diff options
Diffstat (limited to 'frozen_deps/Cryptodome/PublicKey/ECC.py')
| -rw-r--r-- | frozen_deps/Cryptodome/PublicKey/ECC.py | 1036 |
1 files changed, 823 insertions, 213 deletions
diff --git a/frozen_deps/Cryptodome/PublicKey/ECC.py b/frozen_deps/Cryptodome/PublicKey/ECC.py index e83664b..84a4e07 100644 --- a/frozen_deps/Cryptodome/PublicKey/ECC.py +++ b/frozen_deps/Cryptodome/PublicKey/ECC.py @@ -31,7 +31,6 @@ from __future__ import print_function import re -import sys import struct import binascii from collections import namedtuple @@ -43,13 +42,15 @@ from Cryptodome.Math.Numbers import Integer from Cryptodome.Util.asn1 import (DerObjectId, DerOctetString, DerSequence, DerBitString) +from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib, VoidPointer, + SmartPointer, c_size_t, c_uint8_ptr, + c_ulonglong, null_pointer) + from Cryptodome.PublicKey import (_expand_subject_public_key_info, _create_subject_public_key_info, _extract_subject_public_key_info) -from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib, VoidPointer, - SmartPointer, c_size_t, c_uint8_ptr, - c_ulonglong) +from Cryptodome.Hash import SHA512, SHAKE256 from Cryptodome.Random import get_random_bytes from Cryptodome.Random.random import getrandbits @@ -70,7 +71,7 @@ int ec_ws_new_point(EcPoint **pecp, const uint8_t *y, size_t len, const EcContext *ec_ctx); -void ec_free_point(EcPoint *ecp); +void ec_ws_free_point(EcPoint *ecp); int ec_ws_get_xy(uint8_t *x, uint8_t *y, size_t len, @@ -82,17 +83,173 @@ int ec_ws_scalar(EcPoint *ecp, size_t len, uint64_t seed); int ec_ws_clone(EcPoint **pecp2, const EcPoint *ecp); -int ec_ws_copy(EcPoint *ecp1, const EcPoint *ecp2); int ec_ws_cmp(const EcPoint *ecp1, const EcPoint *ecp2); int ec_ws_neg(EcPoint *p); -int ec_ws_normalize(EcPoint *ecp); -int ec_ws_is_pai(EcPoint *ecp); """) -_Curve = namedtuple("_Curve", "p b order Gx Gy G modulus_bits oid context desc openssh") +_ed25519_lib = load_pycryptodome_raw_lib("Cryptodome.PublicKey._ed25519", """ +typedef void Point; +int ed25519_new_point(Point **out, + const uint8_t x[32], + const uint8_t y[32], + size_t modsize, + const void *context); +int ed25519_clone(Point **P, const Point *Q); +void ed25519_free_point(Point *p); +int ed25519_cmp(const Point *p1, const Point *p2); +int ed25519_neg(Point *p); +int ed25519_get_xy(uint8_t *xb, uint8_t *yb, size_t modsize, Point *p); +int ed25519_double(Point *p); +int ed25519_add(Point *P1, const Point *P2); +int ed25519_scalar(Point *P, uint8_t *scalar, size_t scalar_len, uint64_t seed); +""") + +_ed448_lib = load_pycryptodome_raw_lib("Cryptodome.PublicKey._ed448", """ +typedef void EcContext; +typedef void PointEd448; +int ed448_new_context(EcContext **pec_ctx); +void ed448_context(EcContext *ec_ctx); +void ed448_free_context(EcContext *ec_ctx); +int ed448_new_point(PointEd448 **out, + const uint8_t x[56], + const uint8_t y[56], + size_t len, + const EcContext *context); +int ed448_clone(PointEd448 **P, const PointEd448 *Q); +void ed448_free_point(PointEd448 *p); +int ed448_cmp(const PointEd448 *p1, const PointEd448 *p2); +int ed448_neg(PointEd448 *p); +int ed448_get_xy(uint8_t *xb, uint8_t *yb, size_t len, const PointEd448 *p); +int ed448_double(PointEd448 *p); +int ed448_add(PointEd448 *P1, const PointEd448 *P2); +int ed448_scalar(PointEd448 *P, const uint8_t *scalar, size_t scalar_len, uint64_t seed); +""") + + +def lib_func(ecc_obj, func_name): + if ecc_obj._curve.desc == "Ed25519": + result = getattr(_ed25519_lib, "ed25519_" + func_name) + elif ecc_obj._curve.desc == "Ed448": + result = getattr(_ed448_lib, "ed448_" + func_name) + else: + result = getattr(_ec_lib, "ec_ws_" + func_name) + return result + +# +# _curves is a database of curve parameters. Items are indexed by their +# human-friendly name, suchas "P-256". Each item has the following fields: +# - p: the prime number that defines the finite field for all modulo operations +# - b: the constant in the Short Weierstrass curve equation +# - order: the number of elements in the group with the generator below +# - Gx the affine coordinate X of the generator point +# - Gy the affine coordinate Y of the generator point +# - G the generator, as an EccPoint object +# - modulus_bits the minimum number of bits for encoding the modulus p +# - oid an ASCII string with the registered ASN.1 Object ID +# - context a raw pointer to memory holding a context for all curve operations (can be NULL) +# - desc an ASCII string describing the curve +# - openssh the ASCII string used in OpenSSH id files for public keys on this curve +# - name the ASCII string which is also a valid key in _curves + + +_Curve = namedtuple("_Curve", "p b order Gx Gy G modulus_bits oid context desc openssh name") _curves = {} +p192_names = ["p192", "NIST P-192", "P-192", "prime192v1", "secp192r1", + "nistp192"] + + +def init_p192(): + p = 0xfffffffffffffffffffffffffffffffeffffffffffffffff + b = 0x64210519e59c80e70fa7e9ab72243049feb8deecc146b9b1 + order = 0xffffffffffffffffffffffff99def836146bc9b1b4d22831 + Gx = 0x188da80eb03090f67cbf20eb43a18800f4ff0afd82ff1012 + Gy = 0x07192b95ffc8da78631011ed6b24cdd573f977a11e794811 + + p192_modulus = long_to_bytes(p, 24) + p192_b = long_to_bytes(b, 24) + p192_order = long_to_bytes(order, 24) + + ec_p192_context = VoidPointer() + result = _ec_lib.ec_ws_new_context(ec_p192_context.address_of(), + c_uint8_ptr(p192_modulus), + c_uint8_ptr(p192_b), + c_uint8_ptr(p192_order), + c_size_t(len(p192_modulus)), + c_ulonglong(getrandbits(64)) + ) + if result: + raise ImportError("Error %d initializing P-192 context" % result) + + context = SmartPointer(ec_p192_context.get(), _ec_lib.ec_free_context) + p192 = _Curve(Integer(p), + Integer(b), + Integer(order), + Integer(Gx), + Integer(Gy), + None, + 192, + "1.2.840.10045.3.1.1", # ANSI X9.62 / SEC2 + context, + "NIST P-192", + "ecdsa-sha2-nistp192", + "p192") + global p192_names + _curves.update(dict.fromkeys(p192_names, p192)) + + +init_p192() +del init_p192 + + +p224_names = ["p224", "NIST P-224", "P-224", "prime224v1", "secp224r1", + "nistp224"] + + +def init_p224(): + p = 0xffffffffffffffffffffffffffffffff000000000000000000000001 + b = 0xb4050a850c04b3abf54132565044b0b7d7bfd8ba270b39432355ffb4 + order = 0xffffffffffffffffffffffffffff16a2e0b8f03e13dd29455c5c2a3d + Gx = 0xb70e0cbd6bb4bf7f321390b94a03c1d356c21122343280d6115c1d21 + Gy = 0xbd376388b5f723fb4c22dfe6cd4375a05a07476444d5819985007e34 + + p224_modulus = long_to_bytes(p, 28) + p224_b = long_to_bytes(b, 28) + p224_order = long_to_bytes(order, 28) + + ec_p224_context = VoidPointer() + result = _ec_lib.ec_ws_new_context(ec_p224_context.address_of(), + c_uint8_ptr(p224_modulus), + c_uint8_ptr(p224_b), + c_uint8_ptr(p224_order), + c_size_t(len(p224_modulus)), + c_ulonglong(getrandbits(64)) + ) + if result: + raise ImportError("Error %d initializing P-224 context" % result) + + context = SmartPointer(ec_p224_context.get(), _ec_lib.ec_free_context) + p224 = _Curve(Integer(p), + Integer(b), + Integer(order), + Integer(Gx), + Integer(Gy), + None, + 224, + "1.3.132.0.33", # SEC 2 + context, + "NIST P-224", + "ecdsa-sha2-nistp224", + "p224") + global p224_names + _curves.update(dict.fromkeys(p224_names, p224)) + + +init_p224() +del init_p224 + + p256_names = ["p256", "NIST P-256", "P-256", "prime256v1", "secp256r1", "nistp256"] @@ -127,10 +284,11 @@ def init_p256(): Integer(Gy), None, 256, - "1.2.840.10045.3.1.7", # ANSI X9.62 + "1.2.840.10045.3.1.7", # ANSI X9.62 / SEC2 context, "NIST P-256", - "ecdsa-sha2-nistp256") + "ecdsa-sha2-nistp256", + "p256") global p256_names _curves.update(dict.fromkeys(p256_names, p256)) @@ -176,7 +334,8 @@ def init_p384(): "1.3.132.0.34", # SEC 2 context, "NIST P-384", - "ecdsa-sha2-nistp384") + "ecdsa-sha2-nistp384", + "p384") global p384_names _curves.update(dict.fromkeys(p384_names, p384)) @@ -222,7 +381,8 @@ def init_p521(): "1.3.132.0.35", # SEC 2 context, "NIST P-521", - "ecdsa-sha2-nistp521") + "ecdsa-sha2-nistp521", + "p521") global p521_names _curves.update(dict.fromkeys(p521_names, p521)) @@ -231,19 +391,84 @@ init_p521() del init_p521 +ed25519_names = ["ed25519", "Ed25519"] + + +def init_ed25519(): + p = 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffed # 2**255 - 19 + order = 0x1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed + Gx = 0x216936d3cd6e53fec0a4e231fdd6dc5c692cc7609525a7b2c9562d608f25d51a + Gy = 0x6666666666666666666666666666666666666666666666666666666666666658 + + ed25519 = _Curve(Integer(p), + None, + Integer(order), + Integer(Gx), + Integer(Gy), + None, + 255, + "1.3.101.112", # RFC8410 + None, + "Ed25519", # Used throughout; do not change + "ssh-ed25519", + "ed25519") + global ed25519_names + _curves.update(dict.fromkeys(ed25519_names, ed25519)) + + +init_ed25519() +del init_ed25519 + + +ed448_names = ["ed448", "Ed448"] + + +def init_ed448(): + p = 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffeffffffffffffffffffffffffffffffffffffffffffffffffffffffff # 2**448 - 2**224 - 1 + order = 0x3fffffffffffffffffffffffffffffffffffffffffffffffffffffff7cca23e9c44edb49aed63690216cc2728dc58f552378c292ab5844f3 + Gx = 0x4f1970c66bed0ded221d15a622bf36da9e146570470f1767ea6de324a3d3a46412ae1af72ab66511433b80e18b00938e2626a82bc70cc05e + Gy = 0x693f46716eb6bc248876203756c9c7624bea73736ca3984087789c1e05a0c2d73ad3ff1ce67c39c4fdbd132c4ed7c8ad9808795bf230fa14 + + ed448_context = VoidPointer() + result = _ed448_lib.ed448_new_context(ed448_context.address_of()) + if result: + raise ImportError("Error %d initializing Ed448 context" % result) + + context = SmartPointer(ed448_context.get(), _ed448_lib.ed448_free_context) + + ed448 = _Curve(Integer(p), + None, + Integer(order), + Integer(Gx), + Integer(Gy), + None, + 448, + "1.3.101.113", # RFC8410 + context, + "Ed448", # Used throughout; do not change + None, + "ed448") + global ed448_names + _curves.update(dict.fromkeys(ed448_names, ed448)) + + +init_ed448() +del init_ed448 + + class UnsupportedEccFeature(ValueError): pass class EccPoint(object): - """A class to abstract a point over an Elliptic Curve. + """A class to model a point on an Elliptic Curve. - The class support special methods for: + The class supports operators for: * Adding two points: ``R = S + T`` * In-place addition: ``S += T`` * Negating a point: ``R = -T`` - * Comparing two points: ``if S == T: ...`` + * Comparing two points: ``if S == T: ...`` or ``if S != T: ...`` * Multiplying a point by a scalar: ``R = S*k`` * In-place multiplication by a scalar: ``T *= k`` @@ -253,7 +478,7 @@ class EccPoint(object): :ivar y: The affine Y-coordinate of the ECC point :vartype y: integer - :ivar xy: The tuple with X- and Y- coordinates + :ivar xy: The tuple with affine X- and Y- coordinates """ def __init__(self, x, y, curve="p256"): @@ -265,19 +490,26 @@ class EccPoint(object): self._curve_name = curve modulus_bytes = self.size_in_bytes() - context = self._curve.context xb = long_to_bytes(x, modulus_bytes) yb = long_to_bytes(y, modulus_bytes) if len(xb) != modulus_bytes or len(yb) != modulus_bytes: raise ValueError("Incorrect coordinate length") + new_point = lib_func(self, "new_point") + free_func = lib_func(self, "free_point") + self._point = VoidPointer() - result = _ec_lib.ec_ws_new_point(self._point.address_of(), - c_uint8_ptr(xb), - c_uint8_ptr(yb), - c_size_t(modulus_bytes), - context.get()) + try: + context = self._curve.context.get() + except AttributeError: + context = null_pointer + result = new_point(self._point.address_of(), + c_uint8_ptr(xb), + c_uint8_ptr(yb), + c_size_t(modulus_bytes), + context) + if result: if result == 15: raise ValueError("The EC point does not belong to the curve") @@ -285,26 +517,34 @@ class EccPoint(object): # Ensure that object disposal of this Python object will (eventually) # free the memory allocated by the raw library for the EC point - self._point = SmartPointer(self._point.get(), - _ec_lib.ec_free_point) + self._point = SmartPointer(self._point.get(), free_func) def set(self, point): + clone = lib_func(self, "clone") + free_func = lib_func(self, "free_point") + self._point = VoidPointer() - result = _ec_lib.ec_ws_clone(self._point.address_of(), - point._point.get()) + result = clone(self._point.address_of(), + point._point.get()) + if result: raise ValueError("Error %d while cloning an EC point" % result) - self._point = SmartPointer(self._point.get(), - _ec_lib.ec_free_point) + self._point = SmartPointer(self._point.get(), free_func) return self def __eq__(self, point): - return 0 == _ec_lib.ec_ws_cmp(self._point.get(), point._point.get()) + cmp_func = lib_func(self, "cmp") + return 0 == cmp_func(self._point.get(), point._point.get()) + + # Only needed for Python 2 + def __ne__(self, point): + return not self == point def __neg__(self): + neg_func = lib_func(self, "neg") np = self.copy() - result = _ec_lib.ec_ws_neg(np._point.get()) + result = neg_func(np._point.get()) if result: raise ValueError("Error %d while inverting an EC point" % result) return np @@ -315,13 +555,24 @@ class EccPoint(object): np = EccPoint(x, y, self._curve_name) return np + def _is_eddsa(self): + return self._curve.name in ("ed25519", "ed448") + def is_point_at_infinity(self): - """``True`` if this is the point-at-infinity.""" - return self.xy == (0, 0) + """``True`` if this is the *point-at-infinity*.""" + + if self._is_eddsa(): + return self.x == 0 + else: + return self.xy == (0, 0) def point_at_infinity(self): - """Return the point-at-infinity for the curve this point is on.""" - return EccPoint(0, 0, self._curve_name) + """Return the *point-at-infinity* for the curve.""" + + if self._is_eddsa(): + return EccPoint(0, 1, self._curve_name) + else: + return EccPoint(0, 0, self._curve_name) @property def x(self): @@ -336,10 +587,11 @@ class EccPoint(object): modulus_bytes = self.size_in_bytes() xb = bytearray(modulus_bytes) yb = bytearray(modulus_bytes) - result = _ec_lib.ec_ws_get_xy(c_uint8_ptr(xb), - c_uint8_ptr(yb), - c_size_t(modulus_bytes), - self._point.get()) + get_xy = lib_func(self, "get_xy") + result = get_xy(c_uint8_ptr(xb), + c_uint8_ptr(yb), + c_size_t(modulus_bytes), + self._point.get()) if result: raise ValueError("Error %d while encoding an EC point" % result) @@ -356,11 +608,12 @@ class EccPoint(object): def double(self): """Double this point (in-place operation). - :Return: - :class:`EccPoint` : this same object (to enable chaining) + Returns: + This same object (to enable chaining). """ - result = _ec_lib.ec_ws_double(self._point.get()) + double_func = lib_func(self, "double") + result = double_func(self._point.get()) if result: raise ValueError("Error %d while doubling an EC point" % result) return self @@ -368,7 +621,8 @@ class EccPoint(object): def __iadd__(self, point): """Add a second point to this one""" - result = _ec_lib.ec_ws_add(self._point.get(), point._point.get()) + add_func = lib_func(self, "add") + result = add_func(self._point.get(), point._point.get()) if result: if result == 16: raise ValueError("EC points are not on the same curve") @@ -385,13 +639,14 @@ class EccPoint(object): def __imul__(self, scalar): """Multiply this point by a scalar""" + scalar_func = lib_func(self, "scalar") if scalar < 0: raise ValueError("Scalar multiplication is only defined for non-negative integers") sb = long_to_bytes(scalar) - result = _ec_lib.ec_ws_scalar(self._point.get(), - c_uint8_ptr(sb), - c_size_t(len(sb)), - c_ulonglong(getrandbits(64))) + result = scalar_func(self._point.get(), + c_uint8_ptr(sb), + c_size_t(len(sb)), + c_ulonglong(getrandbits(64))) if result: raise ValueError("Error %d during scalar multiplication" % result) return self @@ -408,6 +663,16 @@ class EccPoint(object): # Last piece of initialization +p192_G = EccPoint(_curves['p192'].Gx, _curves['p192'].Gy, "p192") +p192 = _curves['p192']._replace(G=p192_G) +_curves.update(dict.fromkeys(p192_names, p192)) +del p192_G, p192, p192_names + +p224_G = EccPoint(_curves['p224'].Gx, _curves['p224'].Gy, "p224") +p224 = _curves['p224']._replace(G=p224_G) +_curves.update(dict.fromkeys(p224_names, p224)) +del p224_G, p224, p224_names + p256_G = EccPoint(_curves['p256'].Gx, _curves['p256'].Gy, "p256") p256 = _curves['p256']._replace(G=p256_G) _curves.update(dict.fromkeys(p256_names, p256)) @@ -423,20 +688,37 @@ p521 = _curves['p521']._replace(G=p521_G) _curves.update(dict.fromkeys(p521_names, p521)) del p521_G, p521, p521_names +ed25519_G = EccPoint(_curves['Ed25519'].Gx, _curves['Ed25519'].Gy, "Ed25519") +ed25519 = _curves['Ed25519']._replace(G=ed25519_G) +_curves.update(dict.fromkeys(ed25519_names, ed25519)) +del ed25519_G, ed25519, ed25519_names + +ed448_G = EccPoint(_curves['Ed448'].Gx, _curves['Ed448'].Gy, "Ed448") +ed448 = _curves['Ed448']._replace(G=ed448_G) +_curves.update(dict.fromkeys(ed448_names, ed448)) +del ed448_G, ed448, ed448_names + class EccKey(object): r"""Class defining an ECC key. Do not instantiate directly. Use :func:`generate`, :func:`construct` or :func:`import_key` instead. - :ivar curve: The name of the ECC as defined in :numref:`curve_names`. + :ivar curve: The name of the curve as defined in the `ECC table`_. :vartype curve: string - :ivar pointQ: an ECC point representating the public component + :ivar pointQ: an ECC point representating the public component. :vartype pointQ: :class:`EccPoint` - :ivar d: A scalar representating the private component + :ivar d: A scalar that represents the private component + in NIST P curves. It is smaller than the + order of the generator point. :vartype d: integer + + :ivar seed: A seed that representats the private component + in EdDSA curves + (Ed25519, 32 bytes; Ed448, 57 bytes). + :vartype seed: bytes """ def __init__(self, **kwargs): @@ -444,34 +726,79 @@ class EccKey(object): Keywords: curve : string - It must be *"p256"*, *"P-256"*, *"prime256v1"* or *"secp256r1"*. + The name of the curve. d : integer - Only for a private key. It must be in the range ``[1..order-1]``. + Mandatory for a private key one NIST P curves. + It must be in the range ``[1..order-1]``. + seed : bytes + Mandatory for a private key on the Ed25519 (32 bytes) + or Ed448 (57 bytes) curve. point : EccPoint Mandatory for a public key. If provided for a private key, the implementation will NOT check whether it matches ``d``. + + Only one parameter among ``d``, ``seed`` or ``point`` may be used. """ kwargs_ = dict(kwargs) curve_name = kwargs_.pop("curve", None) self._d = kwargs_.pop("d", None) + self._seed = kwargs_.pop("seed", None) self._point = kwargs_.pop("point", None) + if curve_name is None and self._point: + curve_name = self._point._curve_name if kwargs_: raise TypeError("Unknown parameters: " + str(kwargs_)) if curve_name not in _curves: - raise ValueError("Unsupported curve (%s)", curve_name) + raise ValueError("Unsupported curve (%s)" % curve_name) self._curve = _curves[curve_name] + self.curve = curve_name + + count = int(self._d is not None) + int(self._seed is not None) - if self._d is None: + if count == 0: if self._point is None: - raise ValueError("Either private or public ECC component must be specified, not both") - else: + raise ValueError("At lest one between parameters 'point', 'd' or 'seed' must be specified") + return + + if count == 2: + raise ValueError("Parameters d and seed are mutually exclusive") + + # NIST P curves work with d, EdDSA works with seed + + if not self._is_eddsa(): + if self._seed is not None: + raise ValueError("Parameter 'seed' can only be used with Ed25519 or Ed448") self._d = Integer(self._d) if not 1 <= self._d < self._curve.order: - raise ValueError("Invalid ECC private component") - - self.curve = self._curve.desc + raise ValueError("Parameter d must be an integer smaller than the curve order") + else: + if self._d is not None: + raise ValueError("Parameter d can only be used with NIST P curves") + # RFC 8032, 5.1.5 + if self._curve.name == "ed25519": + if len(self._seed) != 32: + raise ValueError("Parameter seed must be 32 bytes long for Ed25519") + seed_hash = SHA512.new(self._seed).digest() # h + self._prefix = seed_hash[32:] + tmp = bytearray(seed_hash[:32]) + tmp[0] &= 0xF8 + tmp[31] = (tmp[31] & 0x7F) | 0x40 + # RFC 8032, 5.2.5 + elif self._curve.name == "ed448": + if len(self._seed) != 57: + raise ValueError("Parameter seed must be 57 bytes long for Ed448") + seed_hash = SHAKE256.new(self._seed).read(114) # h + self._prefix = seed_hash[57:] + tmp = bytearray(seed_hash[:57]) + tmp[0] &= 0xFC + tmp[55] |= 0x80 + tmp[56] = 0 + self._d = Integer.from_bytes(tmp, byteorder='little') + + def _is_eddsa(self): + return self._curve.desc in ("Ed25519", "Ed448") def __eq__(self, other): if other.has_private() != self.has_private(): @@ -481,7 +808,10 @@ class EccKey(object): def __repr__(self): if self.has_private(): - extra = ", d=%d" % int(self._d) + if self._is_eddsa(): + extra = ", seed=%s" % self._seed.hex() + else: + extra = ", d=%d" % int(self._d) else: extra = "" x, y = self.pointQ.xy @@ -492,6 +822,7 @@ class EccKey(object): return self._d is not None + # ECDSA def _sign(self, z, k): assert 0 < k < self._curve.order @@ -506,6 +837,7 @@ class EccKey(object): s = inv_blind_k * (blind * z + blind_d * r) % order return (r, s) + # ECDSA def _verify(self, z, rs): order = self._curve.order sinv = rs[1].inverse(order) @@ -520,6 +852,12 @@ class EccKey(object): return self._d @property + def seed(self): + if not self.has_private(): + raise ValueError("This is not a private ECC key") + return self._seed + + @property def pointQ(self): if self._point is None: self._point = self._curve.G * self._d @@ -534,9 +872,12 @@ class EccKey(object): return EccKey(curve=self._curve.desc, point=self.pointQ) - def _export_subjectPublicKeyInfo(self, compress): + def _export_SEC1(self, compress): + if self._is_eddsa(): + raise ValueError("SEC1 format is unsupported for EdDSA curves") # See 2.2 in RFC5480 and 2.3.3 in SEC1 + # # The first byte is: # - 0x02: compressed, only X-coordinate, Y-coordinate is even # - 0x03: compressed, only X-coordinate, Y-coordinate is odd @@ -547,20 +888,45 @@ class EccKey(object): modulus_bytes = self.pointQ.size_in_bytes() if compress: - first_byte = 2 + self.pointQ.y.is_odd() - public_key = (bchr(first_byte) + + if self.pointQ.y.is_odd(): + first_byte = b'\x03' + else: + first_byte = b'\x02' + public_key = (first_byte + self.pointQ.x.to_bytes(modulus_bytes)) else: public_key = (b'\x04' + self.pointQ.x.to_bytes(modulus_bytes) + self.pointQ.y.to_bytes(modulus_bytes)) + return public_key - unrestricted_oid = "1.2.840.10045.2.1" - return _create_subject_public_key_info(unrestricted_oid, + def _export_eddsa(self): + x, y = self.pointQ.xy + if self._curve.name == "ed25519": + result = bytearray(y.to_bytes(32, byteorder='little')) + result[31] = ((x & 1) << 7) | result[31] + elif self._curve.name == "ed448": + result = bytearray(y.to_bytes(57, byteorder='little')) + result[56] = (x & 1) << 7 + else: + raise ValueError("Not an EdDSA key to export") + return bytes(result) + + def _export_subjectPublicKeyInfo(self, compress): + if self._is_eddsa(): + oid = self._curve.oid + public_key = self._export_eddsa() + params = None + else: + oid = "1.2.840.10045.2.1" # unrestricted + public_key = self._export_SEC1(compress) + params = DerObjectId(self._curve.oid) + + return _create_subject_public_key_info(oid, public_key, - DerObjectId(self._curve.oid)) + params) - def _export_private_der(self, include_ec_params=True): + def _export_rfc5915_private_der(self, include_ec_params=True): assert self.has_private() @@ -593,11 +959,18 @@ class EccKey(object): if kwargs.get('passphrase', None) is not None and 'protection' not in kwargs: raise ValueError("At least the 'protection' parameter should be present") - unrestricted_oid = "1.2.840.10045.2.1" - private_key = self._export_private_der(include_ec_params=False) + if self._is_eddsa(): + oid = self._curve.oid + private_key = DerOctetString(self._seed).encode() + params = None + else: + oid = "1.2.840.10045.2.1" # unrestricted + private_key = self._export_rfc5915_private_der(include_ec_params=False) + params = DerObjectId(self._curve.oid) + result = PKCS8.wrap(private_key, - unrestricted_oid, - key_params=DerObjectId(self._curve.oid), + oid, + key_params=params, **kwargs) return result @@ -610,7 +983,7 @@ class EccKey(object): def _export_private_pem(self, passphrase, **kwargs): from Cryptodome.IO import PEM - encoded_der = self._export_private_der() + encoded_der = self._export_rfc5915_private_der() return PEM.encode(encoded_der, "EC PRIVATE KEY", passphrase, **kwargs) def _export_private_clear_pkcs8_in_clear_pem(self): @@ -633,19 +1006,27 @@ class EccKey(object): raise ValueError("Cannot export OpenSSH private keys") desc = self._curve.openssh - modulus_bytes = self.pointQ.size_in_bytes() - if compress: - first_byte = 2 + self.pointQ.y.is_odd() - public_key = (bchr(first_byte) + - self.pointQ.x.to_bytes(modulus_bytes)) + if desc is None: + raise ValueError("Cannot export %s keys as OpenSSH" % self._curve.name) + elif desc == "ssh-ed25519": + public_key = self._export_eddsa() + comps = (tobytes(desc), tobytes(public_key)) else: - public_key = (b'\x04' + - self.pointQ.x.to_bytes(modulus_bytes) + - self.pointQ.y.to_bytes(modulus_bytes)) + modulus_bytes = self.pointQ.size_in_bytes() + + if compress: + first_byte = 2 + self.pointQ.y.is_odd() + public_key = (bchr(first_byte) + + self.pointQ.x.to_bytes(modulus_bytes)) + else: + public_key = (b'\x04' + + self.pointQ.x.to_bytes(modulus_bytes) + + self.pointQ.y.to_bytes(modulus_bytes)) + + middle = desc.split("-")[2] + comps = (tobytes(desc), tobytes(middle), public_key) - middle = desc.split("-")[2] - comps = (tobytes(desc), tobytes(middle), public_key) blob = b"".join([struct.pack(">I", len(x)) + x for x in comps]) return desc + " " + tostr(binascii.b2a_base64(blob)) @@ -665,6 +1046,15 @@ class EccKey(object): - ``'PEM'``. The key will be encoded in a PEM_ envelope (ASCII). - ``'OpenSSH'``. The key will be encoded in the OpenSSH_ format (ASCII, public keys only). + - ``'SEC1'``. The public key (i.e., the EC point) will be encoded + into ``bytes`` according to Section 2.3.3 of `SEC1`_ + (which is a subset of the older X9.62 ITU standard). + Only for NIST P-curves. + - ``'raw'``. The public key will be encoded as ``bytes``, + without any metadata. + + * For NIST P-curves: equivalent to ``'SEC1'``. + * For EdDSA curves: ``bytes`` in the format defined in `RFC8032`_. passphrase (byte string or string): The passphrase to use for protecting the private key. @@ -673,9 +1063,7 @@ class EccKey(object): Only relevant for private keys. If ``True`` (default and recommended), the `PKCS#8`_ representation - will be used. - - If ``False``, the much weaker `PEM encryption`_ mechanism will be used. + will be used. It must be ``True`` for EdDSA curves. protection (string): When a private key is exported with password-protection @@ -684,10 +1072,13 @@ class EccKey(object): It is recommended to use ``PBKDF2WithHMAC-SHA1AndAES128-CBC``. compress (boolean): - If ``True``, a more compact representation of the public key - with the X-coordinate only is used. + If ``True``, the method returns a more compact representation + of the public key, with the X-coordinate only. + + If ``False`` (default), the method returns the full public key. - If ``False`` (default), the full public key will be exported. + This parameter is ignored for EdDSA curves, as compression is + mandatory. .. warning:: If you don't provide a passphrase, the private key will be @@ -700,18 +1091,18 @@ class EccKey(object): .. _PEM: http://www.ietf.org/rfc/rfc1421.txt .. _`PEM encryption`: http://www.ietf.org/rfc/rfc1423.txt - .. _`PKCS#8`: http://www.ietf.org/rfc/rfc5208.txt .. _OpenSSH: http://www.openssh.com/txt/rfc5656.txt .. _RFC5480: https://tools.ietf.org/html/rfc5480 - .. _RFC5915: http://www.ietf.org/rfc/rfc5915.txt + .. _SEC1: https://www.secg.org/sec1-v2.pdf Returns: - A multi-line string (for PEM and OpenSSH) or bytes (for DER) with the encoded key. + A multi-line string (for ``'PEM'`` and ``'OpenSSH'``) or + ``bytes`` (for ``'DER'``, ``'SEC1'``, and ``'raw'``) with the encoded key. """ args = kwargs.copy() ext_format = args.pop("format") - if ext_format not in ("PEM", "DER", "OpenSSH"): + if ext_format not in ("PEM", "DER", "OpenSSH", "SEC1", "raw"): raise ValueError("Unknown format '%s'" % ext_format) compress = args.pop("compress", False) @@ -723,6 +1114,10 @@ class EccKey(object): if not passphrase: raise ValueError("Empty passphrase") use_pkcs8 = args.pop("use_pkcs8", True) + + if not use_pkcs8 and self._is_eddsa(): + raise ValueError("'pkcs8' must be True for EdDSA curves") + if ext_format == "PEM": if use_pkcs8: if passphrase: @@ -738,9 +1133,10 @@ class EccKey(object): if use_pkcs8: return self._export_pkcs8(passphrase=passphrase, **args) else: - return self._export_private_der() + return self._export_rfc5915_private_der() else: - raise ValueError("Private keys cannot be exported in OpenSSH format") + raise ValueError("Private keys cannot be exported " + "in the '%s' format" % ext_format) else: # Public key if args: raise ValueError("Unexpected parameters: '%s'" % args) @@ -748,6 +1144,13 @@ class EccKey(object): return self._export_public_pem(compress) elif ext_format == "DER": return self._export_subjectPublicKeyInfo(compress) + elif ext_format == "SEC1": + return self._export_SEC1(compress) + elif ext_format == "raw": + if self._curve.name in ('ed25519', 'ed448'): + return self._export_eddsa() + else: + return self._export_SEC1(compress) else: return self._export_openssh(compress) @@ -758,7 +1161,7 @@ def generate(**kwargs): Args: curve (string): - Mandatory. It must be a curve name defined in :numref:`curve_names`. + Mandatory. It must be a curve name defined in the `ECC table`_. randfunc (callable): Optional. The RNG to read randomness from. @@ -771,30 +1174,46 @@ def generate(**kwargs): if kwargs: raise TypeError("Unknown parameters: " + str(kwargs)) - d = Integer.random_range(min_inclusive=1, - max_exclusive=curve.order, - randfunc=randfunc) + if _curves[curve_name].name == "ed25519": + seed = randfunc(32) + new_key = EccKey(curve=curve_name, seed=seed) + elif _curves[curve_name].name == "ed448": + seed = randfunc(57) + new_key = EccKey(curve=curve_name, seed=seed) + else: + d = Integer.random_range(min_inclusive=1, + max_exclusive=curve.order, + randfunc=randfunc) + new_key = EccKey(curve=curve_name, d=d) - return EccKey(curve=curve_name, d=d) + return new_key def construct(**kwargs): """Build a new ECC key (private or public) starting from some base components. - Args: + In most cases, you will already have an existing key + which you can read in with :func:`import_key` instead + of this function. + Args: curve (string): - Mandatory. It must be a curve name defined in :numref:`curve_names`. + Mandatory. The name of the elliptic curve, as defined in the `ECC table`_. d (integer): - Only for a private key. It must be in the range ``[1..order-1]``. + Mandatory for a private key and a NIST P-curve (e.g., P-256): + the integer in the range ``[1..order-1]`` that represents the key. + + seed (bytes): + Mandatory for a private key and an EdDSA curve. + It must be 32 bytes for Ed25519, and 57 bytes for Ed448. point_x (integer): - Mandatory for a public key. X coordinate (affine) of the ECC point. + Mandatory for a public key: the X coordinate (affine) of the ECC point. point_y (integer): - Mandatory for a public key. Y coordinate (affine) of the ECC point. + Mandatory for a public key: the Y coordinate (affine) of the ECC point. Returns: :class:`EccKey` : a new ECC key object @@ -812,29 +1231,39 @@ def construct(**kwargs): # ValueError is raised if the point is not on the curve kwargs["point"] = EccPoint(point_x, point_y, curve_name) + new_key = EccKey(**kwargs) + # Validate that the private key matches the public one - d = kwargs.get("d", None) - if d is not None and "point" in kwargs: - pub_key = curve.G * d + # because EccKey will not do that automatically + if new_key.has_private() and 'point' in kwargs: + pub_key = curve.G * new_key.d if pub_key.xy != (point_x, point_y): raise ValueError("Private and public ECC keys do not match") - return EccKey(**kwargs) + return new_key -def _import_public_der(curve_oid, ec_point): +def _import_public_der(ec_point, curve_oid=None, curve_name=None): """Convert an encoded EC point into an EccKey object + ec_point: byte string with the EC point (SEC1-encoded) + curve_oid: string with the name the curve curve_name: string with the OID of the curve - ec_point: byte string with the EC point (not DER encoded) + + Either curve_id or curve_name must be specified """ - for curve_name, curve in _curves.items(): - if curve.oid == curve_oid: + for _curve_name, curve in _curves.items(): + if curve_oid and curve.oid == curve_oid: + break + if curve_name == _curve_name: break else: - raise UnsupportedEccFeature("Unsupported ECC curve (OID: %s)" % curve_oid) + if curve_oid: + raise UnsupportedEccFeature("Unsupported ECC curve (OID: %s)" % curve_oid) + else: + raise UnsupportedEccFeature("Unsupported ECC curve (%s)" % curve_name) # See 2.2 in RFC5480 and 2.3.3 in SEC1 # The first byte is: @@ -854,11 +1283,12 @@ def _import_public_der(curve_oid, ec_point): x = Integer.from_bytes(ec_point[1:modulus_bytes+1]) y = Integer.from_bytes(ec_point[modulus_bytes+1:]) # Compressed point - elif point_type in (0x02, 0x3): + elif point_type in (0x02, 0x03): if len(ec_point) != (1 + modulus_bytes): raise ValueError("Incorrect EC point length") x = Integer.from_bytes(ec_point[1:]) - y = (x**3 - x*3 + curve.b).sqrt(curve.p) # Short Weierstrass + # Right now, we only support Short Weierstrass curves + y = (x**3 - x*3 + curve.b).sqrt(curve.p) if point_type == 0x02 and y.is_odd(): y = curve.p - y if point_type == 0x03 and y.is_even(): @@ -866,7 +1296,7 @@ def _import_public_der(curve_oid, ec_point): else: raise ValueError("Incorrect EC point encoding") - return construct(curve=curve_name, point_x=x, point_y=y) + return construct(curve=_curve_name, point_x=x, point_y=y) def _import_subjectPublicKeyInfo(encoded, *kwargs): @@ -877,38 +1307,51 @@ def _import_subjectPublicKeyInfo(encoded, *kwargs): # Parse the generic subjectPublicKeyInfo structure oid, ec_point, params = _expand_subject_public_key_info(encoded) - # ec_point must be an encoded OCTET STRING - # params is encoded ECParameters - - # We accept id-ecPublicKey, id-ecDH, id-ecMQV without making any - # distiction for now. - - # Restrictions can be captured in the key usage certificate - # extension - unrestricted_oid = "1.2.840.10045.2.1" - ecdh_oid = "1.3.132.1.12" - ecmqv_oid = "1.3.132.1.13" + nist_p_oids = ( + "1.2.840.10045.2.1", # id-ecPublicKey (unrestricted) + "1.3.132.1.12", # id-ecDH + "1.3.132.1.13" # id-ecMQV + ) + eddsa_oids = { + "1.3.101.112": ("Ed25519", _import_ed25519_public_key), # id-Ed25519 + "1.3.101.113": ("Ed448", _import_ed448_public_key) # id-Ed448 + } + + if oid in nist_p_oids: + # See RFC5480 + + # Parameters are mandatory and encoded as ECParameters + # ECParameters ::= CHOICE { + # namedCurve OBJECT IDENTIFIER + # -- implicitCurve NULL + # -- specifiedCurve SpecifiedECDomain + # } + # implicitCurve and specifiedCurve are not supported (as per RFC) + if not params: + raise ValueError("Missing ECC parameters for ECC OID %s" % oid) + try: + curve_oid = DerObjectId().decode(params).value + except ValueError: + raise ValueError("Error decoding namedCurve") - if oid not in (unrestricted_oid, ecdh_oid, ecmqv_oid): - raise UnsupportedEccFeature("Unsupported ECC purpose (OID: %s)" % oid) + # ECPoint ::= OCTET STRING + return _import_public_der(ec_point, curve_oid=curve_oid) - # Parameters are mandatory for all three types - if not params: - raise ValueError("Missing ECC parameters") + elif oid in eddsa_oids: + # See RFC8410 + curve_name, import_eddsa_public_key = eddsa_oids[oid] - # ECParameters ::= CHOICE { - # namedCurve OBJECT IDENTIFIER - # -- implicitCurve NULL - # -- specifiedCurve SpecifiedECDomain - # } - # - # implicitCurve and specifiedCurve are not supported (as per RFC) - curve_oid = DerObjectId().decode(params).value + # Parameters must be absent + if params: + raise ValueError("Unexpected ECC parameters for ECC OID %s" % oid) - return _import_public_der(curve_oid, ec_point) + x, y = import_eddsa_public_key(ec_point) + return construct(point_x=x, point_y=y, curve=curve_name) + else: + raise UnsupportedEccFeature("Unsupported ECC OID: %s" % oid) -def _import_private_der(encoded, passphrase, curve_oid=None): +def _import_rfc5915_der(encoded, passphrase, curve_oid=None): # See RFC5915 https://tools.ietf.org/html/rfc5915 # @@ -949,7 +1392,7 @@ def _import_private_der(encoded, passphrase, curve_oid=None): # Decode public key (if any) if len(private_key) == 4: public_key_enc = DerBitString(explicit=1).decode(private_key[3]).value - public_key = _import_public_der(curve_oid, public_key_enc) + public_key = _import_public_der(public_key_enc, curve_oid=curve_oid) point_x = public_key.pointQ.x point_y = public_key.pointQ.y else: @@ -961,28 +1404,30 @@ def _import_private_der(encoded, passphrase, curve_oid=None): def _import_pkcs8(encoded, passphrase): from Cryptodome.IO import PKCS8 - # From RFC5915, Section 1: - # - # Distributing an EC private key with PKCS#8 [RFC5208] involves including: - # a) id-ecPublicKey, id-ecDH, or id-ecMQV (from [RFC5480]) with the - # namedCurve as the parameters in the privateKeyAlgorithm field; and - # b) ECPrivateKey in the PrivateKey field, which is an OCTET STRING. - algo_oid, private_key, params = PKCS8.unwrap(encoded, passphrase) - # We accept id-ecPublicKey, id-ecDH, id-ecMQV without making any - # distiction for now. - unrestricted_oid = "1.2.840.10045.2.1" - ecdh_oid = "1.3.132.1.12" - ecmqv_oid = "1.3.132.1.13" - - if algo_oid not in (unrestricted_oid, ecdh_oid, ecmqv_oid): + nist_p_oids = ( + "1.2.840.10045.2.1", # id-ecPublicKey (unrestricted) + "1.3.132.1.12", # id-ecDH + "1.3.132.1.13" # id-ecMQV + ) + eddsa_oids = { + "1.3.101.112": "Ed25519", # id-Ed25519 + "1.3.101.113": "Ed448", # id-Ed448 + } + + if algo_oid in nist_p_oids: + curve_oid = DerObjectId().decode(params).value + return _import_rfc5915_der(private_key, passphrase, curve_oid) + elif algo_oid in eddsa_oids: + if params is not None: + raise ValueError("EdDSA ECC private key must not have parameters") + curve_oid = None + seed = DerOctetString().decode(private_key).payload + return construct(curve=eddsa_oids[algo_oid], seed=seed) + else: raise UnsupportedEccFeature("Unsupported ECC purpose (OID: %s)" % algo_oid) - curve_oid = DerObjectId().decode(params).value - - return _import_private_der(private_key, passphrase, curve_oid) - def _import_x509_cert(encoded, *kwargs): @@ -1007,7 +1452,7 @@ def _import_der(encoded, passphrase): pass try: - return _import_private_der(encoded, passphrase) + return _import_rfc5915_der(encoded, passphrase) except UnsupportedEccFeature as err: raise err except (ValueError, TypeError, IndexError): @@ -1024,22 +1469,49 @@ def _import_der(encoded, passphrase): def _import_openssh_public(encoded): - keystring = binascii.a2b_base64(encoded.split(b' ')[1]) + parts = encoded.split(b' ') + if len(parts) not in (2, 3): + raise ValueError("Not an openssh public key") - keyparts = [] - while len(keystring) > 4: - lk = struct.unpack(">I", keystring[:4])[0] - keyparts.append(keystring[4:4 + lk]) - keystring = keystring[4 + lk:] + try: + keystring = binascii.a2b_base64(parts[1]) + + keyparts = [] + while len(keystring) > 4: + lk = struct.unpack(">I", keystring[:4])[0] + keyparts.append(keystring[4:4 + lk]) + keystring = keystring[4 + lk:] + + if parts[0] != keyparts[0]: + raise ValueError("Mismatch in openssh public key") + + # NIST P curves + if parts[0].startswith(b"ecdsa-sha2-"): + + for curve_name, curve in _curves.items(): + if curve.openssh is None: + continue + if not curve.openssh.startswith("ecdsa-sha2"): + continue + middle = tobytes(curve.openssh.split("-")[2]) + if keyparts[1] == middle: + break + else: + raise ValueError("Unsupported ECC curve: " + middle) - for curve_name, curve in _curves.items(): - middle = tobytes(curve.openssh.split("-")[2]) - if keyparts[1] == middle: - break - else: - raise ValueError("Unsupported ECC curve") + ecc_key = _import_public_der(keyparts[2], curve_oid=curve.oid) - return _import_public_der(curve.oid, keyparts[2]) + # EdDSA + elif parts[0] == b"ssh-ed25519": + x, y = _import_ed25519_public_key(keyparts[1]) + ecc_key = construct(curve="Ed25519", point_x=x, point_y=y) + else: + raise ValueError("Unsupported SSH key type: " + parts[0]) + + except (IndexError, TypeError, binascii.Error): + raise ValueError("Error parsing SSH key type: " + parts[0]) + + return ecc_key def _import_openssh_private_ecc(data, password): @@ -1047,51 +1519,168 @@ def _import_openssh_private_ecc(data, password): from ._openssh import (import_openssh_private_generic, read_bytes, read_string, check_padding) - ssh_name, decrypted = import_openssh_private_generic(data, password) + key_type, decrypted = import_openssh_private_generic(data, password) + + eddsa_keys = { + "ssh-ed25519": ("Ed25519", _import_ed25519_public_key, 32), + } + + # https://datatracker.ietf.org/doc/html/draft-miller-ssh-agent-04 + if key_type.startswith("ecdsa-sha2"): + + ecdsa_curve_name, decrypted = read_string(decrypted) + if ecdsa_curve_name not in _curves: + raise UnsupportedEccFeature("Unsupported ECC curve %s" % ecdsa_curve_name) + curve = _curves[ecdsa_curve_name] + modulus_bytes = (curve.modulus_bits + 7) // 8 + + public_key, decrypted = read_bytes(decrypted) + + if bord(public_key[0]) != 4: + raise ValueError("Only uncompressed OpenSSH EC keys are supported") + if len(public_key) != 2 * modulus_bytes + 1: + raise ValueError("Incorrect public key length") - name, decrypted = read_string(decrypted) - if name not in _curves: - raise UnsupportedEccFeature("Unsupported ECC curve %s" % name) - curve = _curves[name] - modulus_bytes = (curve.modulus_bits + 7) // 8 + point_x = Integer.from_bytes(public_key[1:1+modulus_bytes]) + point_y = Integer.from_bytes(public_key[1+modulus_bytes:]) - public_key, decrypted = read_bytes(decrypted) + private_key, decrypted = read_bytes(decrypted) + d = Integer.from_bytes(private_key) - if bord(public_key[0]) != 4: - raise ValueError("Only uncompressed OpenSSH EC keys are supported") - if len(public_key) != 2 * modulus_bytes + 1: - raise ValueError("Incorrect public key length") + params = {'d': d, 'curve': ecdsa_curve_name} - point_x = Integer.from_bytes(public_key[1:1+modulus_bytes]) - point_y = Integer.from_bytes(public_key[1+modulus_bytes:]) - point = EccPoint(point_x, point_y, curve=name) + elif key_type in eddsa_keys: - private_key, decrypted = read_bytes(decrypted) - d = Integer.from_bytes(private_key) + curve_name, import_eddsa_public_key, seed_len = eddsa_keys[key_type] + + public_key, decrypted = read_bytes(decrypted) + point_x, point_y = import_eddsa_public_key(public_key) + + private_public_key, decrypted = read_bytes(decrypted) + seed = private_public_key[:seed_len] + + params = {'seed': seed, 'curve': curve_name} + else: + raise ValueError("Unsupport SSH agent key type:" + key_type) _, padded = read_string(decrypted) # Comment check_padding(padded) - return EccKey(curve=name, d=d, point=point) + return construct(point_x=point_x, point_y=point_y, **params) + + +def _import_ed25519_public_key(encoded): + """Import an Ed25519 ECC public key, encoded as raw bytes as described + in RFC8032_. + + Args: + encoded (bytes): + The Ed25519 public key to import. It must be 32 bytes long. + + Returns: + :class:`EccKey` : a new ECC key object + + Raises: + ValueError: when the given key cannot be parsed. + + .. _RFC8032: https://datatracker.ietf.org/doc/html/rfc8032 + """ + + if len(encoded) != 32: + raise ValueError("Incorrect length. Only Ed25519 public keys are supported.") + + p = Integer(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffed) # 2**255 - 19 + d = 37095705934669439343138083508754565189542113879843219016388785533085940283555 + + y = bytearray(encoded) + x_lsb = y[31] >> 7 + y[31] &= 0x7F + point_y = Integer.from_bytes(y, byteorder='little') + if point_y >= p: + raise ValueError("Invalid Ed25519 key (y)") + if point_y == 1: + return 0, 1 + u = (point_y**2 - 1) % p + v = ((point_y**2 % p) * d + 1) % p + try: + v_inv = v.inverse(p) + x2 = (u * v_inv) % p + point_x = Integer._tonelli_shanks(x2, p) + if (point_x & 1) != x_lsb: + point_x = p - point_x + except ValueError: + raise ValueError("Invalid Ed25519 public key") + return point_x, point_y + + +def _import_ed448_public_key(encoded): + """Import an Ed448 ECC public key, encoded as raw bytes as described + in RFC8032_. + + Args: + encoded (bytes): + The Ed448 public key to import. It must be 57 bytes long. + + Returns: + :class:`EccKey` : a new ECC key object + + Raises: + ValueError: when the given key cannot be parsed. + + .. _RFC8032: https://datatracker.ietf.org/doc/html/rfc8032 + """ -def import_key(encoded, passphrase=None): + if len(encoded) != 57: + raise ValueError("Incorrect length. Only Ed448 public keys are supported.") + + p = Integer(0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffeffffffffffffffffffffffffffffffffffffffffffffffffffffffff) # 2**448 - 2**224 - 1 + d = 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffeffffffffffffffffffffffffffffffffffffffffffffffffffff6756 + + y = encoded[:56] + x_lsb = bord(encoded[56]) >> 7 + point_y = Integer.from_bytes(y, byteorder='little') + if point_y >= p: + raise ValueError("Invalid Ed448 key (y)") + if point_y == 1: + return 0, 1 + + u = (point_y**2 - 1) % p + v = ((point_y**2 % p) * d - 1) % p + try: + v_inv = v.inverse(p) + x2 = (u * v_inv) % p + point_x = Integer._tonelli_shanks(x2, p) + if (point_x & 1) != x_lsb: + point_x = p - point_x + except ValueError: + raise ValueError("Invalid Ed448 public key") + return point_x, point_y + + +def import_key(encoded, passphrase=None, curve_name=None): """Import an ECC key (public or private). Args: encoded (bytes or multi-line string): The ECC key to import. + The function will try to automatically detect the right format. - An ECC **public** key can be: + Supported formats for an ECC **public** key: - - An X.509 certificate, binary (DER) or ASCII (PEM) - - An X.509 ``subjectPublicKeyInfo``, binary (DER) or ASCII (PEM) - - An OpenSSH line (e.g. the content of ``~/.ssh/id_ecdsa``, ASCII) + * X.509 certificate: binary (DER) or ASCII (PEM). + * X.509 ``subjectPublicKeyInfo``: binary (DER) or ASCII (PEM). + * SEC1_ (or X9.62), as ``bytes``. NIST P curves only. + You must also provide the ``curve_name`` (with a value from the `ECC table`_) + * OpenSSH line, defined in RFC5656_ and RFC8709_ (ASCII). + This is normally the content of files like ``~/.ssh/id_ecdsa.pub``. - An ECC **private** key can be: + Supported formats for an ECC **private** key: - - In binary format (DER, see section 3 of `RFC5915`_ or `PKCS#8`_) - - In ASCII format (PEM or `OpenSSH 6.5+`_) + * A binary ``ECPrivateKey`` structure, as defined in `RFC5915`_ (DER). + NIST P curves only. + * A `PKCS#8`_ structure (or the more recent Asymmetric Key Package, RFC5958_): binary (DER) or ASCII (PEM). + * `OpenSSH 6.5`_ and newer versions (ASCII). Private keys can be in the clear or password-protected. @@ -1099,9 +1688,21 @@ def import_key(encoded, passphrase=None): passphrase (byte string): The passphrase to use for decrypting a private key. - Encryption may be applied protected at the PEM level or at the PKCS#8 level. + Encryption may be applied protected at the PEM level (not recommended) + or at the PKCS#8 level (recommended). This parameter is ignored if the key in input is not encrypted. + curve_name (string): + For a SEC1 encoding only. This is the name of the curve, + as defined in the `ECC table`_. + + .. note:: + + To import EdDSA private and public keys, when encoded as raw ``bytes``, use: + + * :func:`Cryptodome.Signature.eddsa.import_public_key`, or + * :func:`Cryptodome.Signature.eddsa.import_private_key`. + Returns: :class:`EccKey` : a new ECC key object @@ -1109,11 +1710,15 @@ def import_key(encoded, passphrase=None): ValueError: when the given key cannot be parsed (possibly because the pass phrase is wrong). - .. _RFC1421: http://www.ietf.org/rfc/rfc1421.txt - .. _RFC1423: http://www.ietf.org/rfc/rfc1423.txt - .. _RFC5915: http://www.ietf.org/rfc/rfc5915.txt - .. _`PKCS#8`: http://www.ietf.org/rfc/rfc5208.txt - .. _`OpenSSH 6.5+`: https://flak.tedunangst.com/post/new-openssh-key-format-and-bcrypt-pbkdf + .. _RFC1421: https://datatracker.ietf.org/doc/html/rfc1421 + .. _RFC1423: https://datatracker.ietf.org/doc/html/rfc1423 + .. _RFC5915: https://datatracker.ietf.org/doc/html/rfc5915 + .. _RFC5656: https://datatracker.ietf.org/doc/html/rfc5656 + .. _RFC8709: https://datatracker.ietf.org/doc/html/rfc8709 + .. _RFC5958: https://datatracker.ietf.org/doc/html/rfc5958 + .. _`PKCS#8`: https://datatracker.ietf.org/doc/html/rfc5208 + .. _`OpenSSH 6.5`: https://flak.tedunangst.com/post/new-openssh-key-format-and-bcrypt-pbkdf + .. _SEC1: https://www.secg.org/sec1-v2.pdf """ from Cryptodome.IO import PEM @@ -1135,12 +1740,11 @@ def import_key(encoded, passphrase=None): # Remove any EC PARAMETERS section # Ignore its content because the curve type must be already given in the key - if sys.version_info[:2] != (2, 6): - ecparams_start = "-----BEGIN EC PARAMETERS-----" - ecparams_end = "-----END EC PARAMETERS-----" - text_encoded = re.sub(ecparams_start + ".*?" + ecparams_end, "", - text_encoded, - flags=re.DOTALL) + ecparams_start = "-----BEGIN EC PARAMETERS-----" + ecparams_end = "-----END EC PARAMETERS-----" + text_encoded = re.sub(ecparams_start + ".*?" + ecparams_end, "", + text_encoded, + flags=re.DOTALL) der_encoded, marker, enc_flag = PEM.decode(text_encoded, passphrase) if enc_flag: @@ -1154,13 +1758,19 @@ def import_key(encoded, passphrase=None): return result # OpenSSH - if encoded.startswith(b'ecdsa-sha2-'): + if encoded.startswith((b'ecdsa-sha2-', b'ssh-ed25519')): return _import_openssh_public(encoded) # DER if len(encoded) > 0 and bord(encoded[0]) == 0x30: return _import_der(encoded, passphrase) + # SEC1 + if len(encoded) > 0 and bord(encoded[0]) in b'\x02\x03\x04': + if curve_name is None: + raise ValueError("No curve name was provided") + return _import_public_der(encoded, curve_name=curve_name) + raise ValueError("ECC key format is not supported") |