verifyTonSignature function

VerifyResult verifyTonSignature(VerifyTonSignatureArgs args)

Recompute the exact digest the device signs — the BoC ROOT CELL's representation hash for a transaction, or the TON Connect proof digest sha256(0xFFFF || "ton-connect" || sha256(payload)) — and verify the Ed25519 signature against the linked key.

Implementation

VerifyResult verifyTonSignature(VerifyTonSignatureArgs args) {
  if (args.signature.length != 64) return failed('signature must be 64 bytes');
  if (args.publicKey.length != 32) return failed('public key must be 32 bytes');

  Uint8List digest;
  if (args.dataType == TonDataType.tonProof) {
    digest = sha256(concatBytes([
      Uint8List.fromList([0xff, 0xff]),
      utf8Encode('ton-connect'),
      sha256(args.signData),
    ]));
  } else if (args.dataType == TonDataType.transaction) {
    try {
      digest = bocRootHash(args.signData);
    } on EraSdkError catch (e) {
      return failed('signData is not a readable BoC: ${e.message}');
    }
  } else {
    return failed('unknown dataType ${args.dataType}');
  }

  final ok = ed25519Verify(args.publicKey, digest, args.signature);
  return ok
      ? verified
      : failed('the signature does not belong to this account');
}