Cip8

class cometa.message_signing.CIP8SignResult(cose_sign1, cose_key)

Bases: object

Result of a CIP-8 message signing operation.

Contains the COSE_Sign1 and COSE_Key structures as CBOR-encoded bytes.

Parameters:

• cose_sign1 (bytes)

• cose_key (bytes)

cose_sign1

The CBOR-encoded COSE_Sign1 structure containing the signature.

cose_key

The CBOR-encoded COSE_Key structure containing the public key.

__init__(cose_sign1, cose_key)

Parameters:

• cose_sign1 (bytes)

• cose_key (bytes)

Return type:

None

__repr__()

Return repr(self).

Return type:

str

---

cometa.message_signing.cip8.sign(message, address, signing_key)

Signs arbitrary data using CIP-8 / COSE and binds the signature to a Cardano address.

This function creates a COSE_Sign1 and COSE_Key structure compatible with CIP-8 and the CIP-30 signData API. The message is signed directly (no pre-hashing), with the CIP-8 “hashed” flag set to false and an empty external_aad.

The protected headers include:

• alg: EdDSA (-8)

• address: raw bytes of the address

Parameters:

• message (bytes) – The message bytes to sign.

• address (Address) – Cardano address to bind the signature to.

• signing_key (Ed25519PrivateKey) – Ed25519 private key used to produce the signature.

Returns:

A CIP8SignResult containing the CBOR-encoded COSE_Sign1 and COSE_Key structures.

Raises:

CardanoError – If signing fails.

Return type:

CIP8SignResult

Example

>>> from cometa import Ed25519PrivateKey, Address
>>> private_key = Ed25519PrivateKey.generate()
>>> address = Address.from_bech32("addr1...")
>>> result = sign(b"Hello, Cardano!", address, private_key)
>>> result.cose_sign1  # CBOR-encoded COSE_Sign1
b'...'

---

cometa.message_signing.cip8.sign_with_key_hash(message, key_hash, signing_key)

Signs arbitrary data using CIP-8 / COSE and binds the signature to a key hash.

This function creates a COSE_Sign1 and COSE_Key structure compatible with CIP-8 and the CIP-30 signData API, binding the signature to a key hash rather than a full Cardano address. The message is signed directly (no pre-hashing), with the CIP-8 “hashed” flag set to false and an empty external_aad.

The protected headers include:

• alg: EdDSA (-8)

• keyHash: raw bytes of the key hash

Parameters:

• message (bytes) – The message bytes to sign.

• key_hash (Blake2bHash) – Key hash to bind the signature to (typically a Blake2b-224 hash of a public key).

• signing_key (Ed25519PrivateKey) – Ed25519 private key used to produce the signature.

Returns:

A CIP8SignResult containing the CBOR-encoded COSE_Sign1 and COSE_Key structures.

Raises:

CardanoError – If signing fails.

Return type:

CIP8SignResult

Example

>>> from cometa import Ed25519PrivateKey, Blake2bHash
>>> private_key = Ed25519PrivateKey.generate()
>>> key_hash = private_key.get_public_key().to_hash()
>>> result = sign_with_key_hash(b"Hello, dRep!", key_hash, private_key)
>>> result.cose_sign1  # CBOR-encoded COSE_Sign1
b'...'