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