signBytesToBase64 method

String signBytesToBase64(
  1. Uint8List data
)

Implementation

String signBytesToBase64(Uint8List data) {
  final digest = SHA256Digest();
  final hash = digest.process(data);

  final signer = ECDSASigner(null, HMac(SHA256Digest(), 64));
  signer.init(true, PrivateKeyParameter<ECPrivateKey>(_privateKey));

  final sig = signer.generateSignature(hash) as ECSignature;

  final seq = ASN1Sequence();
  seq.add(ASN1Integer(sig.r));
  seq.add(ASN1Integer(sig.s));
  final der = seq.encodedBytes;

  return base64Encode(der);
}