CIP-008¶

cardano_error_t cardano_cip8_sign(const byte_t *message, size_t message_size, const cardano_address_t *address, const cardano_ed25519_private_key_t *signing_key, cardano_buffer_t **cose_sign1_out, cardano_buffer_t **cose_key_out)¶

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 address

The resulting cose_sign1_out and cose_key_out buffers contain CBOR-encoded COSE structures.

const byte_t message[] = "Hello, Cardano!";
cardano_address_t* address = // previously constructed
cardano_ed25519_private_key_t* sk = // derived key;

cardano_buffer_t* cose_sign1 = NULL;
cardano_buffer_t* cose_key   = NULL;

cardano_error_t result = cardano_cip8_sign(
  message,
  sizeof(message) - 1,
  address,
  sk,
  &cose_sign1,
  &cose_key);

if (result != CARDANO_SUCCESS)
{
  // handle error...
}

cardano_buffer_unref(&cose_sign1);
cardano_buffer_unref(&cose_key);

Parameters:¶

const byte_t *message¶: [in] Pointer to the message bytes to sign.
size_t message_size¶: [in] Size of message in bytes.
const cardano_address_t *address¶: [in] Cardano address to bind the signature to. Must not be NULL. If you need to bind the signature to a key hash instead, use cardano_cip8_sign_ex.
const cardano_ed25519_private_key_t *signing_key¶: [in] Ed25519 private key used to produce the signature. Must not be NULL.
cardano_buffer_t **cose_sign1_out¶: [out] On success, receives a newly allocated buffer containing the CBOR-encoded COSE_Sign1 structure.
cardano_buffer_t **cose_key_out¶: [out] On success, receives a newly allocated buffer containing the CBOR-encoded COSE_Key structure corresponding to signing_key.

Returns:¶

CARDANO_SUCCESS on success, or an error code on failure.

Post:¶

On success, the caller owns cose_sign1_out and cose_key_out and must release them with cardano_buffer_unref().

cardano_error_t cardano_cip8_sign_ex(const byte_t *message, size_t message_size, const cardano_blake2b_hash_t *key_hash, const cardano_ed25519_private_key_t *signing_key, cardano_buffer_t **cose_sign1_out, cardano_buffer_t **cose_key_out)¶

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.