dart-secp256k1

⚠️ Security notice — please upgrade to ≥ 0.4.0 (important)

Versions ≤ 0.3.0 generated private keys and ECDSA nonces with a biased, low-entropy routine. Keys produced by PrivateKey.generate() on those versions are weaker than intended, and because the same routine produced the signing nonce, a private key can in principle be recovered from a handful of signatures.

• If you only imported existing keys (PrivateKey.fromHex) and never signed with an affected version, your keys are unchanged.
• If you generated a key with this package at ≤ 0.3.0, or signed with any key using ≤ 0.3.0, treat that key as weak: upgrade to ≥ 0.4.0 and rotate to (move any funds to) a freshly generated key.

0.4.0+ samples keys uniformly from Random.secure() and derives nonces deterministically per RFC 6979 (0.4.1 also hardens signature verification).

Pure secp256k1 implement for dart language.

secp256k1 refers to the parameters of the elliptic curve used in Bitcoin's public-key cryptography, and is defined in Standards for Efficient Cryptography (SEC) (Certicom Research, http://www.secg.org/sec2-v2.pdf). Currently Bitcoin uses secp256k1 with the ECDSA algorithm, though the same curve with the same public/private keys can be used in some other algorithms such as Schnorr.

Usage

A simple usage example:

var pk = PrivateKey.fromHex('c37c299bb7f5ffd8d9329d052983342a8c3234ff3b3fa32a292187341f7146d7');
var pub = pk.publicKey;
print(pub.toHex());
print(pub.toCompressedHex());

var messageHash = 'b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9';
var sig = pk.signature(messageHash);
print(sig.verify(pub, messageHash)); // true

Features and bugs

WARN: This lib does not not provide deterministic ECDSA signature!

Please file feature requests and bugs at the issue tracker.