decodeVerKeyDSIGN: wrong length, expected 32 bytes but got 0

[robinboening]

I am trying to make a simple transaction (lovelace only) using generated payment keys.

CHAIN_CONTEXT = BlockFrostChainContext(
  project_id=BLOCKFROST_PROJECT_ID,
  network=Network.TESTNET,
  base_url="https://cardano-preprod.blockfrost.io/api",
)

payment_key_pair = PaymentKeyPair.generate()
payment_signing_key = payment_key_pair.signing_key
payment_verification_key = payment_key_pair.verification_key

stake_key_pair = StakeKeyPair.generate()
stake_signing_key = stake_key_pair.signing_key
stake_verification_key = stake_key_pair.verification_key

address = Address(payment_part=payment_verification_key.hash(),
                         staking_part=stake_verification_key.hash(),
                         network=Network.TESTNET)

toAddress = "..."
...
builder = TransactionBuilder(CHAIN_CONTEXT)
builder.add_input_address(address)
builder.add_output(TransactionOutput.from_primitive([toAddress, 10000000]))
builder.build_and_sign([payment_signing_key], change_address=address)

The tx can be built, but submitting it to Blockfrost throws this error

blockfrost.utils.ApiError: {'error': 'Bad Request', 'message': '"transaction read error RawCborDecodeError [DecoderErrorDeserialiseFailure \\"Byron Tx\\" (DeserialiseFailure 1 \\"Size mismatch when decoding TxAux.\\\\nExpected 2, but found 4.\\"),DecoderErrorDeserialiseFailure \\"Shelley Tx\\" (DeserialiseFailure 1 \\"Size mismatch when decoding \\\\nRecord RecD.\\\\nExpected 4, but found 3.\\"),DecoderErrorDeserialiseFailure \\"Shelley Tx\\" (DeserialiseFailure 1 \\"Size mismatch when decoding \\\\nRecord RecD.\\\\nExpected 4, but found 3.\\"),DecoderErrorDeserialiseFailure \\"Shelley Tx\\" (DeserialiseFailure 1 \\"Size mismatch when decoding \\\\nRecord RecD.\\\\nExpected 4, but found 3.\\"),DecoderErrorDeserialiseFailure \\"Shelley Tx\\" (DeserialiseFailure 193 \\"decodeVerKeyDSIGN: wrong length, expected 32 bytes but got 0\\"),DecoderErrorDeserialiseFailure \\"Shelley Tx\\" (Deseria', 'status_code': 400}

I can see it hast to do with the verification key and I bet I am doing something wrong. Any idea what it is? 🙇

[cffls]

Hi Robin, the code looks correct to me. Could you provide the CBOR, which can help debugging? It will be great if you can also provide the code that submits the transaction cbor.

[robinboening]

Hey Jerry,

the cbor looks like this

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

and the submission is simple as this

tx = builder.build_and_sign([payment_signing_key], change_address=address)
CHAIN_CONTEXT.submit_tx(tx.to_cbor())

[cffls]

Thanks, this is very helpful. What I found is that the verification key in the witness of cbor is empty.

echo 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 | xxd -r -p | base64 | python3 -m cbor2.tool -d | jq
[
  {
    "0": [
      [
        "|\\x80dx\\xff-\\xe0\\xc9pR8p\\xcdW\\xf5\b\\xc0cL\r\\xd0\u0000^\\xf85\\xc1n\\xf7\\xa9\\xc8\u0000\u0018",
        0
      ]
    ],
    "1": [
      [
        "\u0000\\xb5\\xb7\\xe6(\\x99q\\x93\\x88\\xbeH\\xd4\u0012\\xe18C\u0011\\xa6\\x8eD\\xa0\u00163\\xd5\u0018[ :d:tk\\x90\\x9d\\xe8\\xd2\\xe7t|\\xcbv\u0012[%ٍ\u0019\\x8b\\x99P\\xf3\\x9f\\xd7\u000e\\xb35a",
        9995000000
      ],
      [
        "\u0000\\xb5k\\xb1\\xf7\u000f\\xeb82\u0007\\xc9&\\xaf\\x89\\xed\\xe6\\x93O/\\xac\\xa8P7\\xf3ق\\x80\u001eZK\u001a\\xb3\\xfc\\xcc\u0001l\\xcd\\xeb\\xd2\u0000\u0006\\xfe\u0016}N@\\xbd\u001a\u0012\\xf94\\xfd\\xc4\\xddutW",
        4831683
      ]
    ],
    "2": 168317,
    "3": 11317308
  },
  {
    "0": [
      [
        "",    <-------- This is the problem
        "V\\xbe+\\xf9\\xc7æ\\xf8\\xd4)\\xbf\\xe3\u001f뷔\\xb6\\xecL\\xcdd\u0013\\x9d\\xc1y\\xf1V\\x883\u0001\u0005\\xc4ˋ\\xb8\\x86\\xdaT\\xf3\\xff\\xf3\\xb7\\xe3B\\xd8V\\xb6\\x889lY}\"n\\xd6\\xff]*U>\\xcb\u0002\\x94\b"
      ]
    ]
  },
  true,
  null
]

The verification key was created and added to witness set by this line, which calls to_verification_key that yielded an empty vkey. Could you call to_verification_key from signing key directly and check if it is empty?

[robinboening]

Calling to_verification_key on the signing_key returns a proper key

{"type": "PaymentVerificationKeyShelley_ed25519", "description": "PaymentVerificationKeyShelley_ed25519", "cborHex": "5820ae60924a2a814453c0fc57a9a3e685643ed5a6f5af227298cb5105a12f25092e"}

[robinboening]

I tried using v0.6.3 and 0.7.0 by the way

[cffls]

Thanks Robin. Could you try constructing the signed transaction manually like this and share the output? This will help us understand which step went wrong.

...
tx_body = builder.build(change_address=address)
signature = payment_signing_key.sign(tx_body.hash())
vk = payment_signing_key.to_verification_key()
print(vk)
vk_witnesses = [VerificationKeyWitness(vk, signature)]
print(vk_witnesses)
tx = Transaction(tx_body, TransactionWitnessSet(vkey_witnesses=vk_witnesses))
print(tx)
tx_cbor = tx.to_cbor()
print(tx_cbor)

[robinboening]

Thanks for your support Jerry!

This is the entire printed output.

{"type": "PaymentVerificationKeyShelley_ed25519", "description": "PaymentVerificationKeyShelley_ed25519", "cborHex": "5820ae60924a2a814453c0fc57a9a3e685643ed5a6f5af227298cb5105a12f25092e"}
[{
  'signature': b'\xfbwE\xfd\xa1Y\xf2YUN\xd3)\x1d\xfd\x80\xdaA\xbf\x8aY\x9d\xbdG\x8eml\xc1\x06;\xc8N\xfb\x88\x17L\xf3\xb2\xe6\xa0\x11\xbb>\x84\x99\x92\xc7\xa9r\xa6\x03\x03W~\n\xa5q\xb6*l\xc8\x01.v\r',
  'vkey': {"type": "PaymentVerificationKeyShelley_ed25519", "description": "PaymentVerificationKeyShelley_ed25519", "cborHex": "5820ae60924a2a814453c0fc57a9a3e685643ed5a6f5af227298cb5105a12f25092e"},
}]
{
  'auxiliary_data': None,
  'transaction_body': {
    'auxiliary_data_hash': None,
    'certificates': None,
    'collateral': None,
    'collateral_return': None,
    'fee': 168317,
    'inputs': [
      {
        'index': 0,
        'transaction_id': TransactionId(hex='7c806478ff2de0c970523870cd57f508c0634c0dd0005ef835c16ef7a9c80018'),
      },
    ],
    'mint': None,
    'network_id': None,
    'outputs': [
      {
        'address': addr_test1qz6m0e3gn9ce8z97fr2p9cfcgvg6drjy5qtr84gctvsr5ep6w34ep80g6tnhglxtwcf9kfwe35vchx2s7w0awr4nx4sstap56q,
        'amount': {'coin': 10000000, 'multi_asset': {}},
        'datum': None,
        'datum_hash': None,
        'post_alonzo': False,
        'script': None,
      },
      {
        'address': addr_test1qz6khv0hpl4nsvs8eyn2lz0du6f57tav4pgr0u7es2qpukjtr2elenqpdnx7h5sqqmlpvl2wgz735yhexn7ufht4w3tsqx0vgv,
        'amount': {'coin': 9989831683, 'multi_asset': {}},
        'datum': None,
        'datum_hash': None,
        'post_alonzo': False,
        'script': None,
      },
    ],
    'reference_inputs': None,
    'required_signers': None,
    'script_data_hash': None,
    'total_collateral': None,
    'ttl': 11392138,
    'update': None,
    'validity_start': None,
    'withdraws': None,
  },
  'transaction_witness_set': {
    'bootstrap_witness': None,
    'native_scripts': None,
    'plutus_data': None,
    'plutus_v1_script': None,
    'plutus_v2_script': None,
    'redeemer': None,
    'vkey_witnesses': [
      {
        'signature': b'\xfbwE\xfd\xa1Y\xf2YUN\xd3)\x1d\xfd\x80\xdaA\xbf\x8aY\x9d\xbdG\x8eml\xc1\x06;\xc8N\xfb\x88\x17L\xf3\xb2\xe6\xa0\x11\xbb>\x84\x99\x92\xc7\xa9r\xa6\x03\x03W~\n\xa5q\xb6*l\xc8\x01.v\r',
        'vkey': {"type": "PaymentVerificationKeyShelley_ed25519", "description": "PaymentVerificationKeyShelley_ed25519", "cborHex": "5820ae60924a2a814453c0fc57a9a3e685643ed5a6f5af227298cb5105a12f25092e"},
      },
    ],
  },
  'valid': True,
}
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

[cffls]

Thanks Robin! This cbor looks correct. If you submit this transaction, it will go through. It is still a mystery to me why build_and_sign resulted in an empty verification key. Is this issue consistently reproducible?

[robinboening]

Yeah, the tx went through.
Correct, I was consistently getting this error. I've tried about 5-6 times yesterday.

I just put build_and_sign back in, so it is now as it was when I got the error. I tried another transaction and it succeeded! To be honest, now I am completely lost.

[cffls]

Closing this issue as it is not reproducible now. @robinboening If you encounter this problem again, please feel free to reopen this issue.