241 lines
8.1 KiB
Python
241 lines
8.1 KiB
Python
# Copyright 2013-2018 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 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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has_crypto_scalarmult_ed25519 = bool(lib.PYNACL_HAS_CRYPTO_SCALARMULT_ED25519)
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crypto_scalarmult_BYTES: int = lib.crypto_scalarmult_bytes()
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crypto_scalarmult_SCALARBYTES: int = lib.crypto_scalarmult_scalarbytes()
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crypto_scalarmult_ed25519_BYTES = 0
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crypto_scalarmult_ed25519_SCALARBYTES = 0
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if has_crypto_scalarmult_ed25519:
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crypto_scalarmult_ed25519_BYTES = lib.crypto_scalarmult_ed25519_bytes()
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crypto_scalarmult_ed25519_SCALARBYTES = (
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lib.crypto_scalarmult_ed25519_scalarbytes()
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)
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def crypto_scalarmult_base(n: bytes) -> bytes:
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"""
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Computes and returns the scalar product of a standard group element and an
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integer ``n``.
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:param n: bytes
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:rtype: bytes
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"""
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q = ffi.new("unsigned char[]", crypto_scalarmult_BYTES)
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rc = lib.crypto_scalarmult_base(q, n)
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ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
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return ffi.buffer(q, crypto_scalarmult_SCALARBYTES)[:]
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def crypto_scalarmult(n: bytes, p: bytes) -> bytes:
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"""
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Computes and returns the scalar product of the given group element and an
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integer ``n``.
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:param p: bytes
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:param n: bytes
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:rtype: bytes
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"""
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q = ffi.new("unsigned char[]", crypto_scalarmult_BYTES)
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rc = lib.crypto_scalarmult(q, n, p)
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ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
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return ffi.buffer(q, crypto_scalarmult_SCALARBYTES)[:]
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def crypto_scalarmult_ed25519_base(n: bytes) -> bytes:
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"""
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Computes and returns the scalar product of a standard group element and an
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integer ``n`` on the edwards25519 curve.
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:param n: a :py:data:`.crypto_scalarmult_ed25519_SCALARBYTES` long bytes
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sequence representing a scalar
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:type n: bytes
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:return: a point on the edwards25519 curve, represented as a
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:py:data:`.crypto_scalarmult_ed25519_BYTES` long bytes sequence
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:rtype: bytes
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:raises nacl.exceptions.UnavailableError: If called when using a
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minimal build of libsodium.
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"""
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ensure(
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has_crypto_scalarmult_ed25519,
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"Not available in minimal build",
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raising=exc.UnavailableError,
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)
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ensure(
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isinstance(n, bytes)
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and len(n) == crypto_scalarmult_ed25519_SCALARBYTES,
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"Input must be a {} long bytes sequence".format(
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"crypto_scalarmult_ed25519_SCALARBYTES"
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),
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raising=exc.TypeError,
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)
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q = ffi.new("unsigned char[]", crypto_scalarmult_ed25519_BYTES)
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rc = lib.crypto_scalarmult_ed25519_base(q, n)
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ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
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return ffi.buffer(q, crypto_scalarmult_ed25519_BYTES)[:]
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def crypto_scalarmult_ed25519_base_noclamp(n: bytes) -> bytes:
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"""
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Computes and returns the scalar product of a standard group element and an
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integer ``n`` on the edwards25519 curve. The integer ``n`` is not clamped.
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:param n: a :py:data:`.crypto_scalarmult_ed25519_SCALARBYTES` long bytes
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sequence representing a scalar
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:type n: bytes
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:return: a point on the edwards25519 curve, represented as a
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:py:data:`.crypto_scalarmult_ed25519_BYTES` long bytes sequence
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:rtype: bytes
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:raises nacl.exceptions.UnavailableError: If called when using a
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minimal build of libsodium.
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"""
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ensure(
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has_crypto_scalarmult_ed25519,
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"Not available in minimal build",
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raising=exc.UnavailableError,
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)
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ensure(
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isinstance(n, bytes)
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and len(n) == crypto_scalarmult_ed25519_SCALARBYTES,
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"Input must be a {} long bytes sequence".format(
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"crypto_scalarmult_ed25519_SCALARBYTES"
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),
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raising=exc.TypeError,
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)
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q = ffi.new("unsigned char[]", crypto_scalarmult_ed25519_BYTES)
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rc = lib.crypto_scalarmult_ed25519_base_noclamp(q, n)
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ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
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return ffi.buffer(q, crypto_scalarmult_ed25519_BYTES)[:]
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def crypto_scalarmult_ed25519(n: bytes, p: bytes) -> bytes:
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"""
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Computes and returns the scalar product of a *clamped* integer ``n``
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and the given group element on the edwards25519 curve.
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The scalar is clamped, as done in the public key generation case,
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by setting to zero the bits in position [0, 1, 2, 255] and setting
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to one the bit in position 254.
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:param n: a :py:data:`.crypto_scalarmult_ed25519_SCALARBYTES` long bytes
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sequence representing a scalar
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:type n: bytes
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:param p: a :py:data:`.crypto_scalarmult_ed25519_BYTES` long bytes sequence
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representing a point on the edwards25519 curve
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:type p: bytes
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:return: a point on the edwards25519 curve, represented as a
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:py:data:`.crypto_scalarmult_ed25519_BYTES` long bytes sequence
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:rtype: bytes
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:raises nacl.exceptions.UnavailableError: If called when using a
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minimal build of libsodium.
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"""
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ensure(
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has_crypto_scalarmult_ed25519,
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"Not available in minimal build",
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raising=exc.UnavailableError,
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)
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ensure(
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isinstance(n, bytes)
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and len(n) == crypto_scalarmult_ed25519_SCALARBYTES,
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"Input must be a {} long bytes sequence".format(
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"crypto_scalarmult_ed25519_SCALARBYTES"
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),
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raising=exc.TypeError,
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)
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ensure(
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isinstance(p, bytes) and len(p) == crypto_scalarmult_ed25519_BYTES,
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"Input must be a {} long bytes sequence".format(
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"crypto_scalarmult_ed25519_BYTES"
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),
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raising=exc.TypeError,
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)
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q = ffi.new("unsigned char[]", crypto_scalarmult_ed25519_BYTES)
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rc = lib.crypto_scalarmult_ed25519(q, n, p)
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ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
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return ffi.buffer(q, crypto_scalarmult_ed25519_BYTES)[:]
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def crypto_scalarmult_ed25519_noclamp(n: bytes, p: bytes) -> bytes:
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"""
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Computes and returns the scalar product of an integer ``n``
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and the given group element on the edwards25519 curve. The integer
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``n`` is not clamped.
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:param n: a :py:data:`.crypto_scalarmult_ed25519_SCALARBYTES` long bytes
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sequence representing a scalar
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:type n: bytes
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:param p: a :py:data:`.crypto_scalarmult_ed25519_BYTES` long bytes sequence
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representing a point on the edwards25519 curve
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:type p: bytes
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:return: a point on the edwards25519 curve, represented as a
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:py:data:`.crypto_scalarmult_ed25519_BYTES` long bytes sequence
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:rtype: bytes
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:raises nacl.exceptions.UnavailableError: If called when using a
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minimal build of libsodium.
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"""
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ensure(
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has_crypto_scalarmult_ed25519,
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"Not available in minimal build",
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raising=exc.UnavailableError,
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)
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ensure(
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isinstance(n, bytes)
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and len(n) == crypto_scalarmult_ed25519_SCALARBYTES,
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"Input must be a {} long bytes sequence".format(
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"crypto_scalarmult_ed25519_SCALARBYTES"
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),
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raising=exc.TypeError,
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)
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ensure(
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isinstance(p, bytes) and len(p) == crypto_scalarmult_ed25519_BYTES,
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"Input must be a {} long bytes sequence".format(
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"crypto_scalarmult_ed25519_BYTES"
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),
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raising=exc.TypeError,
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)
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q = ffi.new("unsigned char[]", crypto_scalarmult_ed25519_BYTES)
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rc = lib.crypto_scalarmult_ed25519_noclamp(q, n, p)
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ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
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return ffi.buffer(q, crypto_scalarmult_ed25519_BYTES)[:]
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