Current File : //usr/lib/python3/dist-packages/nacl/bindings/crypto_sign.py
# Copyright 2013 Donald Stufft and individual contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import Tuple
from nacl import exceptions as exc
from nacl._sodium import ffi, lib
from nacl.exceptions import ensure
crypto_sign_BYTES: int = lib.crypto_sign_bytes()
# crypto_sign_SEEDBYTES = lib.crypto_sign_seedbytes()
crypto_sign_SEEDBYTES: int = lib.crypto_sign_secretkeybytes() // 2
crypto_sign_PUBLICKEYBYTES: int = lib.crypto_sign_publickeybytes()
crypto_sign_SECRETKEYBYTES: int = lib.crypto_sign_secretkeybytes()
crypto_sign_curve25519_BYTES: int = lib.crypto_box_secretkeybytes()
crypto_sign_ed25519ph_STATEBYTES: int = lib.crypto_sign_ed25519ph_statebytes()
def crypto_sign_keypair() -> Tuple[bytes, bytes]:
"""
Returns a randomly generated public key and secret key.
:rtype: (bytes(public_key), bytes(secret_key))
"""
pk = ffi.new("unsigned char[]", crypto_sign_PUBLICKEYBYTES)
sk = ffi.new("unsigned char[]", crypto_sign_SECRETKEYBYTES)
rc = lib.crypto_sign_keypair(pk, sk)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return (
ffi.buffer(pk, crypto_sign_PUBLICKEYBYTES)[:],
ffi.buffer(sk, crypto_sign_SECRETKEYBYTES)[:],
)
def crypto_sign_seed_keypair(seed: bytes) -> Tuple[bytes, bytes]:
"""
Computes and returns the public key and secret key using the seed ``seed``.
:param seed: bytes
:rtype: (bytes(public_key), bytes(secret_key))
"""
if len(seed) != crypto_sign_SEEDBYTES:
raise exc.ValueError("Invalid seed")
pk = ffi.new("unsigned char[]", crypto_sign_PUBLICKEYBYTES)
sk = ffi.new("unsigned char[]", crypto_sign_SECRETKEYBYTES)
rc = lib.crypto_sign_seed_keypair(pk, sk, seed)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return (
ffi.buffer(pk, crypto_sign_PUBLICKEYBYTES)[:],
ffi.buffer(sk, crypto_sign_SECRETKEYBYTES)[:],
)
def crypto_sign(message: bytes, sk: bytes) -> bytes:
"""
Signs the message ``message`` using the secret key ``sk`` and returns the
signed message.
:param message: bytes
:param sk: bytes
:rtype: bytes
"""
signed = ffi.new("unsigned char[]", len(message) + crypto_sign_BYTES)
signed_len = ffi.new("unsigned long long *")
rc = lib.crypto_sign(signed, signed_len, message, len(message), sk)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return ffi.buffer(signed, signed_len[0])[:]
def crypto_sign_open(signed: bytes, pk: bytes) -> bytes:
"""
Verifies the signature of the signed message ``signed`` using the public
key ``pk`` and returns the unsigned message.
:param signed: bytes
:param pk: bytes
:rtype: bytes
"""
message = ffi.new("unsigned char[]", len(signed))
message_len = ffi.new("unsigned long long *")
if (
lib.crypto_sign_open(message, message_len, signed, len(signed), pk)
!= 0
):
raise exc.BadSignatureError("Signature was forged or corrupt")
return ffi.buffer(message, message_len[0])[:]
def crypto_sign_ed25519_pk_to_curve25519(public_key_bytes: bytes) -> bytes:
"""
Converts a public Ed25519 key (encoded as bytes ``public_key_bytes``) to
a public Curve25519 key as bytes.
Raises a ValueError if ``public_key_bytes`` is not of length
``crypto_sign_PUBLICKEYBYTES``
:param public_key_bytes: bytes
:rtype: bytes
"""
if len(public_key_bytes) != crypto_sign_PUBLICKEYBYTES:
raise exc.ValueError("Invalid curve public key")
curve_public_key_len = crypto_sign_curve25519_BYTES
curve_public_key = ffi.new("unsigned char[]", curve_public_key_len)
rc = lib.crypto_sign_ed25519_pk_to_curve25519(
curve_public_key, public_key_bytes
)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return ffi.buffer(curve_public_key, curve_public_key_len)[:]
def crypto_sign_ed25519_sk_to_curve25519(secret_key_bytes: bytes) -> bytes:
"""
Converts a secret Ed25519 key (encoded as bytes ``secret_key_bytes``) to
a secret Curve25519 key as bytes.
Raises a ValueError if ``secret_key_bytes``is not of length
``crypto_sign_SECRETKEYBYTES``
:param secret_key_bytes: bytes
:rtype: bytes
"""
if len(secret_key_bytes) != crypto_sign_SECRETKEYBYTES:
raise exc.ValueError("Invalid curve secret key")
curve_secret_key_len = crypto_sign_curve25519_BYTES
curve_secret_key = ffi.new("unsigned char[]", curve_secret_key_len)
rc = lib.crypto_sign_ed25519_sk_to_curve25519(
curve_secret_key, secret_key_bytes
)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return ffi.buffer(curve_secret_key, curve_secret_key_len)[:]
def crypto_sign_ed25519_sk_to_pk(secret_key_bytes: bytes) -> bytes:
"""
Extract the public Ed25519 key from a secret Ed25519 key (encoded
as bytes ``secret_key_bytes``).
Raises a ValueError if ``secret_key_bytes``is not of length
``crypto_sign_SECRETKEYBYTES``
:param secret_key_bytes: bytes
:rtype: bytes
"""
if len(secret_key_bytes) != crypto_sign_SECRETKEYBYTES:
raise exc.ValueError("Invalid secret key")
return secret_key_bytes[crypto_sign_SEEDBYTES:]
def crypto_sign_ed25519_sk_to_seed(secret_key_bytes: bytes) -> bytes:
"""
Extract the seed from a secret Ed25519 key (encoded
as bytes ``secret_key_bytes``).
Raises a ValueError if ``secret_key_bytes``is not of length
``crypto_sign_SECRETKEYBYTES``
:param secret_key_bytes: bytes
:rtype: bytes
"""
if len(secret_key_bytes) != crypto_sign_SECRETKEYBYTES:
raise exc.ValueError("Invalid secret key")
return secret_key_bytes[:crypto_sign_SEEDBYTES]
class crypto_sign_ed25519ph_state:
"""
State object wrapping the sha-512 state used in ed25519ph computation
"""
__slots__ = ["state"]
def __init__(self) -> None:
self.state: bytes = ffi.new(
"unsigned char[]", crypto_sign_ed25519ph_STATEBYTES
)
rc = lib.crypto_sign_ed25519ph_init(self.state)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
def crypto_sign_ed25519ph_update(
edph: crypto_sign_ed25519ph_state, pmsg: bytes
) -> None:
"""
Update the hash state wrapped in edph
:param edph: the ed25519ph state being updated
:type edph: crypto_sign_ed25519ph_state
:param pmsg: the partial message
:type pmsg: bytes
:rtype: None
"""
ensure(
isinstance(edph, crypto_sign_ed25519ph_state),
"edph parameter must be a ed25519ph_state object",
raising=exc.TypeError,
)
ensure(
isinstance(pmsg, bytes),
"pmsg parameter must be a bytes object",
raising=exc.TypeError,
)
rc = lib.crypto_sign_ed25519ph_update(edph.state, pmsg, len(pmsg))
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
def crypto_sign_ed25519ph_final_create(
edph: crypto_sign_ed25519ph_state, sk: bytes
) -> bytes:
"""
Create a signature for the data hashed in edph
using the secret key sk
:param edph: the ed25519ph state for the data
being signed
:type edph: crypto_sign_ed25519ph_state
:param sk: the ed25519 secret part of the signing key
:type sk: bytes
:return: ed25519ph signature
:rtype: bytes
"""
ensure(
isinstance(edph, crypto_sign_ed25519ph_state),
"edph parameter must be a ed25519ph_state object",
raising=exc.TypeError,
)
ensure(
isinstance(sk, bytes),
"secret key parameter must be a bytes object",
raising=exc.TypeError,
)
ensure(
len(sk) == crypto_sign_SECRETKEYBYTES,
("secret key must be {} bytes long").format(
crypto_sign_SECRETKEYBYTES
),
raising=exc.TypeError,
)
signature = ffi.new("unsigned char[]", crypto_sign_BYTES)
rc = lib.crypto_sign_ed25519ph_final_create(
edph.state, signature, ffi.NULL, sk
)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return ffi.buffer(signature, crypto_sign_BYTES)[:]
def crypto_sign_ed25519ph_final_verify(
edph: crypto_sign_ed25519ph_state, signature: bytes, pk: bytes
) -> bool:
"""
Verify a prehashed signature using the public key pk
:param edph: the ed25519ph state for the data
being verified
:type edph: crypto_sign_ed25519ph_state
:param signature: the signature being verified
:type signature: bytes
:param pk: the ed25519 public part of the signing key
:type pk: bytes
:return: True if the signature is valid
:rtype: boolean
:raises exc.BadSignatureError: if the signature is not valid
"""
ensure(
isinstance(edph, crypto_sign_ed25519ph_state),
"edph parameter must be a ed25519ph_state object",
raising=exc.TypeError,
)
ensure(
isinstance(signature, bytes),
"signature parameter must be a bytes object",
raising=exc.TypeError,
)
ensure(
len(signature) == crypto_sign_BYTES,
("signature must be {} bytes long").format(crypto_sign_BYTES),
raising=exc.TypeError,
)
ensure(
isinstance(pk, bytes),
"public key parameter must be a bytes object",
raising=exc.TypeError,
)
ensure(
len(pk) == crypto_sign_PUBLICKEYBYTES,
("public key must be {} bytes long").format(
crypto_sign_PUBLICKEYBYTES
),
raising=exc.TypeError,
)
rc = lib.crypto_sign_ed25519ph_final_verify(edph.state, signature, pk)
if rc != 0:
raise exc.BadSignatureError("Signature was forged or corrupt")
return True
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