p256k1/TEST_SUITE_SUMMARY.md

Comprehensive Test Suite for secp256k1 Go Implementation

Overview

I have created a comprehensive test suite for the Go implementation of secp256k1 based on the C reference implementation. The test suite includes:

Test Files Created

1. field_test.go - Field Arithmetic Tests

• TestFieldElementBasics: Basic field element operations (zero, one, normalization, equality)
• TestFieldElementSetB32: Setting field elements from 32-byte arrays with various test cases
• TestFieldElementArithmetic: Addition and negation operations
• TestFieldElementMultiplication: Multiplication by small integers
• TestFieldElementNormalization: Weak and full normalization
• TestFieldElementOddness: Even/odd detection
• TestFieldElementConditionalMove: Constant-time conditional assignment
• TestFieldElementStorage: Storage format conversion
• TestFieldElementRandomOperations: Property testing with random values
• TestFieldElementEdgeCases: Boundary conditions and field modulus behavior
• TestFieldElementClear: Secure clearing of sensitive data
• Benchmarks: Performance tests for critical operations

2. scalar_test.go - Scalar Arithmetic Tests

• TestScalarBasics: Basic scalar operations (zero, one, equality)
• TestScalarSetB32: Setting scalars from 32-byte arrays with overflow detection
• TestScalarSetB32Seckey: Secret key validation
• TestScalarArithmetic: Addition, multiplication, and negation
• TestScalarInverse: Modular inverse computation
• TestScalarHalf: Halving operation (division by 2)
• TestScalarProperties: Even/odd and high/low detection
• TestScalarConditionalNegate: Conditional negation
• TestScalarGetBits: Bit extraction for windowing
• TestScalarConditionalMove: Constant-time conditional assignment
• TestScalarRandomOperations: Property testing with random values
• TestScalarEdgeCases: Group order boundary conditions
• Benchmarks: Performance tests for scalar operations

3. group_test.go - Elliptic Curve Group Tests

• TestGroupElementBasics: Infinity point and generator validation
• TestGroupElementNegation: Point negation (affine coordinates)
• TestGroupElementSetXY: Setting points from coordinates
• TestGroupElementSetXOVar: Point decompression from X coordinate
• TestGroupElementEquality: Point comparison
• TestGroupElementJacobianBasics: Jacobian coordinate operations
• TestGroupElementJacobianDoubling: Point doubling in Jacobian coordinates
• TestGroupElementJacobianAddition: Point addition (Jacobian + Jacobian)
• TestGroupElementAddGE: Mixed addition (Jacobian + Affine)
• TestGroupElementStorage: Storage format conversion
• TestGroupElementBytes: Byte array conversion
• TestGroupElementRandomOperations: Associativity and commutativity tests
• TestGroupElementEdgeCases: Infinity handling
• TestGroupElementMultipleDoubling: Powers of 2 multiplication
• Benchmarks: Performance tests for group operations

4. hash_test.go - Cryptographic Hash Tests

• TestSHA256Simple: SHA-256 implementation with known test vectors
• TestTaggedSHA256: BIP-340 tagged SHA-256 implementation
• TestTaggedSHA256Specification: Compliance with BIP-340 specification
• TestHMACDRBG: HMAC-based deterministic random bit generation
• TestRFC6979NonceFunction: RFC 6979 nonce generation for ECDSA
• TestRFC6979WithExtraData: RFC 6979 with additional entropy
• TestHashEdgeCases: Large input handling
• Benchmarks: Performance tests for hash operations

5. ecmult_comprehensive_test.go - Elliptic Curve Multiplication Tests

• TestEcmultGen: Optimized generator multiplication
• TestEcmultGenRandomScalars: Random scalar multiplication tests
• TestEcmultConst: Constant-time scalar multiplication
• TestEcmultConstVsGen: Consistency between multiplication methods
• TestEcmultMulti: Multi-scalar multiplication (Strauss algorithm)
• TestEcmultMultiEdgeCases: Edge cases for multi-scalar multiplication
• TestEcmultMultiWithZeros: Handling zero scalars in multi-multiplication
• TestEcmultProperties: Mathematical properties (linearity)
• TestEcmultDistributivity: Distributive property testing
• TestEcmultLargeScalars: Large scalar handling (near group order)
• TestEcmultNegativeScalars: Negative scalar multiplication
• Benchmarks: Performance tests for multiplication algorithms

6. integration_test.go - End-to-End Integration Tests

• TestECDSASignVerifyWorkflow: Complete ECDSA signing and verification
• TestSignatureSerialization: DER and compact signature formats
• TestPublicKeySerialization: Compressed and uncompressed public key formats
• TestPublicKeyComparison: Lexicographic public key ordering
• TestContextRandomization: Side-channel protection via blinding
• TestMultipleSignatures: Multiple signatures with same key
• TestEdgeCases: Invalid inputs and error conditions
• TestSelftest: Built-in self-test functionality
• TestKnownTestVectors: Verification against known test vectors
• Benchmarks: End-to-end performance measurements

Test Coverage

The test suite covers:

Core Cryptographic Operations

• ✅ Field arithmetic (addition, multiplication, inversion, square root)
• ✅ Scalar arithmetic (addition, multiplication, inversion, halving)
• ✅ Elliptic curve point operations (addition, doubling, negation)
• ✅ Scalar multiplication (generator and arbitrary points)
• ✅ Multi-scalar multiplication
• ✅ Hash functions (SHA-256, tagged SHA-256, HMAC-DRBG)

ECDSA Implementation

• ✅ Key generation and validation
• ✅ Signature generation (RFC 6979 nonces)
• ✅ Signature verification
• ✅ Signature serialization (DER and compact formats)
• ✅ Public key serialization (compressed and uncompressed)

Security Features

• ✅ Constant-time operations
• ✅ Side-channel protection (context randomization)
• ✅ Input validation and error handling
• ✅ Secure memory clearing

Mathematical Properties

• ✅ Group law verification (associativity, commutativity)
• ✅ Field arithmetic properties
• ✅ Scalar arithmetic properties
• ✅ Elliptic curve equation validation

Test Patterns Based on C Implementation

The tests follow patterns from the original C implementation:

1. Property-Based Testing: Random inputs to verify mathematical properties
2. Known Test Vectors: Verification against standardized test cases
3. Edge Case Testing: Boundary conditions and invalid inputs
4. Cross-Verification: Multiple methods producing same results
5. Performance Benchmarking: Timing critical operations
6. Security Testing: Constant-time behavior verification

Implementation Status

Working Tests

• Basic field and scalar operations
• Simple arithmetic operations
• Input validation
• Serialization/deserialization
• Basic ECDSA workflow (with simplified implementations)

Tests Requiring Full Implementation

Some tests currently fail because the underlying mathematical operations need complete implementation:

• Complex field arithmetic (square roots, inversions)
• Full scalar arithmetic (proper modular reduction)
• Complete elliptic curve operations
• Optimized multiplication algorithms

Usage

To run the test suite:

# Run all tests
go test -v ./...

# Run specific test categories
go test -v -run="TestField" ./...
go test -v -run="TestScalar" ./...
go test -v -run="TestGroup" ./...
go test -v -run="TestHash" ./...
go test -v -run="TestEcmult" ./...
go test -v -run="TestECDSA" ./...

# Run benchmarks
go test -bench=. ./...

Benefits

This comprehensive test suite provides:

1. Correctness Verification: Ensures mathematical operations are implemented correctly
2. Regression Testing: Catches bugs introduced during development
3. Performance Monitoring: Tracks performance of critical operations
4. Security Validation: Verifies constant-time behavior and side-channel resistance
5. Compliance Testing: Ensures compatibility with standards (BIP-340, RFC 6979)
6. Documentation: Tests serve as executable specifications

The test suite is designed to grow with the implementation, providing a solid foundation for developing a production-ready secp256k1 library in Go.