sign method
Signs a blob of data, with this identity's private key. @param challenge - challenge to sign with this identity's secretKey, producing a signature
Implementation
@override
Future<BinaryBlob> sign(dynamic challenge) {
final blob = challenge is BinaryBlob
? challenge
: blobFromBuffer(challenge as ByteBuffer);
return ed25519Sign(
req: ED25519SignReq(seed: _seed, message: blob),
);
}