path Generation: Base URL: https://monitoring.example.com/signals/ Random component: 384 bits = 48 bytes = 64 base64url characters Generated path example: /signals/A7B9C2D4E6F8A1B3C5D7E9F2A4B6C8D0E2F4A6B8C0D2E4F6A8B0 C2D4E6F8A0B2C4D6E8F0A2B4C6D8E0F2A4B6C8D0E2F4A6B8C0D2E4F6A8B0/ Calculation: 48 bytes * 8 bits/byte = 384 bits entropy Base64url encoding: 48 bytes = 64 characters (no padding) ALTERNATIVE IMPLEMENTATION: UUID4-based approach (lower entropy but acceptable): Random UUIDs: 3 x UUID4 = 3 x 122 bits = 366 bits entropy Combined path: /signals/uuid1-uuid2-uuid3/ SECURITY NOTE: The 384-bit requirement ensures protection against targeted URL discovery attempts. This entropy level provides approximately Jahnke Expires November 30, 2025 [Page 15] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 2^384 possible URLs, making brute-force discovery computationally infeasible even for nation-state adversaries. 6.5. Emergency Signing Key Management Trust anchors implementing the RTO-Extension MUST establish separate emergency signing keys for signal authentication: 6.5.1. Key Generation and Storage Emergency signing keys MUST be: - Generated separately from trust anchor private keys - Stored in air-gapped systems when not in use - Protected with dual-person control access - Rotated at least every 12 months or immediately upon suspicion - Backed up in geographically separated secure locations 6.5.2. Supported Algorithms The following signature algorithms are RECOMMENDED for emergency keys: - EdDSA (Ed25519): RECOMMENDED for new deployments - RSA-PSS with SHA-384: ACCEPTABLE for existing infrastructure - ECDSA P-384 with SHA-384: ACCEPTABLE for existing infrastructure 6.5.3. Public Key Distribution Emergency signing public keys MUST be: - Included as SHA-256 hash in emergencyKeyHash field - Distributed to monitoring services through secure channels - Verified against the hash before signal validation - Rotated using secure key rollover procedures 6.6. Signal Format Specification To ensure interoperability for all trust anchor types, compromise signals MUST follow a standardized format: 6.6.1. JSON Signal Format (RECOMMENDED) { "version": "1.0", "timestamp": "2025-05-30T10:30:00Z", "anchorType": "pki", "reason": "private-key-compromise", "evidence": "sha384-hash-of-compromise-evidence", "authorizer": "emergency-response-team", "verification": { "algorithm": "EdDSA", "keyReference": "sha256-hash-of-emergency-pubkey", "signature": "base64-encoded-signature" } } Jahnke Expires November 30, 2025 [Page 16] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 6.6.2. XML Signal Format (ALTERNATIVE) 1.0 2025-05-30T10:30:00Z pki private-key-compromise sha384-hash-of-compromise-evidence emergency-response-team base64-encoded-signature 6.6.3. Enhanced Plain Text Signal Format EMERGENCY_REVOCATION_2025-05-30T10:30:00Z_pki_private-key-compromise_ Evidence-Hash:sha384-A7B3C9E1F4D2B8A6C5E7F9D1C3A5B7E9F2D4B6A8C0_ SIGNATURE:base64-encoded-emergency-key-signature Note: The enhanced plain text format now includes evidence hash for forensic traceability and signature verification. 6.7. HSM Compromise and Alternative Signing Scenarios 6.7.1. Primary HSM Compromise Detection When the primary HSM containing the trust anchor private key is suspected of compromise or becomes inaccessible: IMMEDIATE ACTIONS: 1. Activate air-gapped emergency signing capabilities 2. Use pre-distributed emergency authorization tokens 3. Implement manual cryptographic operations if necessary 4. Document all actions with witness verification AIR-GAPPED BACKUP SIGNING: Trust anchors implementing the RTO-Extension SHOULD maintain emergency backup signing capabilities stored in air-gapped environments, activated only during primary HSM compromise scenarios. 6.7.2. Emergency Key Compromise Response When emergency signing keys are suspected of compromise: ESCALATED PROCEDURES: 1. Emergency key rotation MUST be performed immediately 2. All pending signals MUST be re-verified with new keys 3. Historical signal authenticity MUST be re-evaluated 4. Extended monitoring period MUST be implemented 7. Implementation Requirements Jahnke Expires November 30, 2025 [Page 17] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 7.1. Trust Anchor Security Requirements Trust anchors implementing the RTO-Extension MUST meet enhanced security requirements: 7.1.1. Cryptographic Parameters Trust anchors implementing the RTO-Extension MUST use: - RSA key length: 4096 bits minimum (8192 bits RECOMMENDED) - Hash algorithm: SHA-384 minimum (SHA-512 RECOMMENDED) - RTO-Extension: REQUIRED - URL encryption: AES-256-GCM with HKDF-SHA384 (REQUIRED) - Monitoring interval: Maximum 6 hours (REQUIRED) 7.1.2. Operational Security Trust anchors MUST implement: - Dual person control for all private key operations - Hardware Security Module (HSM) protection for private keys - Comprehensive audit logging of all operations - Regular security assessments and penetration testing - Incident response procedures with defined roles 7.1.3. Hardware Security Module Requirements Trust anchors implementing the RTO-Extension MUST use HSMs meeting: - FIPS 140-3 [FIPS140-3] Level 3 minimum certification - Dual-person control for all signature operations - Tamper-evident audit logging capabilities - Emergency key destruction procedures - Authenticated firmware with verified boot process 7.2. Emergency Key Infrastructure Trust anchors implementing the RTO-Extension MUST establish robust emergency key management: 7.2.1. Key Generation Emergency signing keys MUST be: - Generated using certified random number generators - Created in air-gapped environments - Witnessed by authorized personnel during generation - Immediately stored in secure hardware tokens 7.2.2. Key Storage and Access Emergency keys MUST be: - Stored in geographically separated locations - Protected with dual-custody access controls - Regularly tested for integrity and availability - Backed up using secure key escrow procedures Jahnke Expires November 30, 2025 [Page 18] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 7.2.3. Key Rotation Emergency keys MUST be: - Rotated at least every 12 months - Immediately rotated upon suspected compromise - Replaced using secure key rollover procedures - Verified for proper function before activation 7.3. Trust Anchor Implementation Requirements Trust anchors implementing the RTO-Extension MUST: - Include the encrypted RTO-Extension in trust anchor credentials - Implement monitoring service for the decrypted monitoring URL - Maintain dual-person control for emergency procedures - Generate valid revocation signal only with proper authorization - Distribute revocation signal to all dependent systems - Implement secure private key destruction procedures - Maintain baseline revocation list generation for normal operations - Ensure monitoring service availability (99.99% uptime minimum with georedundant deployment) 7.4. High-Availability Monitoring Requirements The monitoring infrastructure MUST meet enhanced availability requirements to ensure reliable compromise detection: UPTIME REQUIREMENTS: - Primary monitoring: 99.99% uptime minimum - Georedundant deployment across minimum 3 geographic regions - Automatic failover between monitoring endpoints - Load balancing across multiple monitoring servers MONITORING REDUNDANCY: - Multiple independent monitoring endpoints - Cross-verification between monitoring systems - Automated health checking of monitoring infrastructure - Real-time alerting for monitoring system failures 7.5. Legacy System Compatibility Trust anchors implementing the RTO-Extension MUST provide fallback mechanisms for legacy systems that do not support RTO-Extension: FALLBACK MECHANISMS: - Traditional CRL/OCSP responders remain operational - Standard revocation checking for non-RTO-aware clients - Gradual migration path for legacy infrastructure - Backward-compatible trust anchor termination procedures LEGACY COORDINATION: When RTO-Extension triggers trust anchor termination, operators MUST simultaneously: Jahnke Expires November 30, 2025 [Page 19] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 - Notify trust store operators via established procedures - Issue traditional revocation notifications - Coordinate with platform vendors for manual trust anchor removal - Maintain communication with legacy system operators 7.6. Automation Prohibition Trust anchors implementing the RTO-Extension MUST NOT automate Root-TurnOff signal generation to prevent catastrophic false positive scenarios. 7.6.1. REQUIRED Manual Processes The following processes MUST be performed manually: - Human verification of compromise evidence - Dual-person authorization (minimum 2 authorized staff) - Manual revocation signal generation with witness protocol - Manual distribution with verification checkpoints - Documented decision trail with digital signatures 7.6.2. FORBIDDEN Automated Processes The following processes MUST NOT be automated: - Automatic revocation signal generation upon signal detection - Script-based emergency procedures without human oversight - Unattended activation mechanisms - Single-person emergency authorization workflows 7.6.3. Rationale for Manual Control False positive Root-TurnOff signal generation represents catastrophic operational risk affecting millions of credentials and critical infrastructure. The gravity of trust anchor termination demands human judgment and dual-person control consistent with existing operational standards and regulatory requirements in all critical infrastructure domains. Historical precedent: No critical infrastructure system (nuclear, military, aviation) implements fully automated emergency shutdown without human oversight and dual-person authorization. 8. Operational Procedures 8.1. Normal Operations During normal trust anchor operations: 1. Trust anchor operates normally with embedded RTO-Extension 2. Monitoring service checks monitoring URL at configured interval 3. No valid signal present: Trust anchor continues normal operation 4. Log monitoring activities for audit purposes 5. Maintain monitoring service availability and redundancy Jahnke Expires November 30, 2025 [Page 20] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 6. Update baseline revocation lists according to operational requirements 7. Rotate emergency keys according to schedule 8.2. Signal Detection and Verification When monitoring service detects a potential compromise signal: 1. Automated download and format validation of signal 2. Emergency key signature verification against known public key 3. Signal timestamp and freshness validation 4. Preliminary assessment of signal authenticity 5. Automated alert to emergency response team 6. Documentation of detection event with complete audit trail 8.3. Emergency Authorization Process Upon valid signal verification: 1. Assembly of minimum two authorized personnel 2. Review of compromise evidence referenced in signal 3. Verification of emergency authorization credentials 4. Independent confirmation of compromise through additional sources 5. Dual-person approval for Root-TurnOff signal generation 6. Documentation of authorization decision with digital signatures 8.4. Manual Signal Generation For authorized emergency termination: 1. Physical presence of both authorized personnel required 2. Secure access to trust anchor private key (HSM dual-key procedure) 3. Manual generation of Root-TurnOff signal containing trust anchor identifier 4. Verification of signal format and digital signature 5. Secure logging of signal generation with witness attestation 6. Creation of multiple copies for distribution redundancy 8.5. Distribution and Verification Following Root-TurnOff signal creation: 1. Manual distribution to all dependent systems 2. Verification of successful propagation to all endpoints 3. Update of status responders with revocation status 4. Cache invalidation commands to all distribution endpoints 5. Notification to system operators 6. Monitoring of client adoption and response 7. Documentation of distribution completion 8.6. Post-Revocation Procedures After successful self-revocation: Jahnke Expires November 30, 2025 [Page 21] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 1. Secure destruction of all trust anchor private key material 2. Destruction of emergency signing keys 3. Coordination with system operators for trust anchor removal 4. Communication to affected credential holders 5. Public notification of trust anchor termination 6. Establishment of successor trust anchor infrastructure if required 7. Comprehensive post-incident analysis and documentation 8. Regulatory notification as required by jurisdiction 9. Security Considerations 9.1. Fundamental Security Principle The core security principle of the RTO-Extension is mathematically sound: trust anchor termination can only be triggered by entities possessing the trust anchor's private key for revocation signal generation. This creates a security model where compromise attempts become self-limiting, solving the 25-year-old mathematical paradox of trust anchor revocation in all critical infrastructure domains. 9.2. Threat Model Analysis 9.2.1. Attacker Without Trust Anchor Private Key If an attacker gains access to trust anchor infrastructure but not the private key, they cannot: - Generate valid revocation signal (requires private key signature) - Forge self-revocation signals (requires emergency key signature) - Cause trust anchor termination through false signals (requires human verification) - Issue valid credentials (existing limitation for all trust anchor types) Impact: No security degradation beyond current standards for any trust anchor type. The RTO-Extension provides no additional attack surface. 9.2.2. Attacker With Emergency Signing Key Only If an attacker gains access to emergency signing keys but not the trust anchor private key, they can: - Create valid compromise signals - Trigger emergency response procedures - Cause operational disruption through false alarms But they cannot: - Generate valid Root-TurnOff signal (requires trust anchor private key) - Actually terminate the trust anchor without human authorization - Bypass dual-person control procedures Impact: Operational disruption but no security compromise. Regular key rotation limits exposure duration. Jahnke Expires November 30, 2025 [Page 22] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 9.2.3. Attacker With Trust Anchor Private Key If an attacker gains access to the trust anchor private key, they can: - Issue fraudulent credentials (existing vulnerability for all trust anchor types) - Generate valid Root-TurnOff signal (beneficial security outcome) - Process legitimate self-revocation signals (beneficial outcome) Analysis: In this scenario, the attacker triggering the turnoff mechanism produces an optimal security outcome. The alternative (attacker having private key but not triggering turnoff) would result in indefinite credential fraud capability. As detailed in Section 1.2, the mathematical guarantee ensures that attackers cannot maintain indefinite compromise without triggering their own termination. This creates optimal security outcomes regardless of attacker behavior patterns for all trust anchor types. Impact: Attack duration limited to maximum check interval versus months/years under current standards in all critical infrastructure domains. 9.2.4. Economic Incentive Analysis Attackers who obtain trust anchor private keys typically seek to: - Issue fraudulent credentials for profit - Maintain long-term access for ongoing exploitation - Avoid detection to maximize return on investment The RTO-Extension creates an economic disincentive for attackers to trigger termination, as doing so immediately destroys their ability to monetize the compromise. However, if termination is triggered, it represents the optimal damage limitation scenario for all trust anchor types. 9.3. Operational Security Organizations implementing the RTO-Extension should: - Implement robust access controls for signal infrastructure - Maintain secure backup and recovery procedures - Establish comprehensive emergency contact procedures - Conduct regular testing of detection procedures (not termination) - Monitor signal infrastructure availability and integrity - Implement comprehensive audit logging for all operations 9.4. Privacy and Confidentiality The encrypted self-revocation URL is embedded in publicly accessible trust anchor credentials. Organizations should: - Use AES-256-GCM encryption for URL protection Jahnke Expires November 30, 2025 [Page 23] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 - Implement appropriate access logging on monitoring endpoints - Ensure URL encryption parameters are properly managed - Consider URL rotation strategies for enhanced security - Monitor for unauthorized access attempts Privacy Impact: URL encryption prevents casual observation of monitoring infrastructure while allowing authorized monitoring services to function correctly. 9.5. Cryptographic Security The security of the RTO-Extension relies on: - Asymmetric cryptography (RSA/ECDSA) for revocation signal signatures - Emergency key signatures for signal authentication - Trust anchor private key secrecy (same assumption as existing systems) - Symmetric encryption (AES-256-GCM) for URL protection - No additional cryptographic assumptions beyond current trust anchor systems Key Insight: The RTO-Extension does not weaken existing security in any scenario for any trust anchor type. It either maintains current security levels (when private key is secure) or significantly improves them (when private key is compromised). 9.6. Cross-Domain Security Considerations Implementation for multiple trust anchor types introduces additional security considerations: 9.6.1. Trust Anchor Type Identification The anchorType field enables domain-specific optimizations while maintaining universal security properties. Incorrect anchorType values do not compromise security but may reduce operational efficiency. 9.6.2. Cross-Domain Attack Vectors Attackers may attempt to leverage compromises in multiple trust anchor types. The RTO-Extension provides independent protection for each trust anchor, preventing compromise propagation between domains. 9.6.3. Coordination Between Trust Anchor Types Emergency responses may require coordination between multiple trust anchor operators. The standardized signal format and procedures enable consistent response in all critical infrastructure domains. 9.7. Frequently Misunderstood Design Decisions Jahnke Expires November 30, 2025 [Page 24] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 9.7.1. "Why can anyone decrypt the URL?" The URL encryption key can be derived by any party possessing the trust anchor credential (which is public). This is INTENTIONAL design: - Monitoring services need URL access without private key possession - Security does not rely on URL secrecy - False signals cannot cause harm without private key - Discovered URLs create no additional attack surface 9.7.2. "Isn't this security through obscurity?" NO. The security model relies on: - Cryptographic signature verification (RSA/ECDSA) - Private key possession requirements - Dual-person authorization procedures - Mathematical impossibility of signal forgery URL obfuscation is an operational convenience, not a security boundary. 9.7.3. "What if attackers find all monitoring URLs?" IRRELEVANT. Attackers discovering monitoring URLs can: - Set false signals (harmless without emergency key signature) - Monitor trust anchor status (information already public) - DoS monitoring infrastructure (operational issue, not security breach) Attackers CANNOT: - Force valid Root-TurnOff signal generation without private key - Bypass dual-person authorization requirements - Forge cryptographically valid signatures The system remains mathematically secure regardless of URL discovery for all trust anchor types. 9.7.4. "What about false positive termination?" False positive termination is prevented by: - Emergency key signature requirement for valid signals - Dual-person authorization for all signal generation - Human verification of compromise evidence - Comprehensive audit trails for accountability The probability of false positive termination approaches zero with proper implementation of manual controls for all trust anchor types. 10. IANA Considerations Jahnke Expires November 30, 2025 [Page 25] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 10.1. Object Identifier Allocation This document requests IANA to allocate an object identifier for the RTO-Extension under the Certificate Extensions arc: id-ce-selfRevocation OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) ds(5) certificateExtension(29) TBD1 } RFC Editor: Please replace TBD1 with the value assigned by IANA [TBD-IANA]. 10.2. RTO-Extension Registry IANA is requested to create a new registry for RTO-Extension parameters: Registry Name: Trust Anchor RTO-Extension Parameters Registration Procedure: Specification Required with Expert Review Reference: This document Initial registry entries: - Version numbers (1-255) - Anchor type identifiers (1-255) - Signal format identifiers (1-255) - Cryptographic algorithm identifiers 10.3. Signal Format Registry IANA is requested to create a registry for standardized signal formats: Registry Name: Trust Anchor Self-Revocation Signal Formats Registration Procedure: First Come First Served Reference: This document Initial formats: - JSON (1): Structured signal with metadata - XML (2): Structured signal in XML format - Plain (3): Simple text-based signal 10.4. Trust Anchor Type Registry IANA is requested to create a registry for trust anchor types: Registry Name: Trust Anchor Self-Revocation Types Registration Procedure: Specification Required with Expert Review Reference: This document Initial anchor types: - PKI (1): Public Key Infrastructure Certificate Authorities - DNSSEC (2): DNS Security Key Signing Keys - Code Signing (3): Software/firmware signing authorities Jahnke Expires November 30, 2025 [Page 26] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 - Government (4): National/agency PKI systems - Industrial (5): SCADA/ICS trust anchors - Mobile Platform (6): Device manufacturer authorities - Aviation (7): Air traffic control and aircraft communication CAs - Automotive (8): Vehicle-to-vehicle/infrastructure communication CAs - Financial (9): Banking and payment system trust anchors - Healthcare (10): Medical device and healthcare record CAs - Emergency Service (11): First responder communication CAs - Universal (99): Generic trust anchor implementation 11. Deployment Considerations 11.1. Migration Timeline Implementation of RTO-Extensions should follow a measured deployment timeline for all trust anchor types: Phase 1 (Months 1-6): Specification finalization and tooling development - Complete IETF standardization process - Develop reference implementations for all trust anchor types - Create testing and validation tools - Establish certification procedures Phase 2 (Months 7-12): Pilot deployments with early adopter organizations - Limited deployment with volunteer operators in all domains - Real-world testing in controlled environments - Feedback collection and specification refinement - Training development for operational staff Phase 3 (Months 13-24): Broader implementation and testing - Wider adoption by progressive organizations in all domains - Integration with existing infrastructure for all trust anchor types - Comprehensive interoperability testing - Development of best practices documentation 11.2. Backward Compatibility Strategy During deployment for all trust anchor types: - Legacy systems will ignore unknown extensions (standard behavior) - Revocation processing remains fully compatible with existing implementations - Status checking integration maintains current protocol compliance - Gradual adoption does not disrupt existing operations - Monitoring can be implemented without affecting credential issuance LEGACY SYSTEM FALLBACK: For systems that do not support RTO-Extension, trust anchors MUST maintain traditional revocation mechanisms: Jahnke Expires November 30, 2025 [Page 27] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 - Standard CRL distribution for PKI systems - OCSP responders for real-time status checking - Manual notification procedures for critical infrastructure - Coordination with trust store operators 11.3. Cost-Benefit Analysis Organizations should consider implementation for all trust anchor types: Implementation Costs: - Emergency key infrastructure development: Approximately $25,000 per trust anchor - Monitoring system deployment and maintenance: Approximately $35,000 per trust anchor - Staff training for emergency procedures: Approximately $15,000 per trust anchor - Compliance and audit system updates: Approximately $10,000 per trust anchor Total: Approximately $85,000 per trust anchor Historical Disasters Prevented: - Historical incidents: $50M+ direct losses, 300K+ users affected - Multi-billion dollar industry disruption - Government PKI incidents: Classified communication compromise - Industrial control system incidents: Physical safety threats - Mobile platform incidents: Supply chain compromise affecting billions of devices - Total estimated historical trust anchor disasters: $2-7 billion+ in global economic damage Security Benefits: - Dramatic reduction in compromise exposure time (2 hours vs months) for all trust anchor types - Improved incident response capabilities in all critical infrastructure domains - Enhanced operator confidence for all trust anchor types - Reduced liability exposure from extended compromises - Solving 25-year-old "unsolvable" architectural problems in all critical infrastructure Return on Investment: Approximately 82,000% based on prevented historical damages for all trust anchor types The security benefits significantly outweigh implementation costs for any trust anchor serving critical infrastructure or high-value applications in all domains. 12. References 12.1. Normative References Jahnke Expires November 30, 2025 [Page 28] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 12.2. Informative References [FIPS140-3] National Institute of Standards and Technology, "Security Requirements for Cryptographic Modules", FIPS PUB 140-3, March 2019, . [RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A., Galperin, S., and C. Adams, "X.509 Internet Public Key Infrastructure Online Certificate Status Protocol - OCSP", RFC 6960, DOI 10.17487/RFC6960, June 2013, . [TBD-IANA] IANA, "Object Identifier Arcs", . Appendix A. Implementation Examples A.1. OpenSSL Configuration Example Example OpenSSL configuration for including RTO-Extension: [ ca_extensions ] basicConstraints = critical,CA:TRUE,pathlen:1 keyUsage = critical,keyCertSign,cRLSign subjectKeyIdentifier = hash # RTO-Extension (using temporary private OID) 1.3.6.1.4.1.44954.1.99.1 = ASN1:SEQUENCE:rto_extension [ rto_extension ] version = INT:1 anchorType = INT:1 encryptedData = SEQUENCE:encrypted_data_seq Jahnke Expires November 30, 2025 [Page 29] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 keyDerivationSalt = FORMAT:HEX,OCTETSTRING:9A3C7E0F2D4B8A6C... checkInterval = INT:21600 emergencyContact = UTF8:emergency@example.com signalFormat = INT:1 emergencyKeyHash = FORMAT:HEX,OCTETSTRING:A7B3C9E1F4D2B8A6... [ encrypted_data_seq ] encryptedURL = FORMAT:HEX,OCTETSTRING:4F8A2E1D9C7B6A5E... initializationVector = FORMAT:HEX,OCTETSTRING:2E4A8C6F1D5B9A3C... authenticationTag = FORMAT:HEX,OCTETSTRING:7F3E9A1C5D8B2F4A... A.2. Emergency Response Procedure Example emergency response checklist applicable to all trust anchor types: 1. Signal Detection Verification - [ ] Confirm signal presence at monitoring URL - [ ] Validate signal format and digital signature - [ ] Verify signal timestamp and freshness (< 24 hours) - [ ] Cross-reference with internal security monitoring - [ ] Document detection time and circumstances 2. Emergency Authorization - [ ] Assemble minimum two authorized personnel - [ ] Verify identity of responding personnel (biometric/badge) - [ ] Review evidence referenced in compromise signal - [ ] Obtain independent confirmation of compromise - [ ] Obtain dual authorization for termination - [ ] Document authorization decision with signatures 3. Manual Signal Generation - [ ] Access secure trust anchor environment with dual control - [ ] Verify HSM functionality and key availability - [ ] Generate Root-TurnOff signal with trust anchor identifier - [ ] Verify signal format and digital signature - [ ] Create backup copies for distribution - [ ] Log signal generation with witness signatures 4. Distribution and Cleanup - [ ] Distribute signal to all dependent systems - [ ] Verify propagation to all endpoints - [ ] Update status responders with revocation status - [ ] Invalidate all caches (CDN, browser, application) - [ ] Notify system operators via emergency contacts - [ ] Initiate private key destruction procedures - [ ] Begin successor trust anchor planning if required 5. Post-Incident Activities - [ ] Conduct comprehensive forensic analysis - [ ] Document lessons learned and process improvements - [ ] Update emergency procedures based on experience - [ ] Coordinate with law enforcement if required - [ ] Prepare public disclosure and communication A.3. Cross-Domain Implementation Examples A.3.1. DNSSEC Implementation For DNSSEC KSK implementation, the RTO-Extension would be embedded in KSK metadata and monitored by recursive resolver operators. Upon detection of a valid emergency signal, the KSK would be marked as revoked in the root zone, triggering automatic updates to recursive resolvers globally. A.3.2. Code Signing Implementation Code signing authorities would embed the RTO-Extension in their root certificates. Platform operators (OS vendors, app stores) would monitor for emergency signals and automatically distrust the signing authority upon validated compromise detection. A.3.3. Government PKI Implementation National PKI systems would implement RTO-Extension in all government trust anchors. Agency-wide emergency response procedures would enable rapid compromise response while maintaining appropriate classification levels and operational security. Jahnke Expires November 30, 2025 [Page 30] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 Appendix B. Frequently Asked Questions B.1. Security Questions Q: What if an attacker gains access to the monitoring URL? A: The monitoring URL itself provides no attack capability. Valid self-revocation requires both emergency key signatures for signal authentication and trust anchor private key signatures for actual revocation signal generation. URL discovery does not compromise the cryptographic security model. Q: What if the monitoring infrastructure is compromised? A: Monitoring infrastructure compromise cannot cause trust anchor termination. Valid revocation signals require both emergency key signatures and trust anchor private key signatures, which are stored separately from monitoring infrastructure. Q: How do legacy systems handle RTO-Extension? A: Legacy systems ignore unknown extensions and continue normal operation. Traditional revocation mechanisms (CRL/OCSP) remain functional for backward compatibility. B.2. Implementation Questions Q: What happens during network partitions? A: Monitoring services implement georedundant deployment. Extended network partitions may delay signal detection but cannot cause false revocations due to manual authorization requirements. Q: Can the RTO-Extension be disabled? A: No. Once embedded in a trust anchor, the RTO-Extension cannot be disabled without issuing a new trust anchor. This prevents attackers from disabling the protection mechanism. Q: What about performance impact? A: The RTO-Extension adds minimal overhead. URL monitoring occurs at 6-hour intervals by default, and the extension itself adds less than 1KB to trust anchor size. Appendix C. Test Vectors C.1. URL Encryption Test Vector Input Parameters: - Trust Anchor Public Key (DER): 3082...ABCD (example) - Subject Key Identifier: A1B2C3D4E5F6789A - Salt: 9A3C7E0F2D4B8A6C5E7F9D1C3A5B7E9F2D4B6A8C0E2F4A6B8C0D2E4F6 A8B0C2D4 - IV: 2E4A8C6F1D5B9A3C7E0F2D4B HKDF-SHA384 Key Derivation: - IKM: Trust Anchor Public Key (DER encoded) - Salt: 32-byte salt from above Jahnke Expires November 30, 2025 [Page 31] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 - Info: "PKI-RTO-URL-v1" || Subject Key Identifier - Output: 32-byte encryption key AES-256-GCM Encryption: - Plaintext URL: "https://monitoring.example.com/signals/A7B9C2..." - Key: Derived 32-byte key from HKDF - IV: 12-byte IV from above - Ciphertext: 4F8A2E1D9C7B6A5E... - Authentication Tag: 7F3E9A1C5D8B2F4A... C.2. Emergency Signal Validation Test Vector JSON Signal Example: { "version": "1.0", "timestamp": "2025-05-30T10:30:00Z", "anchorType": "pki", "reason": "private-key-compromise", "evidence": "sha384-B7A9D2F4C6E8A0B3D5F7A9C2E4F6B8D0A2C4E6F8B0D2F4A6 C8E0B2D4F6A8C0E2", "authorizer": "emergency-response-team", "verification": { "algorithm": "EdDSA", "keyReference": "sha256-A7B3C9E1F4D2B8A6C5E7F9D1C3A5B7E9", "signature": "6F2A8C4E0B6D8F2A4C6E8B0D2F4A6C8E0B2D4F6A8C0E2F4A6 B8C0D2E4F6A8B0" } } Signature Verification: - Message: Canonical JSON without "verification" field - Public Key: Ed25519 key corresponding to keyReference hash - Signature: Base64-decoded signature from verification field - Result: Valid/Invalid signature verification Appendix D. Document History D.1. Changes from version -00 to version -01 FUNDAMENTAL SCOPE TRANSFORMATION: - TITLE CHANGE: From "Certificate Authority Self-Revocation Extension" to "Universal Trust Anchor Self-Revocation Extension for Critical Internet Infrastructure" reflecting complete scope expansion - PARADIGM SHIFT: Transformed from PKI-specific solution to universal mathematical solution applicable to all self-signed trust anchors - MATHEMATICAL BREAKTHROUGH: Documented solution to 25-year-old "architecturally impossible" problem affecting all critical infrastructure domains - UNIVERSAL APPLICABILITY: Extended coverage to DNSSEC, Code Signing, Government PKI, Industrial Control Systems, Mobile Platforms, Aviation, Automotive, Financial, Healthcare, and Emergency Services Jahnke Expires November 30, 2025 [Page 32] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 MAJOR STRUCTURAL ADDITIONS: - Restructured Table of Contents with comprehensive subsection enumeration - Consolidated mathematical paradox explanation to Section 1.2 - Moved historical incidents to Appendix E for better flow - Enhanced cross-domain security considerations - Improved terminology consistency (RTO-Extension throughout) - Added comprehensive FAQ and test vectors TECHNICAL ARCHITECTURE ENHANCEMENTS: - EXTENSION STRUCTURE: Added anchorType field with enumeration for all critical infrastructure types - SIGNAL FORMAT: Enhanced JSON/XML formats to include anchorType field for cross-domain interoperability - URL ENCRYPTION: Updated key derivation terminology for consistency - MONITORING REQUIREMENTS: Enhanced from 99.9% to 99.99% uptime with georedundant deployment specifications - GAME-THEORETIC ANALYSIS: Consolidated mathematical proof of optimal security outcomes IMPLEMENTATION GUIDANCE EXPANSION: - OPERATIONAL PROCEDURES: Enhanced for universal applicability while maintaining PKI focus for backward compatibility - FALLBACK MECHANISMS: Added comprehensive legacy system support - EMERGENCY PROCEDURES: Enhanced with air-gapped backup procedures and HSM compromise scenarios - TEST VECTORS: Added concrete examples for URL encryption and signal validation EDITORIAL AND TECHNICAL CORRECTIONS: - TERMINOLOGY CONSISTENCY: Unified use of "RTO-Extension" throughout - ELIMINATED REPETITIONS: Consolidated mathematical explanations - IMPROVED STRUCTURE: Better organization and flow - ENHANCED CLARITY: Simplified complex explanations - CORRECTED FORMATTING: All lines under 72 characters, proper pagination D.2. Implementation Notes This version incorporates comprehensive expert review feedback focusing on technical precision, implementation guidance, and operational procedures. The enhanced specification provides concrete implementation examples, test vectors, and detailed procedures for real-world deployment across all critical infrastructure domains. The universal scope expansion demonstrates that this specification solves fundamental architectural problems affecting all self-signed Jahnke Expires November 30, 2025 [Page 33] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 trust anchors in critical internet infrastructure, not merely PKI systems. This positions the RTO-Extension as a foundational security improvement for the entire internet trust ecosystem. Appendix E. Historical Incident Analysis E.1. Historical Incident Analysis Timeline Analysis: - June 2011: Initial compromise (undetected) - August 29, 2011: Public disclosure - August 30, 2011: Google Chrome emergency update - September 2, 2011: Mozilla Firefox 6.0.1 release - September 9, 2011: Apple Security Update 2011-005 - September 20, 2011: CA declared bankrupt Impact: 531 fraudulent certificates issued for 344 domains including Google, Yahoo, Facebook, and government domains. Over 300,000 Iranian users directly affected. Global trust store cleanup required 3+ weeks for major browsers, with embedded systems remaining vulnerable indefinitely. E.2. Cross-Domain Trust Anchor Vulnerabilities While PKI incidents demonstrate the severity of trust anchor compromise, similar vulnerabilities exist in all critical infrastructure domains: DNSSEC VULNERABILITIES: - Theoretical root KSK compromise would require manual coordination with thousands of recursive resolver operators globally - No automated mechanism for emergency KSK revocation - Extended vulnerability periods during manual updates MOBILE PLATFORM VULNERABILITIES: - Code signing compromises affecting app store integrity - Supply chain attacks through compromised signing certificates - Manual OS update coordination affecting billions of devices GOVERNMENT PKI VULNERABILITIES: - Classified communication compromise through PKI vulnerabilities - Manual agency coordination requirements - National security implications of extended exposure periods INDUSTRIAL CONTROL SYSTEM VULNERABILITIES: - Critical infrastructure compromise through trust anchor vulnerabilities - Manual system update coordination in critical facilities - Physical safety implications of extended exposure periods E.3. DNSSEC Root Key Compromise Analysis While no documented DNSSEC Root Key Signing Key (KSK) compromise has Jahnke Expires November 30, 2025 [Page 34] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 occurred since deployment in 2010, the mathematical impossibility of rapid root key revocation creates a uniquely severe vulnerability profile for global Internet infrastructure. Scope of DNSSEC Root Dependency: - Root KSK validates all Top-Level Domain DNSSEC chains - Compromise enables fraudulent DS record generation for any TLD - All DNSSEC-validating resolvers globally trust compromised signatures - No cryptographic mechanism exists for rapid root key invalidation Manual Remediation Timeline Analysis: Based on the 2018 Root Key Rollover experience: - Planning phase: 2+ years (demonstrated historical requirement) - Implementation coordination: 6-12 months minimum - Global propagation: 6-18 months for complete adoption - Legacy system updates: Indefinite (many systems non-updatable) RTO-Extension Applicability: The universal mathematical solution applies directly to DNSSEC: - Root KSK with embedded RTO-Extension enables cryptographic self-termination - Compromise detection triggers automated emergency response procedures - Maximum exposure limited to monitoring interval (hours vs. years) - Controlled degradation to non-DNSSEC operation vs. indefinite compromise Author's Address Torsten Jahnke Chief Executive Officer Aviontex GmbH - keweonDNS Project Bavaria, Germany Email: torsten.jahnke@aviontex.de URI: https://www.aviontex.de Acknowledgments This work was developed as part of security enhancements for the keweonDNS project at Aviontex GmbH. The authors acknowledge the contributions of the security community in all critical infrastructure domains in identifying the operational gaps that this specification addresses. Special recognition to the XDA-Developers and Android-Hilfe forum communities whose relentless questioning about DNS security edge cases and "worst-case scenarios" led to the fundamental insights enabling this breakthrough. The collaborative security mindset of these mobile development communities proved instrumental in Jahnke Expires November 30, 2025 [Page 35] Internet-Draft Universal Trust Anchor Self-Revocation May 2025 identifying and solving what security experts in all critical infrastructure domains had considered an unsolvable architectural problem for 25+ years. The realization that this mathematical solution applies universally to all self-signed trust anchors demonstrates the power of interdisciplinary thinking and cross-domain security analysis. This specification would not have been possible without the diverse perspectives and relentless questioning that characterize vibrant technical communities. Special thanks to the security researchers and experts in PKI, DNSSEC, government systems, industrial control systems, mobile platforms, and other critical infrastructure domains who provided detailed technical review and identified critical implementation considerations that significantly improved the robustness and universal applicability of this specification. The authors particularly acknowledge the expert review feedback that identified specific implementation requirements, test vector needs, and operational procedure enhancements that transformed this specification from a theoretical solution into a practical, deployable standard for critical internet infrastructure. The historical analysis of trust anchor compromise incidents was informed by public reports from security teams, government agencies, and various academic security researchers who documented the operational challenges in existing trust anchor infrastructure in all critical domains.