def sign_recoverable(self,
message: bytes,
hasher: Hasher = sha256,
custom_nonce: Nonce = DEFAULT_NONCE) -> bytes:
"""
Create a recoverable ECDSA signature.
:param message: The message to sign.
:param hasher: The hash function to use, which must return 32 bytes. By default,
the `sha256` algorithm is used. If `None`, no hashing occurs.
:param custom_nonce: Custom nonce data in the form `(nonce_function, input_data)`. Refer to
[secp256k1_recovery.h](https://github.com/bitcoin-core/secp256k1/blob/f8c0b57e6ba202b1ce7c5357688de97c9c067697/include/secp256k1_recovery.h#L78-L79).
:return: The recoverable ECDSA signature.
:raises ValueError: If the message hash was not 32 bytes long, the nonce generation
function failed, or the private key was invalid.
"""
msg_hash = hasher(message) if hasher is not None else message
if len(msg_hash) != 32:
raise ValueError('Message hash must be 32 bytes long.')
signature = ffi.new('secp256k1_ecdsa_recoverable_signature *')
nonce_fn, nonce_data = custom_nonce
signed = lib.secp256k1_ecdsa_sign_recoverable(self.context.ctx,
signature, msg_hash,
self.secret, nonce_fn,
nonce_data)
if not signed:
raise ValueError(
'The nonce generation function failed, or the private key was invalid.'
)
return serialize_recoverable(signature, self.context)
def sign_recoverable(self, message, hasher=sha256):
msg_hash = hasher(message) if hasher is not None else message
if len(msg_hash) != 32:
raise ValueError('Message hash must be 32 bytes long.')
signature = ffi.new('secp256k1_ecdsa_recoverable_signature *')
signed = lib.secp256k1_ecdsa_sign_recoverable(
self.context.ctx, signature, msg_hash, self.secret, ffi.NULL, ffi.NULL
)
if not signed:
raise ValueError('The nonce generation function failed, or the private key was invalid.')
return serialize_recoverable(signature, self.context)