Signing method returns the same signature every time (for a given key and message)

[shea256]

Here's the code I'm using:

var EC = require('elliptic').ec,
    secp256k1 = new EC('secp256k1'),
    sigFormatter = require('ecdsa-sig-formatter')

var privateKeyHex = 'a5c61c6ca7b3e7e55edee68566aeab22e4da26baa285c7bd10e8d2218aa3b229',
    publicKeyHex = '027d28f9951ce46538951e3697c62588a87f1f1f295de4a14fdd4c780fc52cfe69',
    privateKeyObject = secp256k1.keyFromPrivate(privateKeyHex, 'hex'),
    publicKeyObject = secp256k1.keyFromPublic(publicKeyHex, 'hex')

var messageString = 'Hello, World',
    messageBuffer = new Buffer(messageString),
    messageBytes = messageBuffer.toJSON().data

var derSignatureObject = privateKeyObject.sign(messageBytes),
    derSignatureArray = derSignatureObject.toDER(),
    derSignatureBuffer = new Buffer(derSignatureArray),
    joseSignature = sigFormatter.derToJose(derSignatureBuffer, 'ES256')

console.log(derSignatureObject)

var verified = publicKeyObject.verify(messageBytes, derSignatureBuffer)

console.log(verified)

Is there some issue with the method or am I doing something wrong?

Thank you!

[indutny]

This is because I'm using deterministic k generation for signature algorithm: http://tools.ietf.org/html/rfc6979 . Works as intended.

Thanks!

[shea256]

OK thank you!