]> RustyKey®

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SEC COSE quantum-resistant cryptography post-quantum cryptography isogeny-based cryptography constrained devices verifiable credentials linkable and unlinkable selective disclosure of claims aerospace satellite remote robotic telesurgery IAM IoT security NOTE: This document describes a signature scheme based on the SQIsign algorithm currently under evaluation in the 3rd round NIST Post-Quantum Cryptography standardization process. Be aware that the underlying primitive may change as a result of that process. This document specifies the algorithm encodings and representations for the SQIsign digital signature scheme within the CBOR Object Signing and Encryption (COSE) and JSON Object Signing and Encryption (JOSE) frameworks. SQIsign is an isogeny-based post-quantum signature scheme that provides an unusually compact signature and public key size among candidates of the NIST Post-Quantum Cryptography (PQC) standardization and on-ramp-to-standardization processes. The standardization of SQIsign will be helpful to address current infrastructure bottlenecks, specifically the FIDO2 CTAP2 specification used by many in-service devices. This document clarifies that SQIsign does not expose the auxiliary torsion-point information exploited in the SIDH/SIKE attacks. Consequently, the specific attack techniques of Castryck–Decru do not directly apply. However, the scheme remains subject to ongoing cryptanalysis of isogeny-based constructions. By establishing stable COSE and JOSE identifiers, this document ensures the interoperability required for the seamless integration of post-quantum security into high-density, bandwidth-constrained, and legacy-compatible hardware environments. Status information for this document may be found at . Discussion of this document takes place on the COSE Working Group mailing list (), which is archived at . Subscribe at . Source for this draft and an issue tracker can be found at .

Introduction This document registers algorithm identifiers and key type parameters for SQIsign in COSE and JOSE.

Background and Motivation Post-quantum cryptography readiness is critical for constrained devices. As of late 2026, while FIDO2/WebAuthn supports various COSE algorithms, some hardware authenticators and platform authenticators (like TPMs) have strict memory/storage constraints, effectively limiting public keys to 1024 bytes or less, hindering the adoption of large-key post-quantum algorithms.

Pressing Need: Smaller PQC Signatures FN-DSA (Falcon) and ML-DSA (Dilithium) have larger signatures that may not fit in constrained environments. Depending on authenticator implementation, transport (USB/NFC/BLE), and fragmentation support, many CTAP2 authenticators impose practical limits near 1024 bytes for external key communication — well below CTAP2's own protocol ceiling for message reassembly, commonly cited around 7609 bytes . Post-quantum signature schemes with larger keys or signatures risk pushing messages toward either limit, stressing constrained authenticators and transports. SQIsign-L1, L3, and L5 signatures remain small enough to fit comfortably within both constraints, and are well suited to highly constrained networks such as 802.15.4. The fundamental differences between ML-DSA, FN-DSA, and SQIsign lie in their underlying hard mathematical problems, implementation complexity, and performance trade-offs. Falcon (NIST secondary) uses NTRU lattices to achieve very small signatures and fast verification, but requires complex floating-point math. Dilithium (NIST primary) is a balanced, high-efficiency lattice scheme using Module-LWE/SIS, easy to implement. SQIsign is a non-lattice, isogeny-based scheme that offers an unusually small signature compared to other PQC signature candidates under NIST evaluation, historically at the cost of the most computationally intensive signing operation of the group. SQIsign is an isogeny-based digital signature scheme participating in NIST's Round 3 Additional Digital Signature Schemes, not yet a NIST standard. Early reference implementations, evaluated prior to browser WebAssembly (WASM) and GPU-compute optimization, reported signing times of seconds, not milliseconds even for Level 1 parameters. More recent implementations of actual browser-code variant for WebAuthn PassKey are routinely less than 1 second . As a directly reproducible counter-data-point, the author's SQIsign-L1 WASM implementation, exercised end-to-end as a JWS signing operation, measures a repeatable average of 350ms per signature on consumer device . Since draft v07, we also published npm-installable modules of WebGPU-accelerated variants for L1, L3, and L5, with one critical caveat: any site consuming them MUST be served with crossOriginIsolated:true, without exception. This requires strict COOP/COEP response headers, which in turn unlock SharedArrayBuffer and Atomics for synchronized cross-thread WASM linear-memory access, and restore high-resolution performance.now() timers, which browsers deliberately fuzz even under isolation, to resist timing-based side-channel attacks. Under these conditions signing time is yet faster: median sign time of 155ms per signature (+1 SD 172ms / −1 SD 131ms), on identical hardware and browser. Implementers should treat this isolation requirement as a first-class deployment constraint, not an opt-in optimization. COEP's enforcement mode (require-corp) blocks any cross-origin subresource or embed that does not itself opt in via Cross-Origin-Resource-Policy, a compliant CORS response, or (for framed documents) its own COEP declaration. In practice, at time of writing, this breaks or disables many commonly-deployed commercial integrations that consumers and web-developers otherwise take for granted. Examples of features and services that either stop working or suffer degraded levels of service include: third-party payment flows, most analytics, most ad-tech scripts, and some embedded video-sharing platforms and social-media networks. Site operators adopting these WebGPU-accelerated signing paths should budget for the loss of such "drop-in" third-party functionality, and identify, implement, and test cross-origin-isolation-compatible alternatives, as a pre-deployment task and cost — not an afterthought discovered post-launch.

Reproducibility Both WASM and WASM+WebGPU figures are independently reproducible against the live implementation at the cited testbed, which documents sample size and full measurement methodology. This measurement reflects a high-end consumer platform and should be read as an upper bound on currently-achievable browser performance, not as representative of lower-end mobile devices, older hardware, or the constrained authenticators and platform modules discussed above. Benchmarks on representative mid-tier and mobile hardware are planned and will be published at as they become available. As of this writing, comparable measurements have not been confirmed on Safari, Firefox, or Edge; the WebGPU-accelerated path in particular is expected to vary with each browser's crossOriginIsolated:true enforcement and WebGPU compute-shader support, and should not be assumed portable without independent verification.

Faster signing times needed, compared to NIST-approved alternatives Speed: even at ~350ms (WASM) or ~155ms (WASM with WebGPU-acceleration), SQIsign-L1 signing remains an order of magnitude slower than ML-DSA signing on comparable hardware. Implementers should treat both the early and current figures as implementation-dependent, not intrinsic to the algorithm, and should expect continued improvement as WASM (Node.js backend and browser frontend) and WebGPU-accelerated (browser-only) implementations mature.

Size: the single-most important driver for utility Table 1 compares representative parameter sets; note that these schemes are at different stages of standardization and evaluation. Algorithm Public Key Size Signature Size PK + Sig Fits < 1024? ML-DSA-44 1,312 bytes 2,420 bytes ❌ (3,732 total) ML-DSA-65 1,952 bytes 3,293 bytes ❌ (5,245 total) ML-DSA-87 2,592 bytes 4,595 bytes ❌ (7,187 total) FN-DSA-512 897 bytes 666 bytes ❌ (1,563 total) FN-DSA-1024 1,793 bytes 1,280 bytes ❌ (3,073 total) SQIsign-L1 83 bytes 200 bytes ✅ (283 total) SQIsign-L3 129 bytes 306 bytes ✅ (435 total) SQIsign-L5 169 bytes 406 bytes ✅ (575 total)

Pressing Need: Limit or Stop "Harvest Now, Exploit Later" (HNEL) Attacks Adversaries are collecting encrypted data today to decrypt when quantum computers become available. The transition to post-quantum cryptography (PQC) is critical for ensuring long-term security of digital communications against adversaries equipped with large-scale quantum computers. The National Institute of Standards and Technology (NIST) has been leading standardization efforts, having selected initial PQC algorithms and continuing to evaluate additional candidates. CBOR Object Signing and Encryption (COSE) is specifically designed for constrained node networks and IoT environments where bandwidth, storage, and computational resources are limited. The compact nature of SQIsign makes it an ideal candidate for COSE deployments.

Unprecedented regulatory urgency: move from theoretical planning to legally binding enforcement Regulatory urgency for post-quantum migration is not confined to a single jurisdiction. In the United States, Executive Order 14413 directs the continued acceleration of quantum-resistant cryptography adoption across federal systems and critical infrastructure. This order builds on the algorithm guidance established in , page 4, the use of RSA, Diffie-Hellman (DH), and elliptic curve cryptography (ECDH and ECDSA) when mandated. Outside North America, the United Arab Emirates' National Encryption Policy established national requirements for encryption practice and migration planning as post-quantum algorithms mature and become standardized. In the Asia-Pacific region, Singapore's Cyber Security Agency (CSA), in coordination with the Monetary Authority of Singapore (MAS), issued a Quantum-Safe Migration Handbook that required operators of critical information infrastructure (CII) to submit a full migration plan by March 2027 and complete migration to quantum-resistant encryption by 2031. France, Germany, Italy, the UK, Canada, Japan and the US recently came together and released a joint call to action to governments and organizations to begin their PQC transition as soon as possible to avoid exposure to quantum risks and to provide a level of long-term protection of confidential data. There is now a convergence across independently governed jurisdictions in North America, the Gulf region, and Southeast Asia. "Harvest Now, Exploit Later" is turning into a matter of near-term operational urgency worldwide, driving the need for compact, deployable PQC signature schemes.

Direct performance comparison of SQIsign-L1 over existing NIST-approved algorithms: Verifiable Credentials Selective Disclosure Over Optical, BLE and other Constrained-Bandwidth Channels

Selective-Disclosure Credential Deployments Selective-disclosure credential systems allow a holder to reveal only selected issuer-authenticated claims. The credential format and presentation protocol, rather than the COSE or JOSE signature algorithm alone, determine the resulting privacy properties. For example, an issuer can sign a commitment structure over a set of claims. A holder may disclose a claim together with the information needed to verify that the claim is included in the issuer-signed structure. Depending on the construction, a presentation can include commitment openings, inclusion proofs, issuer identifiers, status information, device authentication, or other protocol-specific data.

Linkable claims selective disclosure Re-use of a static issuer-signed credential structure can permit correlation between presentations. In this disclosure mode, correlation across presentations is required, not merely tolerated. Example: Hazardous-materials ("hazmat") shipping manifests are re-verified by carriers, first responders, and regulators at multiple points along a transport chain; confirming that each checkpoint is looking at the same declared shipment is necessary for safety and audit purposes. Other linkable examples include origin, materials, environmental performance, and recycling claims.

Unlinkable claims selective disclosure Applications requiring presentation unlinkability need a protocol-level construction with an explicit unlinkability definition and threat model. Conventional digital signature schemes, including current PQC signature schemes, do not by themselves provide re-randomizable zero-knowledge presentations of signed claims. Correlation across presentations is not required or wanted. Mobile driving licenses (mDLs) , as specified in , is the clearest example: a holder must not be traceable across unrelated age- or identity-verification events, even by colluding verifiers. Classical algorithms (pre-PQC) like BBS/BBS+ solve this natively and efficiently: a single signature supports an unbounded number of statistically independent, re-randomizable zero-knowledge proofs over the same underlying claims. It is unsuitable for PQC deployment, however, for a reason distinct from unlinkability itself: BBS/BBS+ security rests on pairing-friendly elliptic curves. Elliptic curves are broken by Shor's algorithm, so unforgeability -- not merely unlinkability -- collapses against a quantum adversary. BBS/BBS+ is therefore excluded from consideration entirely, not merely deprioritized. Some designs may issue multiple independently usable issuer-authenticated artifacts to a holder, for example the new Digital Product Passport . In such designs, compact signatures can reduce issuance bandwidth, holder storage, and presentation size. The benefit is especially relevant where credentials are transferred using constrained channels, such as QR codes, NFC, BLE, or low-bandwidth networks. Under this pattern, per-presentation cost scales as:

This multiplication is tractable at any scale only with a small per-signature size. Table 2 summarizes which combination of approach and algorithm remains viable as claim count grows: Disclosure mode Viable algorithm(s) Constraint Linkable (any claim count) FN-DSA, ML-DSA, or SQIsign, any level Signature cost paid once; size doesn't scale with claims Unlinkable, small claim count ML-DSA-/FN-DSA-class, or SQIsign-L1 Tractable only while claims x batch depth stays small Unlinkable, large claim count SQIsign-L1 ML-DSA-/FN-DSA-class signature sizes make claims x batch depth x sig-size prohibitive; SQIsign-L1's compact size enables it to emerge as one of few quantum-resistant algorithm options suitable for verifiable credentials 'unlinkable' selective disclosure This document does not define a selective-disclosure credential format, unlinkability mechanism, commitment scheme, revocation mechanism, or presentation protocol. Such mechanisms are application- and ecosystem-specific, and nothing in this section shall diminish the applicability of FN-DSA or ML-DSA for linkable selective disclosure, or wherever NFC, fast-BLE, or other non-optical transports are available.

Scope and Status This document specifies interoperable COSE and JOSE representations for a defined version of SQIsign. It does not make an independent determination of the cryptographic suitability of SQIsign. This document is published on the Standards track rather than Informational track. This document does not represent Working Group consensus on algorithm innovation. The COSE and JOSE working groups focus on algorithm integration and encoding, not cryptographic algorithm design. The cryptographic properties of SQIsign are being evaluated through NIST's process and academic peer review. If a WG wishes to pursue this as Standards Track, the document's strongest justification is a stable, precise, interoperable encoding specification, motivated by: Algorithm Maturity: SQIsign is currently undergoing evaluation in NIST's on-ramp process Continued Cryptanalysis: variations continue to be developed either reducing signature size or speeding up signing time not only by implementers (who try to avoid affecting cryptanalysis) by the cryptographic research community, including the IRTF CFRG High anticipated demand: This specification enables experimentation and early deployment to gather implementation experience

Relationship to Other Work This document follows the precedent established by and for integrating NIST PQC candidate algorithms into COSE and JOSE. The structure and approach are intentionally aligned to provide consistency across post-quantum signature scheme integrations.

Constrained Device Applicability SQIsign is particularly attractive for: QR code printers, any display screen, scanners especially mobile consumer-grade IoT sensors with limited flash memory Firmware updates over low-bandwidth networks (LoRaWAN, NB-IoT) Embedded certificates burned into the OS, or added to the secure enclave of a constrained device Blockchain and DLT where transaction size affects gas fees Satellite communications with bandwidth constraints

Conventions and Definitions 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 when, and only when, they appear in all capitals, as shown here. This document uses the following terms: PQC: Post-Quantum Cryptography COSE: CBOR Object Signing and Encryption JOSE: JSON Object Signing and Encryption JWS: JSON Web Signature JWK: JSON Web Key CBOR: Concise Binary Object Representation ECDH: Elliptic Curve Diffie-Hellman IANA: Internet Assigned Numbers Authority

Cryptanalytic Resistance: SIDH/SIKE Attacks Do Not Apply

SIKE Vulnerability (The "Torsion Point" Attack) of 2022 SIKE (Supersingular Isogeny Key Encapsulation) was a key exchange, more specifically, a Key Encapsulation Mechanism (KEM). In the SIKE protocol, users had to share more than just the target elliptic curve. To make the math work for key exchange, they shared the images of specific points (called torsion points) under the secret isogeny. The Info: If the secret isogeny is 𝜙, SIKE gave away 𝜙(𝑃) and 𝜙(𝑄) for specific basis points 𝑃 and 𝑄. The Break: In 2022, Castryck and Decru showed that this auxiliary information allowed an attacker to allowed an attacker to construct a higher-dimensional abelian variety linking the public data. In this setting, the secret isogeny can be recovered efficiently using techniques based on Kani’s results on isogenies between products of elliptic curves. The Oversight: For years, cryptanalysts thought this extra info was harmless. Related techniques existed in the algebraic geometry literature but had not previously been applied in this cryptographic context.

Why SQISign appears unaffected by the SIKE Vulnerability SQIsign is a signature scheme in which the prover demonstrates knowledge of an isogeny through a zero-knowledge protocol. Unlike SIDH/SIKE, it does not publish images of torsion basis points under secret isogenies. Castryck–Decru attack relies critically on this auxiliary torsion-point information to construct additional structure (e.g., via abelian surfaces) that enables efficient recovery of the secret isogeny. SQIsign does not provide such auxiliary data, so these techniques do not directly apply. Attacks would instead need to solve instances of the isogeny path problem or related problems in the endomorphism ring, for which no comparable shortcut is currently known.

SQIsign Algorithm Overview

Cryptographic Foundation SQIsign is based on the hardness of finding isogenies between supersingular elliptic curves over finite fields. The security assumption relies primarily on the difficulty of the Isogeny Path Problem Unlike lattice-based schemes, isogeny-based cryptography offers: Smaller key and signature sizes Algebraic structure based on elliptic curve isogenies Different security assumptions (diversification from lattice-based schemes)

Security Levels SQIsign is defined with three parameter sets corresponding to NIST security levels: Parameter Set NIST Level Public Key Signature Quantum Security (estimated) SQIsign-L1 I 83 bytes 200 bytes ~128 bits SQIsign-L3 III 129 bytes 306 bytes ~192 bits SQIsign-L5 V 169 bytes 406 bytes ~256 bits

Performance Characteristics Signing: Computationally intensive relative to lattice schemes in unoptimized reference code; substantially faster in optimized WASM/WebGPU browser implementations (see ). Verification: Moderate computational cost Key Generation: Intensive computation required Size: Exceptional efficiency: substantially smaller than many lattice-based alternatives at comparable security levels Recommended Use Cases: - Sign-once, verify-many scenarios (firmware, certificates) - Bandwidth-constrained environments - Storage-limited devices - Applications where signature/key size dominates performance considerations

SQIsign Variants and the Post-SIKE Landscape While the SQIsign team initially focused on improving the core algorithm, the 2022 SIKE vulnerability catalyzed broader research into higher-dimensional algebraic geometry, particularly investigating improvements to key and signature generation speed—widely viewed as implementation bottlenecks. This interest has sparked an evolution of SQIsign variants, all still based on the baseline algorithm currently competing in NIST's Round 3. Remarkably, two independent groups published dimension-2 variants on the same day (May 13, 2024), with a third appearing the following day—demonstrating the rapid, simultaneous evolution of the field following the 2022 SIKE breakthrough. Given this dynamic environment, readers interested in SQIsign's future will benefit from this summary, which we intend to update with each revision of this standards-track submission. The key takeaway is that researchers have repurposed the higher-dimensional techniques from the SIKE cryptanalysis to optimize SQIsign variants with faster signing and potentially smaller sizes, while each group attempts to maintain equivalent post-quantum security levels. Variants can be classified primarily by the geometric dimensions they employ:

Core SQIsign (Dimension 1) The baseline algorithm currently competing in NIST's Round 3. The SQIsign team, in cooperation with IBM researchers, actively maintains and tunes this version. Recent updates focus on reducing memory footprints and accelerating core algebraic operations for practical implementation. However, NIST's current process permits only minor "tweaks" rather than substantial algorithmic changes.

Multi-dimensional variants SQIsignHD dramatically shrunk signature sizes, simplified verification. SQIsign2D-West prioritized a rigorous security proof over raw speed. SQIsign2D-East fast 2D verification using a generalized random isogeny algorithm. SQIPrime : Offers two sub-variants with different dimension trade-offs: SQIPrime2D: Uses only dimension 2 non-smooth challenge isogenies, avoiding the dimension 4 computations required by SQIsignHD. More efficient while remaining highly compact compared to non-isogeny PQC schemes. SQIPrime4D: Uses dimension 4 isogenies for response representation, prioritizing maximum compactness at the cost of exponentially higher runtime. Despite the paper's title, this sub-variant represents the authors' exploration before settling on the 2D approach.

COSE Integration This section defines the identifiers for SQIsign in COSE . This section defines identifiers and parameters for representing SQIsign keys and signatures in COSE , including a new COSE key type, key-type-specific key parameters, and algorithm identifiers to be registered in the IANA "COSE Algorithms" registry .

SQIsign Algorithms This document defines the following COSE algorithm identifiers. Values are suggested for early allocation and are subject to confirmation by IANA (see IANA Considerations). Name Description Value (TBD) SQIsign-L1 SQIsign, NIST PQC Security Category 1 -61 SQIsign-L3 SQIsign, NIST PQC Security Category 3 -62 SQIsign-L5 SQIsign, NIST PQC Security Category 5 -63

SQIsign Key Types A new COSE key type is defined for SQIsign, with the name "SQIsign" and value TBD-KTY, to be assigned from the IANA "COSE Key Types" registry.

SQIsign Key Parameters SQIsign keys use the COSE_Key common parameters defined in , with the following specific assignments: The kty parameter (label 1) MUST be TBD-KTY (see the RFC Editor note below). The alg parameter (label 3) MUST be -61 (SQIsign-L1), -62 (SQIsign-L3), or -63 (SQIsign-L5). Byte lengths for each parameter set are taken from the SQIsign specification Version 3.0 (2026-09-01) and the nist-v3 reference C (CRYPTO_PUBLICKEYBYTES, CRYPTO_SECRETKEYBYTES, CRYPTO_BYTES): Parameter set NIST level Public key Private key Signature SQIsign-L1 (p324_3) I 83 bytes 270 bytes 200 bytes SQIsign-L3 (p500_27) III 129 bytes 417 bytes 306 bytes SQIsign-L5 (p664_17) V 169 bytes 549 bytes 406 bytes The pub and priv COSE key parameters, and the COSE_Sign1 / JWS signature bytes, MUST use these lengths for the selected algorithm. [RFC Editor Note: Please replace TBD-KTY with the integer assigned by IANA in the COSE Key Types registry, and remove this note.]

SQIsign-Specific Key Parameters The following key-type-specific parameters are defined for kty = SQIsign. As with other key types (e.g., OKP), these labels are scoped to kty = SQIsign and do not collide with parameters of other key types. Key Parameter Label CBOR Type Description pub -1 bstr SQIsign public key priv -2 bstr SQIsign private key The priv parameter MUST NOT appear in a public COSE_Key and MUST be handled as sensitive key material.

COSE Key Format Examples Examples use CBOR diagnostic notation (). TBD-KTY denotes the value to be assigned to the SQIsign key type by IANA. Placeholder key material in this subsection is replaced by the full Version 3.0 L1 count = 0 public and private keys in the JWK examples and in the Test Vectors appendix.

Public Key (COSE_Key) cbor-diag { 1: TBD-KTY, / kty: SQIsign / 3: -61, / alg: SQIsign-L1 / -1: h'[PUBLIC_KEY]' / pub: SQIsign public key bytes / }

Private Key (COSE_Key) cbor-diag { 1: TBD-KTY, / kty: SQIsign / 3: -61, / alg: SQIsign-L1 / -1: h'[PUBLIC_KEY]', / pub: SQIsign public key bytes / -2: h'[PRIVATE_KEY]' / priv: SQIsign private key bytes / }

COSE Signature Format SQIsign signatures in COSE follow the standard COSE_Sign1 structure : COSE_Sign1 = [ protected: bstr .cbor header_map, unprotected: header_map, payload: bstr / nil, signature: bstr ] The signature field contains the raw SQIsign signature bytes.

Protected Headers The protected header MUST include: cbor-diag { 1: -61 / alg: SQIsign-L1, -62 for L3, -63 for L5 / }

Example COSE_Sign1 Structure cbor-diag 18( / COSE_Sign1 tag / [ h'A101383C', / protected: {"alg": -61} / {}, / unprotected / h'546869732069732074686520636F6E74656E742E', / payload / h'[SQISIGN_SIGNATURE_BYTES]' / signature / ] )

JOSE Integration

JSON Web Signature (JWS) Algorithm Registration The following algorithm identifiers are registered for use in the JWS "alg" header parameter for JSON Web Signatures : Algorithm Name Description Implementation Requirements SQIsign-L1 SQIsign NIST Level I Optional SQIsign-L3 SQIsign NIST Level III Optional SQIsign-L5 SQIsign NIST Level V Optional

JSON Web Key (JWK) Representation SQIsign keys are represented in JWK format as follows:

Public Key Parameters Parameter Type Description kty string Key type: "SQIsign" alg string Algorithm: "SQIsign-L1", "SQIsign-L3", or "SQIsign-L5" pub string Base64url-encoded public key kid string Key ID (optional) use string Public key use: "sig" (optional) key_ops array Key operations: [verify] (optional)

Private Key Parameters Private keys include all public key parameters plus: Parameter Type Description priv string Base64url-encoded private key

JWK Examples

Public Key (JWK) Example json { "kty": "SQIsign", "alg": "SQIsign-L1", "pub": "qpQ1lOt9y17uvjDR0maUGxEMA0gEqVihUfMI6KPf4FtP7fjRL6JdohXKLqXn40aBCjDSPmLAFTba2ZAZAdHHKoHpEkNsuVwO2SEwCp8QFzCbKQU", "kid": "2027-01-device-key", "use": "sig", "key_ops": ["verify"] } These pub / priv values are the NIST KAT count = 0 SQIsign-L1 public and private keys (83 and 270 bytes). They are written on one line so the HTML rendering does not split the base64url with backslash continuations.

Private Key (JWK) Example json { "kty": "SQIsign", "alg": "SQIsign-L1", "pub": "qpQ1lOt9y17uvjDR0maUGxEMA0gEqVihUfMI6KPf4FtP7fjRL6JdohXKLqXn40aBCjDSPmLAFTba2ZAZAdHHKoHpEkNsuVwO2SEwCp8QFzCbKQU", "priv": "qpQ1lOt9y17uvjDR0maUGxEMA0gEqVihUfMI6KPf4FtP7fjRL6JdohXKLqXn40aBCjDSPmLAFTba2ZAZAdHHKoHpEkNsuVwO2SEwCp8QFzCbKQW_CKV0iLE4Zl2HIxtASCjJFQIaHnMBAAAAAAAAAAAAAAAAAAAAAAAAAL2Qzj9nqvCrp1eY7Oz4Hh3Eki8FJAEAAAAAAAAAAAAAAAAAAAAAAAAAdAgfTqWL5O7_a9WWvTse5i697vhgAAAAAAAAAAAAAAAAAAAAAAAAAADwFeh0ATALbSYxQtfN7OxlczkvA59kFGY0vn5GXMmhJjUDf8VF4ujDkQJ-DIyaTKO4R13AO5ZwR0VTX-iuQbyP", "kid": "2027-01-device-key", "use": "sig", "key_ops": ["sign"] }

JWS Compact Serialization A JWS using SQIsign follows the standard compact serialization: BASE64URL(UTF8(JWS Protected Header)) || '.' || BASE64URL(JWS Payload) || '.' || BASE64URL(JWS Signature)

Example JWS Protected Header json { "alg": "SQIsign-L1", "typ": "JWT" } Base64url-encoded: eyJhbGciOiJTUUlzaWduLUwxIiwidHlwIjoiSldUIn0

Complete JWS Example eyJhbGciOiJTUUlzaWduLUwxIiwidHlwIjoiSldUIn0 . [BASE64URL_PAYLOAD] . [BASE64URL_SQISIGN_SIGNATURE]

Implementation Considerations

Signature and Key Generation Implementations MUST follow the SQIsign specification for: Key pair generation Signature generation Signature verification

Randomness Requirements SQIsign signature generation requires high-quality randomness. Implementations MUST use a cryptographically secure random number generator (CSRNG) compliant with or equivalent.

Side-Channel Protections Implementations SHOULD implement protections against: Timing attacks Power analysis Fault injection attacks Particularly for constrained devices deployed in physically accessible environments.

Performance Trade-offs Implementers should be aware: Signing is computationally expensive: Consider pre-signing or batch operations Verification is moderate: Suitable for resource-constrained verifiers Size is exceptional: Minimizes bandwidth and storage

Interoperability Testing Early implementations SHOULD participate in interoperability testing to ensure: Consistent signature generation and verification Proper encoding in COSE and JOSE formats Cross-platform compatibility

Performance testing under real-world scenarios public metrics, interoperability and performance testing of the proposed WASM versions can be evaluated on a live testbed .

Security Considerations

Algorithm Security The security of SQIsign relies primarily on the hardness of finding isogenies between supersingular elliptic curves. These assumptions are different from lattice-based schemes, providing cryptographic diversity in the post-quantum landscape.

Quantum Security SQIsign is designed to resist attacks by large-scale quantum computers. The three parameter sets provide security equivalent to AES-128, AES-192, and AES-256 against both classical and quantum adversaries.

Cryptanalysis and Algorithm Maturity As of this writing, SQIsign is undergoing active cryptanalytic review: NIST Round 3 evaluation: Academic research: Ongoing analysis of isogeny-based cryptography Known attacks: No attacks are currently known that recover private keys for the standardized parameter sets within their claimed security levels. However, the scheme and its underlying assumptions remain under active study. Implementers are advised: - Monitor NIST announcements and updates - Follow academic literature on isogeny cryptanalysis - Be prepared to deprecate or update as cryptanalysis evolves

Implementation Security

Random Number Generation Poor randomness can completely compromise SQIsign security. Implementations MUST use robust CSRNGs, especially on constrained devices with limited entropy sources.

Side-Channel Resistance Constrained devices may be physically accessible to attackers. Implementations SHOULD: Use constant-time algorithms where possible Implement countermeasures against DPA/SPA Consider fault attack mitigations

Key Management Private keys MUST be protected with appropriate access controls Consider hardware security modules (HSMs) or secure elements for key storage Implement key rotation policies appropriate to the deployment

Cryptographic Agility Organizations deploying SQIsign SHOULD: Maintain hybrid deployments with classical algorithms during transition Plan for algorithm migration if cryptanalysis reveals weaknesses Monitor NIST and IRTF guidance on PQC deployment

Constrained Device Specific Risks IoT devices face unique challenges: Physical access: Devices may be deployed in hostile environments Limited update capability: Firmware updates may be infrequent or impossible Long deployment lifetimes: Devices may operate for 10+ years Design systems with: - Defense in depth (multiple security layers) - Remote update capability when possible - Graceful degradation if algorithm is compromised

IANA Considerations

Additions to Existing Registries IANA is requested to add the following entries to the COSE and JOSE registries. The following completed registration actions are provided as described in and .

New COSE Algorithms IANA is requested to register the following entries in the "COSE Algorithms" registry: Name Value Description Capabilities Change Cont Ref Rec'd SQIsign-L1 -61 SQIsign NIST L I kty IETF THIS-RFC No SQIsign-L3 -62 SQIsign NIST L III kty IETF THIS-RFC No SQIsign-L5 -63 SQIsign NIST L V kty IETF THIS-RFC No

New COSE Key Types IANA is requested to register the following entry in the "COSE Key Types" registry: Name Value Description Capabilities Change Cont Ref SQIsign TBD-KTY SQIsign pub key sign, verify IETF THIS-RFC [RFC Editor Note: Please replace TBD-KTY with the next available positive integer assigned by IANA in the COSE Key Types registry.]

New COSE Key Type Parameters IANA is requested to register the following entries in the "COSE Key Type Parameters" registry: Key Type Name Label CBOR Type Desc Change Cont Reference TBD-KTY pub -1 bstr SQIsign Public key IETF THIS-RFC TBD-KTY priv -2 bstr SQIsign Private key IETF THIS-RFC [RFC Editor Note: Please replace TBD-KTY with the numeric value assigned in the COSE Key Types registry above.]

New JWS Algorithms IANA is requested to register the following entries in the "JSON Web Signature and Encryption Algorithms" registry: Algorithm Name Desc Impl Req Change Cont Ref Recommended SQIsign-L1 SQIsign NIST L I Optional IETF THIS-RFC No SQIsign-L3 SQIsign NIST L III Optional IETF THIS-RFC No SQIsign-L5 SQIsign NIST L V Optional IETF THIS-RFC No

New JSON Web Key Types IANA is requested to register the following entry in the "JSON Web Key Types" registry: "kty" Param Value Key Type Desc Change Cont Reference SQIsign SQIsign public key IETF THIS-RFC

New JSON Web Key Parameters IANA is requested to register the following entries in the "JSON Web Key Parameters" registry: Param Name Desc Used with "kty" Val Change Cont Reference pub Public key SQIsign IETF THIS-RFC priv Private key SQIsign IETF THIS-RFC

Acknowledgments The authors would like to thank: Luca De Feo for reviewing draft-00 and providing valuable feedback. Any remaining errors are solely the responsibility of the authors. The SQIsign design team for groundbreaking work on isogeny-based signatures. The W3C Verifiable Credentials and WebAuthn Working Groups, whose specifications this document builds on. The NIST PQC team for managing the standardization process. The COSE and JOSE working groups for guidance on integration. The IRTF Crypto Forum Research Group for ongoing cryptanalytic review. Aerospace and constrained-telemetry engineers/contractors who suggested the idea for and in later versions , together a public testbed for testing, evaluating, and critiquing working WASM and WebGPU-accelerated implementations of all three SQIsign security levels. Early implementers, those who found bugs in our code and kindly pointed us to them, and others who provided valuable feedback. This work builds upon the template established by and similar PQC integration efforts.

References This document has a normative reference to and , both currently at Informational status, which is a lower maturity level than required for normative references from a Standards Track document. This is a conscious choice by the authors; see and for background on this practice.

Normative References Populated automatically from metadata

Informative References Populated automatically from metadata

JSON Web Signature (JWS) represents content secured with digital signatures or Message Authentication Codes (MACs) using JSON-based data structures. Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) specification and an IANA registry defined by that specification. Related encryption capabilities are described in the separate JSON Web Encryption (JWE) specification. A JSON Web Key (JWK) is a JavaScript Object Notation (JSON) data structure that represents a cryptographic key. This specification also defines a JWK Set JSON data structure that represents a set of JWKs. Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) specification and IANA registries established by that specification. Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. There is a need to be able to define basic security services for this data format. This document defines the CBOR Object Signing and Encryption (COSE) protocol. This specification describes how to create and process signatures, message authentication codes, and encryption using CBOR for serialization. This specification additionally describes how to represent cryptographic keys using CBOR. This document, along with RFC 9053, obsoletes RFC 8152. Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. There is a need to be able to define basic security services for this data format. This document defines a set of algorithms that can be used with the CBOR Object Signing and Encryption (COSE) protocol (RFC 9052). This document, along with RFC 9052, obsoletes RFC 8152. The CBOR Object Signing and Encryption (COSE) syntax (see RFC 9052) does not define any direct methods for using hash algorithms. There are, however, circumstances where hash algorithms are used, such as indirect signatures, where the hash of one or more contents are signed, and identification of an X.509 certificate or other object by the use of a fingerprint. This document defines hash algorithms that are identified by COSE algorithm identifiers. In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. Security systems are built on strong cryptographic algorithms that foil pattern analysis attempts. However, the security of these systems is dependent on generating secret quantities for passwords, cryptographic keys, and similar quantities. The use of pseudo-random processes to generate secret quantities can result in pseudo-security. A sophisticated attacker may find it easier to reproduce the environment that produced the secret quantities and to search the resulting small set of possibilities than to locate the quantities in the whole of the potential number space. Choosing random quantities to foil a resourceful and motivated adversary is surprisingly difficult. This document points out many pitfalls in using poor entropy sources or traditional pseudo-random number generation techniques for generating such quantities. It recommends the use of truly random hardware techniques and shows that the existing hardware on many systems can be used for this purpose. It provides suggestions to ameliorate the problem when a hardware solution is not available, and it gives examples of how large such quantities need to be for some applications. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. The Concise Binary Object Representation (CBOR) is a data format whose design goals include the possibility of extremely small code size, fairly small message size, and extensibility without the need for version negotiation. These design goals make it different from earlier binary serializations such as ASN.1 and MessagePack. This document obsoletes RFC 7049, providing editorial improvements, new details, and errata fixes while keeping full compatibility with the interchange format of RFC 7049. It does not create a new version of the format. IETF procedures generally require that a standards track RFC may not have a normative reference to another standards track document at a lower maturity level or to a non standards track specification (other than specifications from other standards bodies). For example, a standards track document may not have a normative reference to an informational RFC. Exceptions to this rule are sometimes needed as the IETF uses informational RFCs to describe non-IETF standards or IETF-specific modes of use of such standards. This document clarifies and updates the procedure used in these circumstances. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. The Internet Engineering Task Force (IETF) and Request for Comments (RFC) Editor have a long-standing rule that a document at a given maturity level cannot be published until all of the documents that it references as normative are at that maturity level or higher. This rule has sometimes resulted in very long publication delays for documents and some claims that it was a major obstruction to advancing documents in maturity level. The IETF agreed on a way to bypass this rule with RFC 3967. This document describes a simpler procedure for downward references to Standards-Track and Best Current Practice (BCP) documents, namely "note and move on". The procedure in RFC 3967 still applies for downward references to other classes of documents. In both cases, annotations should be added to such References. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. mesur.io Tradeverifyd University of the Bundeswehr Munich This document specifies JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE) serializations for FFT (fast-Fourier transform) over NTRU-Lattice-Based Digital Signature Algorithm (FN-DSA), a Post-Quantum Cryptography (PQC) digital signature scheme defined in US NIST FIPS 206 (expected to be published in late 2026 early 2027). It does not define new cryptographic primitives; rather, it specifies how existing FN-DSA mechanisms are serialized for use in JOSE and COSE. This document registers signature algorithms for JOSE and COSE, specifically FN-DSA-512 and FN-DSA-1024. Tradeverifyd Tradeverifyd This document specifies JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE) serializations for Module- Lattice-Based Digital Signature Standard (ML-DSA), a Post-Quantum Cryptography (PQC) digital signature scheme defined in US NIST FIPS 204. NIST SQIsign team IACR ePrint Archive Fido Alliance National Security Agency RustyKey® RustyKey® Measured on MacBook Pro, Apple M4 Max, 128GB RAM, macOS 26.6.2, Chrome 152.0.7977.65 (arm64) University of Quantum Science ISO U.S. Department of Transportation European Commission, Directorate-General for Internal Market, Industry Agence nationale de la sécurité des systèmes d'information US Executive Office of the President United Arab Emirates Government, Cyber Security Council Cyber Security Agency of Singapore (CSA)

Test Vectors Vectors use NIST KAT count = 0 from upstream SQIsign Version 3.0 response files (PQCsignKAT_270_SQIsign_p324_3.rsp, PQCsignKAT_417_SQIsign_p500_27.rsp, PQCsignKAT_549_SQIsign_p664_17.rsp). Count = 0 uses the same 33-byte message at each security level (mlen = 33, hex below) so implementers can compare keys and signatures. Algorithm identifiers -61, -62, and -63 map to SQIsign-L1, SQIsign-L3, and SQIsign-L5 respectively. The detached signature is the first CRYPTO_BYTES of sm; the message is the remainder.

SQIsign-L1 Test Vectors

Example 1: Simple Message Signing The following test vector is NIST KAT count = 0 for SQIsign-L1 (p324_3): 83-byte public key, 200-byte signature. Message (hex): d81c4d8d734fcbfbeade3d3f8a039faa2a2c9957e835ad55b2 \ 2e75bf57bb556ac8 Public Key (hex): aa943594eb7dcb5eeebe30d1d266941b110c034804a958a1 \ 51f308e8a3dfe05b4fedf8d12fa25da215ca2ea5e7e346810a30d23e62c01536da \ d9901901d1c72a81e912436cb95c0ed921300a9f1017309b2905 Public Key (Base64url): qpQ1lOt9y17uvjDR0maUGxEMA0gEqVihUfMI6KPf4F \ tP7fjRL6JdohXKLqXn40aBCjDSPmLAFTba2ZAZAdHHKoHpEkNsuVwO2SEwCp8QFzCb \ KQU Signature (hex): af9119c1d62766fe4fc73791f2dfe76016e57eed4fc02d9e \ 1a34244262cff1a352bfe6d09a98eedb2e0c04e419b973696f5c9f12135565ee41 \ 0b05cb9b9db2655218ca918d151da2b36d5a14510d9f6cc729d1ebcf6d05702826 \ d5a7013998e33a1750117e4d665ffdd21ed048147a2f5f7955d463af8cb53a673f \ 66ae0dd5380f186302369a07d48ffde881f955a871ddc372acd4a6401884530b68 \ 35fd5a050eea188026474533afa387c4cc966cef0d81ec694f3c90e2cee6c6c0cb \ 0ebf82682562d6d7d80d02 Signature (Base64url): r5EZwdYnZv5PxzeR8t_nYBblfu1PwC2eGjQkQmLP8a \ NSv-bQmpju2y4MBOQZuXNpb1yfEhNVZe5BCwXLm52yZVIYypGNFR2is21aFFENn2zH \ KdHrz20FcCgm1acBOZjjOhdQEX5NZl_90h7QSBR6L195VdRjr4y1Omc_Zq4N1TgPGG \ MCNpoH1I_96IH5Vahx3cNyrNSmQBiEUwtoNf1aBQ7qGIAmR0Uzr6OHxMyWbO8Ngexp \ TzyQ4s7mxsDLDr-CaCVi1tfYDQI

COSE_Sign1 Complete Example cbor-diag 18( [ h'a101383c', / protected: {"alg": -61} / {}, / unprotected / h'd81c4d8d734fcbfbeade3d3f8a039faa2a2c9957e835ad55b22e75bf57bb \ 556ac8', / payload / h'af9119c1d62766fe4fc73791f2dfe76016e57eed4fc02d9e1a34244262cf \ f1a352bfe6d09a98eedb2e0c04e419b973696f5c9f12135565ee410b05cb9b \ 9db2655218ca918d151da2b36d5a14510d9f6cc729d1ebcf6d05702826d5a7 \ 013998e33a1750117e4d665ffdd21ed048147a2f5f7955d463af8cb53a673f \ 66ae0dd5380f186302369a07d48ffde881f955a871ddc372acd4a640188453 \ 0b6835fd5a050eea188026474533afa387c4cc966cef0d81ec694f3c90e2ce \ e6c6c0cb0ebf82682562d6d7d80d02' ] )

JWS Complete Example eyJhbGciOiJTUUlzaWduLUwxIiwidHlwIjoiSldUIn0 . 2BxNjXNPy_vq3j0_igOfqiosmVfoNa1Vsi51v1e7VWrI . r5EZwdYnZv5PxzeR8t_nYBblfu1PwC2eGjQkQmLP8aNSv-bQmpju2y4MBOQZuXNpb1 \ yfEhNVZe5BCwXLm52yZVIYypGNFR2is21aFFENn2zHKdHrz20FcCgm1acBOZjjOhdQ \ EX5NZl_90h7QSBR6L195VdRjr4y1Omc_Zq4N1TgPGGMCNpoH1I_96IH5Vahx3cNyrN \ SmQBiEUwtoNf1aBQ7qGIAmR0Uzr6OHxMyWbO8NgexpTzyQ4s7mxsDLDr-CaCVi1tfY \ DQI

SQIsign-L3 Test Vectors

Example 1: Simple Message Signing The following test vector is NIST KAT count = 0 for SQIsign-L3 (p500_27): 129-byte public key, 306-byte signature. Message (hex): d81c4d8d734fcbfbeade3d3f8a039faa2a2c9957e835ad55b2 \ 2e75bf57bb556ac8 Public Key (hex): 120516638bdb039f8ef434d76d76eef56f2c037b50f7adee \ 93406dbddf66522741d1b2c6c5fc1d9c5716d958b6fa65fbdb954dad121a74621e \ 8e6b38fb6f5a01ad41cecf084bc914e4cd93d3e2be6a2445f13d6c7d0bd3595c30 \ d4f6c607b90d3cabae3528656570d1fbee620c2bd02fe1f7d919ddad183f6bdb14 \ 981d06910113 Public Key (Base64url): EgUWY4vbA5-O9DTXbXbu9W8sA3tQ963uk0Btvd9mUi \ dB0bLGxfwdnFcW2Vi2-mX725VNrRIadGIejms4-29aAa1Bzs8IS8kU5M2T0-K-aiRF \ 8T1sfQvTWVww1PbGB7kNPKuuNShlZXDR--5iDCvQL-H32RndrRg_a9sUmB0GkQET Signature (hex): 0dd29c66b2d5c521cf9b77e84986c1cbd7ba2a9db1cb4dc2 \ c3c95ea86960d8f3e9013c86a39af926db126df33a32f41b239d091d54475263a5 \ dccb06d29c980014ef29bd87c65f1d0f52ab25227c1b87c7d2499cde2b4831b425 \ 55cedfb4ad3fd3f4d366e83407a93603617843a545805f6323bb0f4d7779849b62 \ 1e2460850137910e07515f966e11a5a6a8267dff3d30b696286812353c706a1b7f \ 302d86846591eb5a4f51308f1960fcb0c33a35a1616c2594b3637eb499ec924493 \ be9c580bb75e159eb8f293a08bc38373c110e6cb6aa1e5b17c4a5b6b0792fe31a1 \ 788b4e535f8aa82c90f684b93c64faa671bd5ba50b50405c91568cdcd818afd444 \ 4cc7a34821d485cf67d4d72ef2b9786d8dce77b598acec2b61c504203156e08436 \ 4626a1ac1cc478f79d0ef6e27e7cdcff0a09 Signature (Base64url): DdKcZrLVxSHPm3foSYbBy9e6Kp2xy03Cw8leqGlg2P \ PpATyGo5r5JtsSbfM6MvQbI50JHVRHUmOl3MsG0pyYABTvKb2Hxl8dD1KrJSJ8G4fH \ 0kmc3itIMbQlVc7ftK0_0_TTZug0B6k2A2F4Q6VFgF9jI7sPTXd5hJtiHiRghQE3kQ \ 4HUV-WbhGlpqgmff89MLaWKGgSNTxwaht_MC2GhGWR61pPUTCPGWD8sMM6NaFhbCWU \ s2N-tJnskkSTvpxYC7deFZ648pOgi8ODc8EQ5stqoeWxfEpbaweS_jGheItOU1-KqC \ yQ9oS5PGT6pnG9W6ULUEBckVaM3NgYr9RETMejSCHUhc9n1Ncu8rl4bY3Od7WYrOwr \ YcUEIDFW4IQ2RiahrBzEePedDvbifnzc_woJ

COSE_Sign1 Complete Example cbor-diag 18( [ h'a101383d', / protected: {"alg": -62} / {}, / unprotected / h'd81c4d8d734fcbfbeade3d3f8a039faa2a2c995 \ 7e835ad55b22e75bf57bb556ac8', / payload / h'0dd29c66b2d5c521cf9b77e84986c1cbd7ba2a9 \ db1cb4dc2c3c95ea86960d8f3e9013c86a39af926db126df33a32f41b239d091 \ d54475263a5dccb06d29c980014ef29bd87c65f1d0f52ab25227c1b87c7d2499 \ cde2b4831b42555cedfb4ad3fd3f4d366e83407a93603617843a545805f6323b \ b0f4d7779849b621e2460850137910e07515f966e11a5a6a8267dff3d30b6962 \ 86812353c706a1b7f302d86846591eb5a4f51308f1960fcb0c33a35a1616c259 \ 4b3637eb499ec924493be9c580bb75e159eb8f293a08bc38373c110e6cb6aa1e \ 5b17c4a5b6b0792fe31a1788b4e535f8aa82c90f684b93c64faa671bd5ba50b5 \ 0405c91568cdcd818afd4444cc7a34821d485cf67d4d72ef2b9786d8dce77b59 \ 8acec2b61c504203156e084364626a1ac1cc478f79d0ef6e27e7cdcff0a09' / signature / ] )

JWS Complete Example eyJhbGciOiJTUUlzaWduLUwzIiwidHlwIjoiSldUIn0 . 2BxNjXNPy_vq3j0_igOfqiosmVfoNa1Vsi51v1e7VWrI . DdKcZrLVxSHPm3foSYbBy9e6Kp2xy03Cw8leqGlg2PPpATyGo5r5JtsSbfM6MvQbI50JHVRH \ UmOl3MsG0pyYABTvKb2Hxl8dD1KrJSJ8G4fH0kmc3itIMbQlVc7ftK0_0_TTZug0B6k2A2F4 \ Q6VFgF9jI7sPTXd5hJtiHiRghQE3kQ4HUV-WbhGlpqgmff89MLaWKGgSNTxwaht_MC2GhGWR \ 61pPUTCPGWD8sMM6NaFhbCWUs2N-tJnskkSTvpxYC7deFZ648pOgi8ODc8EQ5stqoeWxfEpba \ weS_jGheItOU1-KqCyQ9oS5PGT6pnG9W6ULUEBckVaM3NgYr9RETMejSCHUhc9n1Ncu8rl4b \ Y3Od7WYrOwrYcUEIDFW4IQ2RiahrBzEePedDvbifnzc_woJ

SQIsign-L5 Test Vectors

Example 1: Simple Message Signing The following test vector is NIST KAT count = 0 for SQIsign-L5 (p664_17): 169-byte public key, 406-byte signature. Message (hex): d81c4d8d734fcbfbeade3d3f8a039faa2a2c9957e835ad55b2 \ 2e75bf57bb556ac8 Public Key (hex): 549bb0a2966d55e5941b657e68f19f568e410cc9eb7a3d40 \ 4b0c14a9fb232c53258d19e6b62d609dab0562115954074551bce47a2d155d7336 \ 2805100db9f0c09b98390ca19e65068a0a162efa919b3ac00769075a4f55f8c80c \ b15b8111727cc0c522bb3fba1f8fefe573060623999270501c9f10bda692de97e4 \ 578deb50f7da513e3214112f47e6d198dd4274c4468934df5de2774b1c98a8fe1d \ 1c030b8797568b209965b11008 Public Key (Base64url): VJuwopZtVeWUG2V-aPGfVo5BDMnrej1ASwwUqfsjLF \ MljRnmti1gnasFYhFZVAdFUbzkei0VXXM2KAUQDbnwwJuYOQyhnmUGigoWLvqRmzrA \ B2kHWk9V-MgMsVuBEXJ8wMUiuz-6H4_v5XMGBiOZknBQHJ8QvaaS3pfkV43rUPfaUT \ 4yFBEvR-bRmN1CdMRGiTTfXeJ3SxyYqP4dHAMLh5dWiyCZZbEQCA Signature (hex): 8c18127b477ffd59bea23a07a4d02a4d6c9086111d98f1c5 \ dc50f3e4bdcec99e58203f23ba228536158843171e10b7be4f822ef0fdcd2690f3 \ 0b75906c798921fa2fda66c958279a3dc11e21bbf5e46885710b06621f6e89e7df \ 3b12ec4b01d61f91e84b30398f48fd6aeae35c66d5b866c58d74a635298d84d827 \ 36c52390375d5eb3b9e474015a5a68af3a941e7b2c2ba475d7a9c779cf7f726f4b \ 8d13972b28e093d4ff568310f537975ebc41683b45b1213ba8f75619507422077a \ ba77d2ba8535f91dec6e94619ab005855923a7ed98a193354499831ad90141fa3e \ 2307401a680e49198aa71ddb22a7a9b105b3f74dfebdab6231df2b3df40de17da5 \ 7c08b9290c9f766c029c81b7680e026a60b558ebda84b289c4068031aaf840c1de \ 3ea212177ed309c8f719d2383230f14654cd64d1f0ec0ebaef2c13afed1c024602 \ 05c212a2849877f8cf34134b7f95620b5b3137ce3afe8f71e6d965c8cedd7d0a38 \ 510f098d07a6a8eeec98ca65862eee6c4902eda308a9a18db4d16e0869ad9c8648 \ eb79e64952f77d07161092696e49d214710225 Signature (Base64url): jBgSe0d__Vm-ojoHpNAqTWyQhhEdmPHF3FDz5L3OyZ \ 5YID8juiKFNhWIQxceELe-T4Iu8P3NJpDzC3WQbHmJIfov2mbJWCeaPcEeIbv15GiF \ cQsGYh9uieffOxLsSwHWH5HoSzA5j0j9aurjXGbVuGbFjXSmNSmNhNgnNsUjkDddXr \ O55HQBWlporzqUHnssK6R116nHec9_cm9LjROXKyjgk9T_VoMQ9TeXXrxBaDtFsSE7 \ qPdWGVB0Igd6unfSuoU1-R3sbpRhmrAFhVkjp-2YoZM1RJmDGtkBQfo-IwdAGmgOSR \ mKpx3bIqepsQWz903-vatiMd8rPfQN4X2lfAi5KQyfdmwCnIG3aA4CamC1WOvahLKJ \ xAaAMar4QMHePqISF37TCcj3GdI4MjDxRlTNZNHw7A667ywTr-0cAkYCBcISooSYd_ \ jPNBNLf5ViC1sxN846_o9x5tllyM7dfQo4UQ8JjQemqO7smMplhi7ubEkC7aMIqaGN \ tNFuCGmtnIZI63nmSVL3fQcWEJJpbknSFHECJQ

COSE_Sign1 Complete Example cbor-diag 18( [ h'a101383e', / protected: {"alg": -63} / {}, / unprotected / h'd81c4d8d734fcbfbeade3d3f8a039faa2a2c995 \ 7e835ad55b22e75bf57bb556ac8', / payload / h'8c18127b477ffd59bea23a07a4d02a4d6c90861 \ 11d98f1c5dc50f3e4bdcec99e58203f23ba228536158843171e10b7be4f822ef \ 0fdcd2690f30b75906c798921fa2fda66c958279a3dc11e21bbf5e46885710b0 \ 6621f6e89e7df3b12ec4b01d61f91e84b30398f48fd6aeae35c66d5b866c58d7 \ 4a635298d84d82736c52390375d5eb3b9e474015a5a68af3a941e7b2c2ba475d \ 7a9c779cf7f726f4b8d13972b28e093d4ff568310f537975ebc41683b45b1213 \ ba8f75619507422077aba77d2ba8535f91dec6e94619ab005855923a7ed98a19 \ 3354499831ad90141fa3e2307401a680e49198aa71ddb22a7a9b105b3f74dfeb \ dab6231df2b3df40de17da57c08b9290c9f766c029c81b7680e026a60b558ebd \ a84b289c4068031aaf840c1de3ea212177ed309c8f719d2383230f14654cd64d \ 1f0ec0ebaef2c13afed1c02460205c212a2849877f8cf34134b7f95620b5b313 \ 7ce3afe8f71e6d965c8cedd7d0a38510f098d07a6a8eeec98ca65862eee6c490 \ 2eda308a9a18db4d16e0869ad9c8648eb79e64952f77d07161092696e49d2147 \ 10225' / signature / ] )

JWS Complete Example eyJhbGciOiJTUUlzaWduLUw1IiwidHlwIjoiSldUIn0 . 2BxNjXNPy_vq3j0_igOfqiosmVfoNa1Vsi51v1e7VWrI . jBgSe0d__Vm-ojoHpNAqTWyQhhEdmPHF3FDz5L3OyZ5YID8juiKFNhWIQxceELe-T4Iu8P3N \ JpDzC3WQbHmJIfov2mbJWCeaPcEeIbv15GiFcQsGYh9uieffOxLsSwHWH5HoSzA5j0j9aurj \ XGbVuGbFjXSmNSmNhNgnNsUjkDddXrO55HQBWlporzqUHnssK6R116nHec9_cm9LjROXKyjg \ k9T_VoMQ9TeXXrxBaDtFsSE7qPdWGVB0Igd6unfSuoU1-R3sbpRhmrAFhVkjp-2YoZM1RJmD \ GtkBQfo-IwdAGmgOSRmKpx3bIqepsQWz903-vatiMd8rPfQN4X2lfAi5KQyfdmwCnIG3aA4C \ amC1WOvahLKJxAaAMar4QMHePqISF37TCcj3GdI4MjDxRlTNZNHw7A667ywTr-0cAkYCBcIS \ ooSYd_jPNBNLf5ViC1sxN846_o9x5tllyM7dfQo4UQ8JjQemqO7smMplhi7ubEkC7aMIqaGN \ tNFuCGmtnIZI63nmSVL3fQcWEJJpbknSFHECJQ

Implementation Status [RFC Editor: Please remove this section before publication] This section records the status of known implementations at the time of writing.

Open Source Implementations

Reference Implementation Organization: SQIsign team Repository: https://github.com/SQISign/the-sqisign Language: C License: Apache-2.0 Status: Active development COSE/JOSE Support: Not yet integrated

Rust Implementation Organization: IETF - Community implementation Repository: IETF Language: Rust License: IETF COSE Support: Planned Status: Development

Commercial Implementations [RFC EDITOR: To be populated as vendors implement]

Interoperability Testing Test Suite Location: IETF Participating Organizations: IETF

Design Rationale

Algorithm Identifier Selection The requested algorithm identifiers (-61, -62, -63) are: In the Standards Action range (-255 to -1) per RFC 9053 Sequential for the three parameter sets Not conflicting with existing registrations (verified against IANA COSE registry) Consistent with the approach used for other PQC algorithms

Key Type Design The SQIsign key type is intentionally simple: Only two parameters (pub, priv) following minimalist design Binary encoding (bstr) for efficiency No algorithm-specific encoding—raw bytes from SQIsign spec This approach: - Minimizes CBOR encoding overhead (critical for constrained devices) - Simplifies implementation - Provides future flexibility for parameter set evolution

Change Log [RFC Editor Note: Please remove this section before publication.]

draft-mott-cose-sqisign-09 aligned public-key, private-key, and signature lengths with SQIsign specification Version 3.0 (2026-09-01) and the nist-v3 reference C fixed HTML/markdown table rendering from "SQIsign Key Parameters" (footnote asterisks were being parsed as list markup) used preferred CBOR encodings for COSE alg values -61 / -62 / -63 replaced COSE/JOSE examples and NIST KAT count = 0 vectors with the larger Version 3.0 keys and signatures noted that KAT count = 0 signs a 33-byte message (mlen = 33) removed leading asterisks from IANA TBD-KTY table cells so HTML rendering does not treat them as list markup

draft-mott-cose-sqisign versions prior to -09 fixed grammar and typos added Section motivating SQIsign adoption via real-world VC selective-disclosure deployments (linkable: hazmat manifest unlinkable: mDL) constrained to consumer-device-readable QR codes, citing testbed comparison against FN-DSA-512 removed "back-of-envelope extrapolations, vaguely sourced statistics, some without an immutable or obvious authoritative citation" added international regulatory context to existing sections citing new country-level policy directives to support claims of cross-jurisdictional urgency and avoid single-country framing added section "SQIsign Variants and the Post-SIKE Landscape" incorporated technical corrections and feedback from Luca De Feo updated the Abstract and Introduction to utilize more neutral, objective language removed vendor-specific branding in favor of generic cryptographic terminology fixed various formatting issues added SQIsign-L3 and SQIsign-L5 COSE_Sign1 and JWS test vectors (algorithms -62 and -63) documented NIST KAT count = 0 byte values for cross-implementation checks added informational resource for interactive working code public testbed updated after SQISign advances to NIST round 3 with 8 other candidates