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|
| import re
|
| import struct
|
| from functools import reduce
|
|
|
| from Cryptodome.Util.py3compat import (tobytes, bord, _copy_bytes, iter_range,
|
| tostr, bchr, bstr)
|
|
|
| from Cryptodome.Hash import SHA1, SHA256, HMAC, CMAC, BLAKE2s
|
| from Cryptodome.Util.strxor import strxor
|
| from Cryptodome.Random import get_random_bytes
|
| from Cryptodome.Util.number import size as bit_size, long_to_bytes, bytes_to_long
|
|
|
| from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib,
|
| create_string_buffer,
|
| get_raw_buffer, c_size_t)
|
|
|
| _raw_salsa20_lib = load_pycryptodome_raw_lib(
|
| "Cryptodome.Cipher._Salsa20",
|
| """
|
| int Salsa20_8_core(const uint8_t *x, const uint8_t *y,
|
| uint8_t *out);
|
| """)
|
|
|
| _raw_scrypt_lib = load_pycryptodome_raw_lib(
|
| "Cryptodome.Protocol._scrypt",
|
| """
|
| typedef int (core_t)(const uint8_t [64], const uint8_t [64], uint8_t [64]);
|
| int scryptROMix(const uint8_t *data_in, uint8_t *data_out,
|
| size_t data_len, unsigned N, core_t *core);
|
| """)
|
|
|
|
|
| def PBKDF1(password, salt, dkLen, count=1000, hashAlgo=None):
|
| """Derive one key from a password (or passphrase).
|
|
|
| This function performs key derivation according to an old version of
|
| the PKCS#5 standard (v1.5) or `RFC2898
|
| <https://www.ietf.org/rfc/rfc2898.txt>`_.
|
|
|
| Args:
|
| password (string):
|
| The secret password to generate the key from.
|
| salt (byte string):
|
| An 8 byte string to use for better protection from dictionary attacks.
|
| This value does not need to be kept secret, but it should be randomly
|
| chosen for each derivation.
|
| dkLen (integer):
|
| The length of the desired key. The default is 16 bytes, suitable for
|
| instance for :mod:`Cryptodome.Cipher.AES`.
|
| count (integer):
|
| The number of iterations to carry out. The recommendation is 1000 or
|
| more.
|
| hashAlgo (module):
|
| The hash algorithm to use, as a module or an object from the :mod:`Cryptodome.Hash` package.
|
| The digest length must be no shorter than ``dkLen``.
|
| The default algorithm is :mod:`Cryptodome.Hash.SHA1`.
|
|
|
| Return:
|
| A byte string of length ``dkLen`` that can be used as key.
|
| """
|
|
|
| if not hashAlgo:
|
| hashAlgo = SHA1
|
| password = tobytes(password)
|
| pHash = hashAlgo.new(password+salt)
|
| digest = pHash.digest_size
|
| if dkLen > digest:
|
| raise TypeError("Selected hash algorithm has a too short digest (%d bytes)." % digest)
|
| if len(salt) != 8:
|
| raise ValueError("Salt is not 8 bytes long (%d bytes instead)." % len(salt))
|
| for i in iter_range(count-1):
|
| pHash = pHash.new(pHash.digest())
|
| return pHash.digest()[:dkLen]
|
|
|
|
|
| def PBKDF2(password, salt, dkLen=16, count=1000, prf=None, hmac_hash_module=None):
|
| """Derive one or more keys from a password (or passphrase).
|
|
|
| This function performs key derivation according to the PKCS#5 standard (v2.0).
|
|
|
| Args:
|
| password (string or byte string):
|
| The secret password to generate the key from.
|
|
|
| Strings will be encoded as ISO 8859-1 (also known as Latin-1),
|
| which does not allow any characters with codepoints > 255.
|
| salt (string or byte string):
|
| A (byte) string to use for better protection from dictionary attacks.
|
| This value does not need to be kept secret, but it should be randomly
|
| chosen for each derivation. It is recommended to use at least 16 bytes.
|
|
|
| Strings will be encoded as ISO 8859-1 (also known as Latin-1),
|
| which does not allow any characters with codepoints > 255.
|
| dkLen (integer):
|
| The cumulative length of the keys to produce.
|
|
|
| Due to a flaw in the PBKDF2 design, you should not request more bytes
|
| than the ``prf`` can output. For instance, ``dkLen`` should not exceed
|
| 20 bytes in combination with ``HMAC-SHA1``.
|
| count (integer):
|
| The number of iterations to carry out. The higher the value, the slower
|
| and the more secure the function becomes.
|
|
|
| You should find the maximum number of iterations that keeps the
|
| key derivation still acceptable on the slowest hardware you must support.
|
|
|
| Although the default value is 1000, **it is recommended to use at least
|
| 1000000 (1 million) iterations**.
|
| prf (callable):
|
| A pseudorandom function. It must be a function that returns a
|
| pseudorandom byte string from two parameters: a secret and a salt.
|
| The slower the algorithm, the more secure the derivation function.
|
| If not specified, **HMAC-SHA1** is used.
|
| hmac_hash_module (module):
|
| A module from ``Cryptodome.Hash`` implementing a Merkle-Damgard cryptographic
|
| hash, which PBKDF2 must use in combination with HMAC.
|
| This parameter is mutually exclusive with ``prf``.
|
|
|
| Return:
|
| A byte string of length ``dkLen`` that can be used as key material.
|
| If you want multiple keys, just break up this string into segments of the desired length.
|
| """
|
|
|
| password = tobytes(password)
|
| salt = tobytes(salt)
|
|
|
| if prf and hmac_hash_module:
|
| raise ValueError("'prf' and 'hmac_hash_module' are mutually exlusive")
|
|
|
| if prf is None and hmac_hash_module is None:
|
| hmac_hash_module = SHA1
|
|
|
| if prf or not hasattr(hmac_hash_module, "_pbkdf2_hmac_assist"):
|
|
|
|
|
| if prf is None:
|
| prf = lambda p, s: HMAC.new(p, s, hmac_hash_module).digest()
|
|
|
| def link(s):
|
| s[0], s[1] = s[1], prf(password, s[1])
|
| return s[0]
|
|
|
| key = b''
|
| i = 1
|
| while len(key) < dkLen:
|
| s = [prf(password, salt + struct.pack(">I", i))] * 2
|
| key += reduce(strxor, (link(s) for j in range(count)))
|
| i += 1
|
|
|
| else:
|
|
|
| key = b''
|
| i = 1
|
| while len(key) < dkLen:
|
| base = HMAC.new(password, b"", hmac_hash_module)
|
| first_digest = base.copy().update(salt + struct.pack(">I", i)).digest()
|
| key += base._pbkdf2_hmac_assist(first_digest, count)
|
| i += 1
|
|
|
| return key[:dkLen]
|
|
|
|
|
| class _S2V(object):
|
| """String-to-vector PRF as defined in `RFC5297`_.
|
|
|
| This class implements a pseudorandom function family
|
| based on CMAC that takes as input a vector of strings.
|
|
|
| .. _RFC5297: http://tools.ietf.org/html/rfc5297
|
| """
|
|
|
| def __init__(self, key, ciphermod, cipher_params=None):
|
| """Initialize the S2V PRF.
|
|
|
| :Parameters:
|
| key : byte string
|
| A secret that can be used as key for CMACs
|
| based on ciphers from ``ciphermod``.
|
| ciphermod : module
|
| A block cipher module from `Cryptodome.Cipher`.
|
| cipher_params : dictionary
|
| A set of extra parameters to use to create a cipher instance.
|
| """
|
|
|
| self._key = _copy_bytes(None, None, key)
|
| self._ciphermod = ciphermod
|
| self._last_string = self._cache = b'\x00' * ciphermod.block_size
|
|
|
|
|
| self._n_updates = ciphermod.block_size * 8 - 1
|
|
|
| if cipher_params is None:
|
| self._cipher_params = {}
|
| else:
|
| self._cipher_params = dict(cipher_params)
|
|
|
| @staticmethod
|
| def new(key, ciphermod):
|
| """Create a new S2V PRF.
|
|
|
| :Parameters:
|
| key : byte string
|
| A secret that can be used as key for CMACs
|
| based on ciphers from ``ciphermod``.
|
| ciphermod : module
|
| A block cipher module from `Cryptodome.Cipher`.
|
| """
|
| return _S2V(key, ciphermod)
|
|
|
| def _double(self, bs):
|
| doubled = bytes_to_long(bs) << 1
|
| if bord(bs[0]) & 0x80:
|
| doubled ^= 0x87
|
| return long_to_bytes(doubled, len(bs))[-len(bs):]
|
|
|
| def update(self, item):
|
| """Pass the next component of the vector.
|
|
|
| The maximum number of components you can pass is equal to the block
|
| length of the cipher (in bits) minus 1.
|
|
|
| :Parameters:
|
| item : byte string
|
| The next component of the vector.
|
| :Raise TypeError: when the limit on the number of components has been reached.
|
| """
|
|
|
| if self._n_updates == 0:
|
| raise TypeError("Too many components passed to S2V")
|
| self._n_updates -= 1
|
|
|
| mac = CMAC.new(self._key,
|
| msg=self._last_string,
|
| ciphermod=self._ciphermod,
|
| cipher_params=self._cipher_params)
|
| self._cache = strxor(self._double(self._cache), mac.digest())
|
| self._last_string = _copy_bytes(None, None, item)
|
|
|
| def derive(self):
|
| """"Derive a secret from the vector of components.
|
|
|
| :Return: a byte string, as long as the block length of the cipher.
|
| """
|
|
|
| if len(self._last_string) >= 16:
|
|
|
| final = self._last_string[:-16] + strxor(self._last_string[-16:], self._cache)
|
| else:
|
|
|
| padded = (self._last_string + b'\x80' + b'\x00' * 15)[:16]
|
| final = strxor(padded, self._double(self._cache))
|
| mac = CMAC.new(self._key,
|
| msg=final,
|
| ciphermod=self._ciphermod,
|
| cipher_params=self._cipher_params)
|
| return mac.digest()
|
|
|
|
|
| def _HKDF_extract(salt, ikm, hashmod):
|
| prk = HMAC.new(salt, ikm, digestmod=hashmod).digest()
|
| return prk
|
|
|
|
|
| def _HKDF_expand(prk, info, L, hashmod):
|
| t = [b""]
|
| n = 1
|
| tlen = 0
|
| while tlen < L:
|
| hmac = HMAC.new(prk, t[-1] + info + struct.pack('B', n), digestmod=hashmod)
|
| t.append(hmac.digest())
|
| tlen += hashmod.digest_size
|
| n += 1
|
| okm = b"".join(t)
|
| return okm[:L]
|
|
|
|
|
| def HKDF(master, key_len, salt, hashmod, num_keys=1, context=None):
|
| """Derive one or more keys from a master secret using
|
| the HMAC-based KDF defined in RFC5869_.
|
|
|
| Args:
|
| master (byte string):
|
| The unguessable value used by the KDF to generate the other keys.
|
| It must be a high-entropy secret, though not necessarily uniform.
|
| It must not be a password.
|
| key_len (integer):
|
| The length in bytes of every derived key.
|
| salt (byte string):
|
| A non-secret, reusable value that strengthens the randomness
|
| extraction step.
|
| Ideally, it is as long as the digest size of the chosen hash.
|
| If empty, a string of zeroes in used.
|
| hashmod (module):
|
| A cryptographic hash algorithm from :mod:`Cryptodome.Hash`.
|
| :mod:`Cryptodome.Hash.SHA512` is a good choice.
|
| num_keys (integer):
|
| The number of keys to derive. Every key is :data:`key_len` bytes long.
|
| The maximum cumulative length of all keys is
|
| 255 times the digest size.
|
| context (byte string):
|
| Optional identifier describing what the keys are used for.
|
|
|
| Return:
|
| A byte string or a tuple of byte strings.
|
|
|
| .. _RFC5869: http://tools.ietf.org/html/rfc5869
|
| """
|
|
|
| output_len = key_len * num_keys
|
| if output_len > (255 * hashmod.digest_size):
|
| raise ValueError("Too much secret data to derive")
|
| if not salt:
|
| salt = b'\x00' * hashmod.digest_size
|
| if context is None:
|
| context = b""
|
|
|
| prk = _HKDF_extract(salt, master, hashmod)
|
| okm = _HKDF_expand(prk, context, output_len, hashmod)
|
|
|
| if num_keys == 1:
|
| return okm[:key_len]
|
| kol = [okm[idx:idx + key_len]
|
| for idx in iter_range(0, output_len, key_len)]
|
| return list(kol[:num_keys])
|
|
|
|
|
| def scrypt(password, salt, key_len, N, r, p, num_keys=1):
|
| """Derive one or more keys from a passphrase.
|
|
|
| Args:
|
| password (string):
|
| The secret pass phrase to generate the keys from.
|
| salt (string):
|
| A string to use for better protection from dictionary attacks.
|
| This value does not need to be kept secret,
|
| but it should be randomly chosen for each derivation.
|
| It is recommended to be at least 16 bytes long.
|
| key_len (integer):
|
| The length in bytes of each derived key.
|
| N (integer):
|
| CPU/Memory cost parameter. It must be a power of 2 and less
|
| than :math:`2^{32}`.
|
| r (integer):
|
| Block size parameter.
|
| p (integer):
|
| Parallelization parameter.
|
| It must be no greater than :math:`(2^{32}-1)/(4r)`.
|
| num_keys (integer):
|
| The number of keys to derive. Every key is :data:`key_len` bytes long.
|
| By default, only 1 key is generated.
|
| The maximum cumulative length of all keys is :math:`(2^{32}-1)*32`
|
| (that is, 128TB).
|
|
|
| A good choice of parameters *(N, r , p)* was suggested
|
| by Colin Percival in his `presentation in 2009`__:
|
|
|
| - *( 2¹⁴, 8, 1 )* for interactive logins (≤100ms)
|
| - *( 2²⁰, 8, 1 )* for file encryption (≤5s)
|
|
|
| Return:
|
| A byte string or a tuple of byte strings.
|
|
|
| .. __: http://www.tarsnap.com/scrypt/scrypt-slides.pdf
|
| """
|
|
|
| if 2 ** (bit_size(N) - 1) != N:
|
| raise ValueError("N must be a power of 2")
|
| if N >= 2 ** 32:
|
| raise ValueError("N is too big")
|
| if p > ((2 ** 32 - 1) * 32) // (128 * r):
|
| raise ValueError("p or r are too big")
|
|
|
| prf_hmac_sha256 = lambda p, s: HMAC.new(p, s, SHA256).digest()
|
|
|
| stage_1 = PBKDF2(password, salt, p * 128 * r, 1, prf=prf_hmac_sha256)
|
|
|
| scryptROMix = _raw_scrypt_lib.scryptROMix
|
| core = _raw_salsa20_lib.Salsa20_8_core
|
|
|
|
|
| data_out = []
|
| for flow in iter_range(p):
|
| idx = flow * 128 * r
|
| buffer_out = create_string_buffer(128 * r)
|
| result = scryptROMix(stage_1[idx: idx + 128 * r],
|
| buffer_out,
|
| c_size_t(128 * r),
|
| N,
|
| core)
|
| if result:
|
| raise ValueError("Error %X while running scrypt" % result)
|
| data_out += [get_raw_buffer(buffer_out)]
|
|
|
| dk = PBKDF2(password,
|
| b"".join(data_out),
|
| key_len * num_keys, 1,
|
| prf=prf_hmac_sha256)
|
|
|
| if num_keys == 1:
|
| return dk
|
|
|
| kol = [dk[idx:idx + key_len]
|
| for idx in iter_range(0, key_len * num_keys, key_len)]
|
| return kol
|
|
|
|
|
| def _bcrypt_encode(data):
|
| s = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
|
|
|
| bits = []
|
| for c in data:
|
| bits_c = bin(bord(c))[2:].zfill(8)
|
| bits.append(bstr(bits_c))
|
| bits = b"".join(bits)
|
|
|
| bits6 = [bits[idx:idx+6] for idx in range(0, len(bits), 6)]
|
|
|
| result = []
|
| for g in bits6[:-1]:
|
| idx = int(g, 2)
|
| result.append(s[idx])
|
|
|
| g = bits6[-1]
|
| idx = int(g, 2) << (6 - len(g))
|
| result.append(s[idx])
|
| result = "".join(result)
|
|
|
| return tobytes(result)
|
|
|
|
|
| def _bcrypt_decode(data):
|
| s = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
|
|
|
| bits = []
|
| for c in tostr(data):
|
| idx = s.find(c)
|
| bits6 = bin(idx)[2:].zfill(6)
|
| bits.append(bits6)
|
| bits = "".join(bits)
|
|
|
| modulo4 = len(data) % 4
|
| if modulo4 == 1:
|
| raise ValueError("Incorrect length")
|
| elif modulo4 == 2:
|
| bits = bits[:-4]
|
| elif modulo4 == 3:
|
| bits = bits[:-2]
|
|
|
| bits8 = [bits[idx:idx+8] for idx in range(0, len(bits), 8)]
|
|
|
| result = []
|
| for g in bits8:
|
| result.append(bchr(int(g, 2)))
|
| result = b"".join(result)
|
|
|
| return result
|
|
|
|
|
| def _bcrypt_hash(password, cost, salt, constant, invert):
|
| from Cryptodome.Cipher import _EKSBlowfish
|
|
|
| if len(password) > 72:
|
| raise ValueError("The password is too long. It must be 72 bytes at most.")
|
|
|
| if not (4 <= cost <= 31):
|
| raise ValueError("bcrypt cost factor must be in the range 4..31")
|
|
|
| cipher = _EKSBlowfish.new(password, _EKSBlowfish.MODE_ECB, salt, cost, invert)
|
| ctext = constant
|
| for _ in range(64):
|
| ctext = cipher.encrypt(ctext)
|
| return ctext
|
|
|
|
|
| def bcrypt(password, cost, salt=None):
|
| """Hash a password into a key, using the OpenBSD bcrypt protocol.
|
|
|
| Args:
|
| password (byte string or string):
|
| The secret password or pass phrase.
|
| It must be at most 72 bytes long.
|
| It must not contain the zero byte.
|
| Unicode strings will be encoded as UTF-8.
|
| cost (integer):
|
| The exponential factor that makes it slower to compute the hash.
|
| It must be in the range 4 to 31.
|
| A value of at least 12 is recommended.
|
| salt (byte string):
|
| Optional. Random byte string to thwarts dictionary and rainbow table
|
| attacks. It must be 16 bytes long.
|
| If not passed, a random value is generated.
|
|
|
| Return (byte string):
|
| The bcrypt hash
|
|
|
| Raises:
|
| ValueError: if password is longer than 72 bytes or if it contains the zero byte
|
|
|
| """
|
|
|
| password = tobytes(password, "utf-8")
|
|
|
| if password.find(bchr(0)[0]) != -1:
|
| raise ValueError("The password contains the zero byte")
|
|
|
| if len(password) < 72:
|
| password += b"\x00"
|
|
|
| if salt is None:
|
| salt = get_random_bytes(16)
|
| if len(salt) != 16:
|
| raise ValueError("bcrypt salt must be 16 bytes long")
|
|
|
| ctext = _bcrypt_hash(password, cost, salt, b"OrpheanBeholderScryDoubt", True)
|
|
|
| cost_enc = b"$" + bstr(str(cost).zfill(2))
|
| salt_enc = b"$" + _bcrypt_encode(salt)
|
| hash_enc = _bcrypt_encode(ctext[:-1])
|
| return b"$2a" + cost_enc + salt_enc + hash_enc
|
|
|
|
|
| def bcrypt_check(password, bcrypt_hash):
|
| """Verify if the provided password matches the given bcrypt hash.
|
|
|
| Args:
|
| password (byte string or string):
|
| The secret password or pass phrase to test.
|
| It must be at most 72 bytes long.
|
| It must not contain the zero byte.
|
| Unicode strings will be encoded as UTF-8.
|
| bcrypt_hash (byte string, bytearray):
|
| The reference bcrypt hash the password needs to be checked against.
|
|
|
| Raises:
|
| ValueError: if the password does not match
|
| """
|
|
|
| bcrypt_hash = tobytes(bcrypt_hash)
|
|
|
| if len(bcrypt_hash) != 60:
|
| raise ValueError("Incorrect length of the bcrypt hash: %d bytes instead of 60" % len(bcrypt_hash))
|
|
|
| if bcrypt_hash[:4] != b'$2a$':
|
| raise ValueError("Unsupported prefix")
|
|
|
| p = re.compile(br'\$2a\$([0-9][0-9])\$([A-Za-z0-9./]{22,22})([A-Za-z0-9./]{31,31})')
|
| r = p.match(bcrypt_hash)
|
| if not r:
|
| raise ValueError("Incorrect bcrypt hash format")
|
|
|
| cost = int(r.group(1))
|
| if not (4 <= cost <= 31):
|
| raise ValueError("Incorrect cost")
|
|
|
| salt = _bcrypt_decode(r.group(2))
|
|
|
| bcrypt_hash2 = bcrypt(password, cost, salt)
|
|
|
| secret = get_random_bytes(16)
|
|
|
| mac1 = BLAKE2s.new(digest_bits=160, key=secret, data=bcrypt_hash).digest()
|
| mac2 = BLAKE2s.new(digest_bits=160, key=secret, data=bcrypt_hash2).digest()
|
| if mac1 != mac2:
|
| raise ValueError("Incorrect bcrypt hash")
|
|
|
|
|
| def SP800_108_Counter(master, key_len, prf, num_keys=None, label=b'', context=b''):
|
| """Derive one or more keys from a master secret using
|
| a pseudorandom function in Counter Mode, as specified in
|
| `NIST SP 800-108r1 <https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-108r1.pdf>`_.
|
|
|
| Args:
|
| master (byte string):
|
| The secret value used by the KDF to derive the other keys.
|
| It must not be a password.
|
| The length on the secret must be consistent with the input expected by
|
| the :data:`prf` function.
|
| key_len (integer):
|
| The length in bytes of each derived key.
|
| prf (function):
|
| A pseudorandom function that takes two byte strings as parameters:
|
| the secret and an input. It returns another byte string.
|
| num_keys (integer):
|
| The number of keys to derive. Every key is :data:`key_len` bytes long.
|
| By default, only 1 key is derived.
|
| label (byte string):
|
| Optional description of the purpose of the derived keys.
|
| It must not contain zero bytes.
|
| context (byte string):
|
| Optional information pertaining to
|
| the protocol that uses the keys, such as the identity of the
|
| participants, nonces, session IDs, etc.
|
| It must not contain zero bytes.
|
|
|
| Return:
|
| - a byte string (if ``num_keys`` is not specified), or
|
| - a tuple of byte strings (if ``num_key`` is specified).
|
| """
|
|
|
| if num_keys is None:
|
| num_keys = 1
|
|
|
| if context.find(b'\x00') != -1:
|
| raise ValueError("Null byte found in context")
|
|
|
| key_len_enc = long_to_bytes(key_len * num_keys * 8, 4)
|
| output_len = key_len * num_keys
|
|
|
| i = 1
|
| dk = b""
|
| while len(dk) < output_len:
|
| info = long_to_bytes(i, 4) + label + b'\x00' + context + key_len_enc
|
| dk += prf(master, info)
|
| i += 1
|
| if i > 0xFFFFFFFF:
|
| raise ValueError("Overflow in SP800 108 counter")
|
|
|
| if num_keys == 1:
|
| return dk[:key_len]
|
| else:
|
| kol = [dk[idx:idx + key_len]
|
| for idx in iter_range(0, output_len, key_len)]
|
| return kol
|
|
|
