secp256k1 0.4.1

Pure secp256k1 signature algorithm implement for dart language which uses pure dart and basic types to represent all matters

0.4.1

• Fix verify to combine points through the infinity-aware _pointAdd, so malformed signatures (e.g. e == 0, or u1*G == -(u2*Q)) return false instead of throwing from the raw affine helpers.
• isOnCurve takes the curve constant b as an optional parameter (defaulting to the secp256k1 value) instead of always using the global.

0.4.0

• SECURITY (critical): replace private-key and nonce generation. The old getPrivKeyByRand produced low-entropy, structured keys, and sign reused it for the ECDSA nonce — allowing key recovery. Keys are now sampled uniformly from Random.secure(), and the nonce is derived deterministically per RFC 6979 (HMAC-SHA256).
• SECURITY: sign normalizes to low-S (BIP-62).
• SECURITY: verify and the uncompressed public-key parser reject points that are not on the curve.
• Fix inverseMulti: use exact BigInt.modInverse instead of a double-precision quotient that lost precision for 256-bit values.
• getPointByBig now uses a Montgomery ladder (constant-shape point operations).
• Add crypto dependency; allow Dart 3.

0.3.0

• implement null safety (from @andrebianchessi)
• require dart sdk>=2.12.0

0.2.2

• add == operator
• optimize codes

0.2.1

• Fix PrivateKey.generate()

0.2.0

• Rewrite the interface in OOP

0.1.1

• Add simple docstring
• Fix prefix of compressed public key hex

0.1.0

• Pass a basic test
• Initial version, created by Stagehand