CasperSecurity
# Copyright 2018 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 nacl import exceptions as exc
from nacl._sodium import ffi, lib
from nacl.exceptions import ensure
has_crypto_core_ed25519 = bool(lib.PYNACL_HAS_CRYPTO_CORE_ED25519)
crypto_core_ed25519_BYTES = 0
crypto_core_ed25519_SCALARBYTES = 0
crypto_core_ed25519_NONREDUCEDSCALARBYTES = 0
if has_crypto_core_ed25519:
crypto_core_ed25519_BYTES = lib.crypto_core_ed25519_bytes()
crypto_core_ed25519_SCALARBYTES = lib.crypto_core_ed25519_scalarbytes()
crypto_core_ed25519_NONREDUCEDSCALARBYTES = (
lib.crypto_core_ed25519_nonreducedscalarbytes()
)
def crypto_core_ed25519_is_valid_point(p: bytes) -> bool:
"""
Check if ``p`` represents a point on the edwards25519 curve, in canonical
form, on the main subgroup, and that the point doesn't have a small order.
:param p: a :py:data:`.crypto_core_ed25519_BYTES` long bytes sequence
representing a point on the edwards25519 curve
:type p: bytes
:return: point validity
:rtype: bool
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(p, bytes) and len(p) == crypto_core_ed25519_BYTES,
"Point must be a crypto_core_ed25519_BYTES long bytes sequence",
raising=exc.TypeError,
)
rc = lib.crypto_core_ed25519_is_valid_point(p)
return rc == 1
def crypto_core_ed25519_add(p: bytes, q: bytes) -> bytes:
"""
Add two points on the edwards25519 curve.
:param p: a :py:data:`.crypto_core_ed25519_BYTES` long bytes sequence
representing a point on the edwards25519 curve
:type p: bytes
:param q: a :py:data:`.crypto_core_ed25519_BYTES` long bytes sequence
representing a point on the edwards25519 curve
:type q: bytes
:return: a point on the edwards25519 curve represented as
a :py:data:`.crypto_core_ed25519_BYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(p, bytes)
and isinstance(q, bytes)
and len(p) == crypto_core_ed25519_BYTES
and len(q) == crypto_core_ed25519_BYTES,
"Each point must be a {} long bytes sequence".format(
"crypto_core_ed25519_BYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_BYTES)
rc = lib.crypto_core_ed25519_add(r, p, q)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return ffi.buffer(r, crypto_core_ed25519_BYTES)[:]
def crypto_core_ed25519_sub(p: bytes, q: bytes) -> bytes:
"""
Subtract a point from another on the edwards25519 curve.
:param p: a :py:data:`.crypto_core_ed25519_BYTES` long bytes sequence
representing a point on the edwards25519 curve
:type p: bytes
:param q: a :py:data:`.crypto_core_ed25519_BYTES` long bytes sequence
representing a point on the edwards25519 curve
:type q: bytes
:return: a point on the edwards25519 curve represented as
a :py:data:`.crypto_core_ed25519_BYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(p, bytes)
and isinstance(q, bytes)
and len(p) == crypto_core_ed25519_BYTES
and len(q) == crypto_core_ed25519_BYTES,
"Each point must be a {} long bytes sequence".format(
"crypto_core_ed25519_BYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_BYTES)
rc = lib.crypto_core_ed25519_sub(r, p, q)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return ffi.buffer(r, crypto_core_ed25519_BYTES)[:]
def crypto_core_ed25519_scalar_invert(s: bytes) -> bytes:
"""
Return the multiplicative inverse of integer ``s`` modulo ``L``,
i.e an integer ``i`` such that ``s * i = 1 (mod L)``, where ``L``
is the order of the main subgroup.
Raises a ``exc.RuntimeError`` if ``s`` is the integer zero.
:param s: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type s: bytes
:return: an integer represented as a
:py:data:`.crypto_core_ed25519_SCALARBYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(s, bytes) and len(s) == crypto_core_ed25519_SCALARBYTES,
"Integer s must be a {} long bytes sequence".format(
"crypto_core_ed25519_SCALARBYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_SCALARBYTES)
rc = lib.crypto_core_ed25519_scalar_invert(r, s)
ensure(rc == 0, "Unexpected library error", raising=exc.RuntimeError)
return ffi.buffer(r, crypto_core_ed25519_SCALARBYTES)[:]
def crypto_core_ed25519_scalar_negate(s: bytes) -> bytes:
"""
Return the integer ``n`` such that ``s + n = 0 (mod L)``, where ``L``
is the order of the main subgroup.
:param s: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type s: bytes
:return: an integer represented as a
:py:data:`.crypto_core_ed25519_SCALARBYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(s, bytes) and len(s) == crypto_core_ed25519_SCALARBYTES,
"Integer s must be a {} long bytes sequence".format(
"crypto_core_ed25519_SCALARBYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_SCALARBYTES)
lib.crypto_core_ed25519_scalar_negate(r, s)
return ffi.buffer(r, crypto_core_ed25519_SCALARBYTES)[:]
def crypto_core_ed25519_scalar_complement(s: bytes) -> bytes:
"""
Return the complement of integer ``s`` modulo ``L``, i.e. an integer
``c`` such that ``s + c = 1 (mod L)``, where ``L`` is the order of
the main subgroup.
:param s: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type s: bytes
:return: an integer represented as a
:py:data:`.crypto_core_ed25519_SCALARBYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(s, bytes) and len(s) == crypto_core_ed25519_SCALARBYTES,
"Integer s must be a {} long bytes sequence".format(
"crypto_core_ed25519_SCALARBYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_SCALARBYTES)
lib.crypto_core_ed25519_scalar_complement(r, s)
return ffi.buffer(r, crypto_core_ed25519_SCALARBYTES)[:]
def crypto_core_ed25519_scalar_add(p: bytes, q: bytes) -> bytes:
"""
Add integers ``p`` and ``q`` modulo ``L``, where ``L`` is the order of
the main subgroup.
:param p: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type p: bytes
:param q: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type q: bytes
:return: an integer represented as a
:py:data:`.crypto_core_ed25519_SCALARBYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(p, bytes)
and isinstance(q, bytes)
and len(p) == crypto_core_ed25519_SCALARBYTES
and len(q) == crypto_core_ed25519_SCALARBYTES,
"Each integer must be a {} long bytes sequence".format(
"crypto_core_ed25519_SCALARBYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_SCALARBYTES)
lib.crypto_core_ed25519_scalar_add(r, p, q)
return ffi.buffer(r, crypto_core_ed25519_SCALARBYTES)[:]
def crypto_core_ed25519_scalar_sub(p: bytes, q: bytes) -> bytes:
"""
Subtract integers ``p`` and ``q`` modulo ``L``, where ``L`` is the
order of the main subgroup.
:param p: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type p: bytes
:param q: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type q: bytes
:return: an integer represented as a
:py:data:`.crypto_core_ed25519_SCALARBYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(p, bytes)
and isinstance(q, bytes)
and len(p) == crypto_core_ed25519_SCALARBYTES
and len(q) == crypto_core_ed25519_SCALARBYTES,
"Each integer must be a {} long bytes sequence".format(
"crypto_core_ed25519_SCALARBYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_SCALARBYTES)
lib.crypto_core_ed25519_scalar_sub(r, p, q)
return ffi.buffer(r, crypto_core_ed25519_SCALARBYTES)[:]
def crypto_core_ed25519_scalar_mul(p: bytes, q: bytes) -> bytes:
"""
Multiply integers ``p`` and ``q`` modulo ``L``, where ``L`` is the
order of the main subgroup.
:param p: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type p: bytes
:param q: a :py:data:`.crypto_core_ed25519_SCALARBYTES`
long bytes sequence representing an integer
:type q: bytes
:return: an integer represented as a
:py:data:`.crypto_core_ed25519_SCALARBYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(p, bytes)
and isinstance(q, bytes)
and len(p) == crypto_core_ed25519_SCALARBYTES
and len(q) == crypto_core_ed25519_SCALARBYTES,
"Each integer must be a {} long bytes sequence".format(
"crypto_core_ed25519_SCALARBYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_SCALARBYTES)
lib.crypto_core_ed25519_scalar_mul(r, p, q)
return ffi.buffer(r, crypto_core_ed25519_SCALARBYTES)[:]
def crypto_core_ed25519_scalar_reduce(s: bytes) -> bytes:
"""
Reduce integer ``s`` to ``s`` modulo ``L``, where ``L`` is the order
of the main subgroup.
:param s: a :py:data:`.crypto_core_ed25519_NONREDUCEDSCALARBYTES`
long bytes sequence representing an integer
:type s: bytes
:return: an integer represented as a
:py:data:`.crypto_core_ed25519_SCALARBYTES` long bytes sequence
:rtype: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_core_ed25519,
"Not available in minimal build",
raising=exc.UnavailableError,
)
ensure(
isinstance(s, bytes)
and len(s) == crypto_core_ed25519_NONREDUCEDSCALARBYTES,
"Integer s must be a {} long bytes sequence".format(
"crypto_core_ed25519_NONREDUCEDSCALARBYTES"
),
raising=exc.TypeError,
)
r = ffi.new("unsigned char[]", crypto_core_ed25519_SCALARBYTES)
lib.crypto_core_ed25519_scalar_reduce(r, s)
return ffi.buffer(r, crypto_core_ed25519_SCALARBYTES)[:]