Internal Security Review

Internal Security Review Report

Date: November 27, 2025 Reviewer: CIPHER (AI Assistant) Scope: SIP Protocol SDK v0.1.0 Status: PASSED (with recommendations)

---

Point-in-time snapshot

This report is a historical snapshot captured against SDK v0.1.0 (November 2025). Metrics such as dependency versions, test counts, and open recommendations reflect that release. Several recommendations below have since been addressed (e.g. memory zeroization is now implemented via secure-memory.ts). For the current SDK (v0.9.0), see the live source and the Audit Preparation and Audit Scope documents.

Executive Summary

The SIP Protocol SDK demonstrates strong security practices across cryptographic implementation, input validation, and error handling. The codebase uses industry-standard audited libraries (@noble/*) and follows best practices for privacy-preserving protocols.

Overall Risk Level: LOW

Category	Status	Findings
Cryptographic Implementation	PASS	Excellent use of @noble/* libraries
Code Security	PASS	Comprehensive validation, no info leakage
Protocol Security	PASS	Well-documented threat model
Integration Security	PASS	Standard wallet adapter patterns
Dependencies	PASS	1 moderate (dev-only)

---

Automated Scanning Results

npm audit

1 vulnerability found
Severity: 1 moderate

- esbuild <=0.24.2 (dev dependency via vitest/vite)
  Issue: Development server request handling
  Impact: NONE (dev-only, not in production bundle)
  Recommendation: Update vitest when esbuild 0.25.0 compatible version available

TypeScript Strict Mode

All packages pass strict type checking:
- @sip-protocol/types: PASS
- @sip-protocol/sdk: PASS
- @sip-protocol/demo: PASS

Secret Detection

No hardcoded secrets found in production code
- zcash/rpc-client.ts:11 - JSDoc example only (acceptable)

Insecure Random Number Generation

Math.random() usage: NONE in production code
- mock-solver.ts:207 - Mock file only (acceptable)
- mock.ts:255,261 - Mock wallet only (acceptable)

All cryptographic operations use @noble/hashes/utils randomBytes (CSPRNG)

---

Cryptographic Implementation Review

Strengths

1. Dependencies: Uses @noble/* libraries (audited, constant-time)

   • @noble/curves v1.3.0 - secp256k1 operations
   • @noble/hashes v1.3.3 - SHA256, HKDF
   • @noble/ciphers v2.2.0 - XChaCha20-Poly1305

2. Random Number Generation: All crypto operations use randomBytes from @noble/hashes

   • stealth.ts:58-59 - Key generation
   • privacy.ts:93,206 - Viewing key and nonces
   • commitment.ts:180 - Blinding factors
   • crypto.ts:66,82 - Intent IDs

3. NUMS Generator Construction: commitment.ts:95-130

   • Uses hash-to-curve with domain separation
   • Verifiable “SIP-PEDERSEN-GENERATOR-H-v1” seed
   • Follows Zcash/Mimblewimble best practices

4. Encryption: privacy.ts uses XChaCha20-Poly1305

   • AEAD (authenticated encryption)
   • 24-byte nonces (nonce-misuse resistant)
   • HKDF key derivation with domain separation

5. Stealth Addresses: EIP-5564 compliant

   • Proper ECDH key exchange
   • View tag optimization for scanning
   • Correct scalar derivation (hash then mod n)

Findings

ID	Severity	Location	Description	Recommendation
CRYPTO-1	INFO	intent.ts:358	Zero nonce placeholder for validity proof	Document as intentional placeholder for mock proofs
CRYPTO-2	INFO	commitment.ts:187-189	Blinding adjusted to 1n if 0	Documented behavior, acceptable

---

Code Security Review

Input Validation

Status: EXCELLENT

• validation.ts provides comprehensive validators
• All public APIs validate inputs before processing
• Chain IDs, privacy levels validated against allowlists
• Hex strings validated with regex + length checks
• Public keys validated (33 bytes, 02/03 prefix)
• Amounts validated as positive bigints
• Scalars validated against curve order

Error Handling

Status: EXCELLENT

• errors.ts provides structured error hierarchy
• Machine-readable error codes (SIP_XXXX)
• No sensitive data in error messages
• Original causes preserved for debugging
• Serialization support (toJSON)

Console Usage

Production code: 0 instances
Mock code: 1 instance (warning message, acceptable)
JSDoc examples: 4 instances (not executed)

Findings

ID	Severity	Location	Description	Recommendation
CODE-1	LOW	Root	ESLint not installed	Install eslint for code quality checks
CODE-2	INFO	threat_model.md:147	Memory zeroization marked TODO	Implement secure memory clearing for sensitive data

---

Protocol Security Review

Documentation

Status: COMPREHENSIVE

• THREAT_MODEL.md - Adversary capabilities, trust assumptions, security boundaries
• CRYPTO_ASSUMPTIONS.md - Hardness assumptions, parameter justification
• SECURITY_PROPERTIES.md - Privacy guarantees
• KNOWN_LIMITATIONS.md - Edge cases and constraints
• AUDIT_CHECKLIST.md - External audit preparation

Threat Model Validation

The documented threat model accurately reflects the implementation:

1. Adversary Model: Correctly assumes computationally bounded adversary
2. Trust Assumptions: @noble/* libraries justified, PRNG trust documented
3. Security Boundaries: Private keys never cross boundary (verified in code)
4. Data Classification: Matches implementation (blinding factors secret, commitments public)

Findings

ID	Severity	Location	Description	Recommendation
PROTO-1	INFO	THREAT_MODEL.md	Solver availability marked “not implemented yet”	Track as known limitation

---

Integration Security Review

Wallet Adapters

Ethereum (adapter.ts)

• Uses EIP-1193 standard
• Proper error code handling (4001, 4902)
• Event listeners bound/unbound correctly
• Address normalization applied

Solana (adapter.ts)

• Standard Solana wallet interface
• Provider injection for testing
• Cluster configuration supported

Network Communication

• NEAR Intents adapter uses OneClickClient
• JWT token authentication supported
• No sensitive data in API requests (privacy preserved)

Storage

localStorage/sessionStorage: NOT USED
IndexedDB: NOT USED
Filesystem: NOT USED

All sensitive data remains in-memory only.

Findings

ID	Severity	Location	Description	Recommendation
INT-1	INFO	ethereum/adapter.ts:315-328	Mock signature fallback when eth_signTransaction unsupported	Document wallet compatibility

---

Test Coverage

Test Suites: 27 passed
Tests: 1,293 passed, 2 skipped
Duration: 19.84s

E2E tests cover:

• Cross-chain swaps (30 tests)
• Error scenarios (31 tests)
• Performance metrics (22 tests)

---

Recommendations Summary

Critical (0)

None

High (0)

None

Medium (1)

1. CODE-2: Implement memory zeroization for sensitive data (blinding factors, private keys)

Low (1)

1. CODE-1: Install ESLint for consistent code quality

Informational (4)

1. CRYPTO-1: Document zero nonce as placeholder
2. CRYPTO-2: Blinding adjustment is documented
3. PROTO-1: Solver availability tracking
4. INT-1: Document wallet compatibility

---

Sign-off

Internal Review Complete: YES Critical Issues Resolved: N/A (none found) Ready for External Audit: YES (with medium recommendation addressed)

---

Appendix: Files Reviewed

Core Cryptography

• packages/sdk/src/stealth.ts
• packages/sdk/src/crypto.ts
• packages/sdk/src/commitment.ts
• packages/sdk/src/privacy.ts

Validation & Errors

• packages/sdk/src/validation.ts
• packages/sdk/src/errors.ts

Wallet Adapters

• packages/sdk/src/wallet/ethereum/adapter.ts
• packages/sdk/src/wallet/solana/adapter.ts

Network Integration

• packages/sdk/src/adapters/near-intents.ts

Security Documentation

• docs/security/THREAT_MODEL.md
• docs/security/CRYPTO_ASSUMPTIONS.md
• docs/security/SECURITY_PROPERTIES.md
• docs/security/KNOWN_LIMITATIONS.md
• docs/security/AUDIT_CHECKLIST.md