[AVLE] Signing Image issue Resolved!

I was in trouble to sign an image.
[AVLE] Image Upload - Signing Image not working

Through arduous efforts, I managed to sign an image!

There was no way to pass a data of dart to the Buffer data of javascipt.

So, I changed the dsteem source code to accept Uint8List of Dart which is the Buffer!

This is the modified sign function of dsteem's crypto.ts file.

// crypto.ts of dsteem
  public sign(message: any): Signature {
    // for avle, need to pass Uint8List
    const msgBuf = Buffer.from(message);
    let rv: { signature: Buffer; recovery: number };
    let attempts = 0;
    do {
      const options = {
        data: sha256(Buffer.concat([msgBuf, Buffer.alloc(1, ++attempts)])),
      };
      rv = secp256k1.sign(msgBuf, this.key, options);
    } while (!isCanonicalSignature(rv.signature));
    return new Signature(rv.signature, rv.recovery);
  }

And the following is the signMessage function in Dart side:

String? signMessage({required Uint8List data, required String wifKey}) {
  try {
    // create a private key instance
    final privateKey = PrivateKey.fromString(wifKey);
    // create a buffer
    final dataBuffer = BytesBuilder();
    // prefix string to sign
    final prefix = 'ImageSigningChallenge';
    // write the prefix data in the buffer
    dataBuffer.add(utf8.encode(prefix) as Uint8List);
    // add data in the buffer
    dataBuffer.add(data);
    // hash the buffer data
    final hash = sha256.convert(dataBuffer.toBytes()).bytes as Uint8List;
    print('hash: $hash');
    final signature = privateKey.sign(hash);
} catch (error) {
    print('failed to sign message');
}
}

Now the signing and uploading an image are smooth!

After signing the image, then we can get the url of the image!

Resteem / Vote / Comment / Follow / Support

This project will Make STEEM Great Again! I, the developer of PLAY STEEM mobile app, am doing my best to bring people to the STEEM ecosystem.

cc.
@steemcurator01

Thank you for your support!