Cose Lib Laravel Package

Technical Evaluation

Architecture Fit

• Strong alignment with modern security standards: The package implements RFC 9052 (COSE Structures) and RFC 9053 (COSE Algorithms), making it ideal for applications requiring CBOR-based cryptographic operations (e.g., WebAuthn, FIDO2, digital health certificates).
• Modular design: Supports six COSE tags (Sign1, Sign, Encrypt0, Encrypt, Mac0, Mac), allowing granular adoption based on use case.
• PHP 8.1+ compatibility: Leverages strict types, PHPStan compliance, and comprehensive test coverage, ensuring robustness in modern PHP stacks.
• Interoperability: Works seamlessly with spomky-labs/cbor-php (required for COSE tag support) and integrates with OpenSSL for cryptographic operations.

Integration Feasibility

• Low friction for PHP ecosystems: Composer-based installation with clear dependencies (spomky-labs/cbor-php, brick/math, spomky-labs/pki-framework).
• CBOR/COSE expertise not required: The library abstracts CBOR encoding/decoding and COSE tag handling, reducing implementation complexity.
• Algorithm flexibility: Supports ECDSA, EdDSA, RSA, and HMAC variants, accommodating diverse cryptographic needs (e.g., ES256 for WebAuthn, Ed25519 for IoT).
• Use-case specificity: Pre-optimized for digital health certificates (EU DCC), WebAuthn/FIDO2, and IoT security, but adaptable to custom scenarios.

Technical Risk

Key Questions for TPM

1. Use Case Priority:
   • Is the primary need signing (COSE_Sign1/Sign), encryption (COSE_Encrypt), or MAC (COSE_Mac)?
   • Example: WebAuthn → Focus on COSE_Sign1 + ES256; IoT → Prioritize COSE_Encrypt0 + Ed25519.
2. Key Management:
   • How will key IDs (kid) and public/private keys be stored/retrieved? (e.g., database, AWS KMS, hardware tokens).
   • Does the system require JWK/JWKS support for key interchange?
3. Interoperability:
   • Must the COSE output interoperate with non-PHP systems (e.g., JavaScript, Rust)? If so, validate CBOR encoding against reference implementations.
4. Compliance:
   • Are there regulatory requirements (e.g., FIPS 140-2, HIPAA) that mandate specific algorithms (e.g., Ed25519 over RSA)?
5. Error Handling:
   • How should signature verification failures or malformed COSE messages be surfaced? (e.g., custom exceptions, HTTP 403).
6. Scaling:
   • For high-volume signing/encryption, will asynchronous processing (e.g., queues) be needed to avoid blocking I/O-bound cryptographic ops?
7. Migration Path:
   • If replacing JWS/JWE, what data format conversions (e.g., JSON ↔ CBOR) are required?
   • Are there legacy systems that need to coexist with COSE?

Integration Approach

Stack Fit

Migration Path

1. Pilot Phase:
   • Start with COSE_Sign1 for digital signatures (e.g., API responses, document signing).
   • Replace JWS with COSE_Sign1 in a non-critical endpoint to validate performance.
2. Incremental Adoption:
   • Phase 1: Signatures → Migrate authentication tokens or audit logs to COSE.
   • Phase 2: Encryption → Secure PII or IoT messages with COSE_Encrypt0.
   • Phase 3: MAC → Add data integrity checks for internal APIs.
3. Dependency Updates:
   • Ensure spomky-labs/cbor-php and brick/math are pinned to stable versions in composer.json.
   • Monitor for breaking changes in PHP 8.2+ (e.g., cryptography extensions).
4. Tooling:
   • Use PHPStan to enforce type safety in COSE operations.
   • Integrate Pest/PhpUnit tests for signature verification and encryption/decryption cycles.

Compatibility

• CBOR/COSE Standards: Fully compliant with RFC 9052/9053; no vendor lock-in.
• Algorithm Overlap:
  • ES256 (COSE) ↔ RS256 (JWT): Can coexist if both are supported.
  • Ed25519 (COSE) ↔ EdDSA (WebAuthn): Native compatibility.
• Key Formats:
  • Supports raw keys, PEM, and JWK (via spomky-labs/pki-framework).
  • No PKCS#12 support; use OpenSSL for conversion if needed.

Sequencing

1. Setup:
   • Install dependencies:

     composer require web-auth/cose-lib spomky-labs/cbor-php
     

   • Configure autoloading in composer.json:

     "autoload": {
       "psr-4": {
         "App\\": "src/",
         "Cose\\": "vendor/web-auth/cose-lib/src"
       }
     }
     

2. Key Infrastructure:
   • Implement key storage (e.g., database table for kid ↔ key pairs).
   • Example:

     // Pseudocode for key retrieval
     $publicKey = KeyRepository::getByKid($coseSign1->getUnprotectedHeader()->get('kid'));
     

3. Core Integration:
   • Signing:

     $coseSign1 = CoseSign1Tag::create(
         $protectedHeader,
         $unprotectedHeader,
         ByteStringObject::create($payload),
         ByteStringObject::create($signature)
     );
     

   • Verification:

     $isValid = openssl_verify(
         (string) Signature1::create($protectedHeader, $payload),
         $derSignature,
         $publicKey,
         'sha256'
     );
     

4. Edge Cases:
   • Handle malformed COSE messages with try-catch:

     try {
         $coseSign1 = $decoder->decode($stream);
     } catch (CborException $e) {
         logError("Invalid COSE message");
         return false;
     }
     

5. Monitoring:
   • Log signature failures and algorithm usage for auditing.