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Various small fixes and clean ups

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This commit is contained in:
Helder Eijs 2018-04-03 11:18:31 +02:00
parent c1834322b6
commit 53be0708d7
5 changed files with 63 additions and 34 deletions
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25
lib/Crypto/Cipher/PKCS1_OAEP.py
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@ -23,7 +23,7 @@
from Crypto.Signature.pss import MGF1
import Crypto.Hash.SHA1
from Crypto.Util.py3compat import *
from Crypto.Util.py3compat import bord, _copy_bytes
import Crypto.Util.number
from Crypto.Util.number import ceil_div, bytes_to_long, long_to_bytes
from Crypto.Util.strxor import strxor
@ -70,7 +70,7 @@ class PKCS1OAEP_Cipher:
else:
self._mgf = lambda x,y: MGF1(x,y,self._hashObj)
self._label = bstr(label)
self._label = _copy_bytes(None, None, label)
self._randfunc = randfunc
def can_encrypt(self):
@ -102,24 +102,23 @@ class PKCS1OAEP_Cipher:
:raises ValueError:
if the message is too long.
"""
# TODO: Verify the key is RSA
# See 7.1.1 in RFC3447
modBits = Crypto.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)
# Step 1b
ps_len = k-mLen-2*hLen-2
if ps_len<0:
ps_len = k - mLen - 2 * hLen - 2
if ps_len < 0:
raise ValueError("Plaintext is too long.")
# Step 2a
lHash = self._hashObj.new(self._label).digest()
# Step 2b
ps = bchr(0x00)*ps_len
ps = b'\x00' * ps_len
# Step 2c
db = lHash + ps + bchr(0x01) + message
db = lHash + ps + b'\x01' + _copy_bytes(None, None, message)
# Step 2d
ros = self._randfunc(hLen)
# Step 2e
@ -131,7 +130,7 @@ class PKCS1OAEP_Cipher:
# Step 2h
maskedSeed = strxor(ros, seedMask)
# Step 2i
em = bchr(0x00) + maskedSeed + maskedDB
em = b'\x00' + maskedSeed + maskedDB
# Step 3a (OS2IP)
em_int = bytes_to_long(em)
# Step 3b (RSAEP)
@ -167,7 +166,7 @@ class PKCS1OAEP_Cipher:
if len(ciphertext) != k or k<hLen+2:
raise ValueError("Ciphertext with incorrect length.")
# Step 2a (O2SIP)
ct_int = bytes_to_long(bstr(ciphertext))
ct_int = bytes_to_long(ciphertext)
# Step 2b (RSADP)
m_int = self._key._decrypt(ct_int)
# Complete step 2c (I2OSP)
@ -190,20 +189,20 @@ class PKCS1OAEP_Cipher:
db = strxor(maskedDB, dbMask)
# Step 3g
valid = 1
one = db[hLen:].find(bchr(0x01))
one = db[hLen:].find(b'\x01')
lHash1 = db[:hLen]
if lHash1!=lHash:
valid = 0
if one<0:
valid = 0
if bord(y)!=0:
if bord(y) != 0:
valid = 0
if not valid:
raise ValueError("Incorrect decryption.")
# Step 4
return db[hLen+one+1:]
def new(key, hashAlgo=None, mgfunc=None, label=b(''), randfunc=None):
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.
:param key: