153 lines
5.1 KiB
Python
153 lines
5.1 KiB
Python
# This file is licensed under the BSD 2-Clause License.
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# See https://opensource.org/licenses/BSD-2-Clause for details.
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from ._curve import _Curve
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from Crypto.Math.Numbers import Integer
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from Crypto.Util._raw_api import (load_pycryptodome_raw_lib, VoidPointer,
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SmartPointer)
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def curve25519_curve():
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p = 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffed # 2**255 - 19
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order = 0x1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed
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_curve25519_lib = load_pycryptodome_raw_lib("Crypto.PublicKey._curve25519", """
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typedef void Point;
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int curve25519_new_point(Point **out,
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const uint8_t x[32],
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size_t modsize,
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const void* context);
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int curve25519_clone(Point **P, const Point *Q);
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void curve25519_free_point(Point *p);
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int curve25519_get_x(uint8_t *xb, size_t modsize, Point *p);
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int curve25519_scalar(Point *P, const uint8_t *scalar, size_t scalar_len, uint64_t seed);
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int curve25519_cmp(const Point *ecp1, const Point *ecp2);
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""")
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class EcLib(object):
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new_point = _curve25519_lib.curve25519_new_point
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clone = _curve25519_lib.curve25519_clone
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free_point = _curve25519_lib.curve25519_free_point
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get_x = _curve25519_lib.curve25519_get_x
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scalar = _curve25519_lib.curve25519_scalar
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cmp = _curve25519_lib.curve25519_cmp
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def _validate_x25519_point(point):
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p2 = p * 2
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x1 = 325606250916557431795983626356110631294008115727848805560023387167927233504
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x2 = 39382357235489614581723060781553021112529911719440698176882885853963445705823
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# http://cr.yp.to/ecdh.html#validate
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deny_list = (
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0,
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1,
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x1,
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x2,
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p - 1,
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p,
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p + 1,
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p + x1,
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p + x2,
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p2 - 1,
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p2,
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p2 + 1,
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)
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try:
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valid = point.x not in deny_list
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except ValueError:
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valid = False
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if not valid:
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raise ValueError("Invalid Curve25519 public key")
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curve25519 = _Curve(Integer(p),
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None,
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Integer(order),
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Integer(9),
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None,
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None,
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255,
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"1.3.101.110", # RFC8410
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None,
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"Curve25519",
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None,
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EcLib,
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_validate_x25519_point,
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)
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return curve25519
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def curve448_curve():
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p = 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffeffffffffffffffffffffffffffffffffffffffffffffffffffffffff # 2**448 - 2**224 - 1
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order = 0x3fffffffffffffffffffffffffffffffffffffffffffffffffffffff7cca23e9c44edb49aed63690216cc2728dc58f552378c292ab5844f3
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_curve448_lib = load_pycryptodome_raw_lib("Crypto.PublicKey._curve448", """
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typedef void Curve448Context;
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typedef void Curve448Point;
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int curve448_new_context(Curve448Context **pec_ctx);
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void curve448_free_context(Curve448Context *ec_ctx);
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int curve448_new_point(Curve448Point **out,
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const uint8_t *x,
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size_t len,
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const Curve448Context *ec_ctx);
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void curve448_free_point(Curve448Point *p);
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int curve448_clone(Curve448Point **P, const Curve448Point *Q);
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int curve448_get_x(uint8_t *xb, size_t modsize, const Curve448Point *p);
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int curve448_scalar(Curve448Point *P, const uint8_t *scalar, size_t scalar_len, uint64_t seed);
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int curve448_cmp(const Curve448Point *ecp1, const Curve448Point *ecp2);
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""")
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class EcLib(object):
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new_context = _curve448_lib.curve448_new_context
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free_context = _curve448_lib.curve448_free_context
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new_point = _curve448_lib.curve448_new_point
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clone = _curve448_lib.curve448_clone
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free_point = _curve448_lib.curve448_free_point
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get_x = _curve448_lib.curve448_get_x
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scalar = _curve448_lib.curve448_scalar
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cmp = _curve448_lib.curve448_cmp
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curve448_context = VoidPointer()
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result = EcLib.new_context(curve448_context.address_of())
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if result:
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raise ImportError("Error %d initializing Curve448 context" % result)
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def _validate_x448_point(point):
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deny_list = (
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0,
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1,
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p - 1,
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p,
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p + 1,
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)
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try:
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valid = point.x not in deny_list
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except ValueError:
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valid = False
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if not valid:
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raise ValueError("Invalid Curve448 public key")
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curve448 = _Curve(Integer(p),
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None,
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Integer(order),
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Integer(5),
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None,
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None,
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448,
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"1.3.101.111", # RFC8410
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SmartPointer(curve448_context.get(), EcLib.free_context),
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"Curve448",
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None,
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EcLib,
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_validate_x448_point,
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)
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return curve448
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