先零散的记一下，后面再整理

js ecc

https://github.com/EOSIO/eosjs-ecc/blob/7ec577cad54e17da6168fdfb11ec2b09d6f0e7f0/src/signature.js

sign

https://github.com/EOSIO/eosjs-ecc/blob/7ec577cad54e17da6168fdfb11ec2b09d6f0e7f0/src/signature.js#L177

Signature.sign = function(data, privateKey, encoding = 'utf8') {
    if(typeof data === 'string') {
        data = Buffer.from(data, encoding)
    }
    assert(Buffer.isBuffer(data), 'data is a required String or Buffer')
    data = hash.sha256(data)
    return Signature.signHash(data, privateKey)
}

https://github.com/EOSIO/eosjs-ecc/blob/7ec577cad54e17da6168fdfb11ec2b09d6f0e7f0/src/signature.js#L210

 ecsignature = ecdsa.sign(curve, dataSha256, privateKey.d, nonce++);

java

https://github.com/adyliu/jeos/blob/53dbd027cd59d367d9a197cbff5a58bdd9bf7195/src/main/java/io/jafka/jeos/impl/LocalApiImpl.java#L68

private String sign(String privateKey, SignArg arg, PackedTransaction t) {
    Raw raw = Packer.packPackedTransaction(arg.getChainId(), t);
    raw.pack(ByteBuffer.allocate(33).array());// TODO: what's this?
    String hash = KeyUtil.signHash(privateKey, raw.bytes());
    return hash;
}

https://github.com/adyliu/jeos/blob/4eaa9fb4555129f3d0baa56e7ffb70cac213a009/src/main/java/io/jafka/jeos/util/ecc/Ecdsa.java

https://github.com/starkbank/ecdsa-java/blob/master/src/main/java/com/starkbank/ellipticcurve/Ecdsa.java

参考

ECDSA — The art of cryptographic signatures
https://medium.com/coinmonks/ecdsa-the-art-of-cryptographic-signatures-d0bb254c8b96