diff options
Diffstat (limited to 'frozen_deps/Cryptodome/Cipher/PKCS1_OAEP.py')
| -rw-r--r-- | frozen_deps/Cryptodome/Cipher/PKCS1_OAEP.py | 44 |
1 files changed, 18 insertions, 26 deletions
diff --git a/frozen_deps/Cryptodome/Cipher/PKCS1_OAEP.py b/frozen_deps/Cryptodome/Cipher/PKCS1_OAEP.py index 7525c5d..08f9efe 100644 --- a/frozen_deps/Cryptodome/Cipher/PKCS1_OAEP.py +++ b/frozen_deps/Cryptodome/Cipher/PKCS1_OAEP.py @@ -23,11 +23,13 @@ from Cryptodome.Signature.pss import MGF1 import Cryptodome.Hash.SHA1 -from Cryptodome.Util.py3compat import bord, _copy_bytes +from Cryptodome.Util.py3compat import _copy_bytes import Cryptodome.Util.number -from Cryptodome.Util.number import ceil_div, bytes_to_long, long_to_bytes -from Cryptodome.Util.strxor import strxor +from Cryptodome.Util.number import ceil_div, bytes_to_long, long_to_bytes +from Cryptodome.Util.strxor import strxor from Cryptodome import Random +from ._pkcs1_oaep_decode import oaep_decode + class PKCS1OAEP_Cipher: """Cipher object for PKCS#1 v1.5 OAEP. @@ -68,7 +70,7 @@ class PKCS1OAEP_Cipher: if mgfunc: self._mgf = mgfunc else: - self._mgf = lambda x,y: MGF1(x,y,self._hashObj) + self._mgf = lambda x, y: MGF1(x, y, self._hashObj) self._label = _copy_bytes(None, None, label) self._randfunc = randfunc @@ -105,7 +107,7 @@ class PKCS1OAEP_Cipher: # See 7.1.1 in RFC3447 modBits = Cryptodome.Util.number.size(self._key.n) - k = ceil_div(modBits, 8) # Convert from bits to bytes + k = ceil_div(modBits, 8) # Convert from bits to bytes hLen = self._hashObj.digest_size mLen = len(message) @@ -159,22 +161,18 @@ class PKCS1OAEP_Cipher: # See 7.1.2 in RFC3447 modBits = Cryptodome.Util.number.size(self._key.n) - k = ceil_div(modBits,8) # Convert from bits to bytes + k = ceil_div(modBits, 8) # Convert from bits to bytes hLen = self._hashObj.digest_size # Step 1b and 1c - if len(ciphertext) != k or k<hLen+2: + if len(ciphertext) != k or k < hLen+2: raise ValueError("Ciphertext with incorrect length.") # Step 2a (O2SIP) ct_int = bytes_to_long(ciphertext) - # Step 2b (RSADP) - m_int = self._key._decrypt(ct_int) - # Complete step 2c (I2OSP) - em = long_to_bytes(m_int, k) + # Step 2b (RSADP) and step 2c (I2OSP) + em = self._key._decrypt_to_bytes(ct_int) # Step 3a lHash = self._hashObj.new(self._label).digest() - # Step 3b - y = em[0] # y must be 0, but we MUST NOT check it here in order not to # allow attacks like Manger's (http://dl.acm.org/citation.cfm?id=704143) maskedSeed = em[1:hLen+1] @@ -187,22 +185,17 @@ class PKCS1OAEP_Cipher: dbMask = self._mgf(seed, k-hLen-1) # Step 3f db = strxor(maskedDB, dbMask) - # Step 3g - one_pos = hLen + db[hLen:].find(b'\x01') - lHash1 = db[:hLen] - invalid = bord(y) | int(one_pos < hLen) - hash_compare = strxor(lHash1, lHash) - for x in hash_compare: - invalid |= bord(x) - for x in db[hLen:one_pos]: - invalid |= bord(x) - if invalid != 0: + # Step 3b + 3g + res = oaep_decode(em, lHash, db) + if res <= 0: raise ValueError("Incorrect decryption.") # Step 4 - return db[one_pos + 1:] + return db[res:] + def new(key, hashAlgo=None, mgfunc=None, label=b'', randfunc=None): - """Return a cipher object :class:`PKCS1OAEP_Cipher` that can be used to perform PKCS#1 OAEP encryption or decryption. + """Return a cipher object :class:`PKCS1OAEP_Cipher` + that can be used to perform PKCS#1 OAEP encryption or decryption. :param key: The key object to use to encrypt or decrypt the message. @@ -236,4 +229,3 @@ def new(key, hashAlgo=None, mgfunc=None, label=b'', randfunc=None): if randfunc is None: randfunc = Random.get_random_bytes return PKCS1OAEP_Cipher(key, hashAlgo, mgfunc, label, randfunc) - |