Dec-22-2018, 06:40 PM
Hi everyone,
I need help with converting an encryption module (p3.py) written for Python2 to Python3.
First, I converted the module to python3 using the online python 2 to 3 converter (http://www.pythonconverter.com/). When I tried to use the converted module, I get errors.
I have attached the converted source below. The encryption module imports base64i, which I have also included:
Error 1:
Error 2:
Error 3:
Error 4:
Error 5:
Error 6:
Please help me check if I have fixed those errors correctly and for those that I don't know how, please suggest a fix.
Thank you very much in anticipation
I need help with converting an encryption module (p3.py) written for Python2 to Python3.
First, I converted the module to python3 using the online python 2 to 3 converter (http://www.pythonconverter.com/). When I tried to use the converted module, I get errors.
I have attached the converted source below. The encryption module imports base64i, which I have also included:
# p3.py
from string import join
from array import array
import base64i
import hashlib
from time import time
# This fix https://mail.python.org/pipermail/python-list/2010-January/563791.html
for typecode in 'IL':
if len(array(typecode, [0]).tostring()) == 4:
uint32 = typecode
break
else:
raise RuntimeError("Neither 'I' nor 'L' are unsigned 32-bit integers.")
#print('Content-Type: text/html; charset=UTF-8\n\n')
#http://devnote.stokemaster.com/2009/07/simple-way-to-encrpt-and-decrypt-short.html
class CryptError(Exception): pass
def _hash(str): return hashlib.sha224(str).digest()
_ivlen = 16
_maclen = 8
_state = _hash(repr(time()))
try:
import os
_pid = repr(os.getpid())
except ImportError as AttributeError:
_pid = ''
def _expand_key(key, clen):
blocks = (clen+19)/20
xkey=[]
seed=key
for i in range(blocks):
seed=hashlib.sha224(key+seed).digest()
xkey.append(seed)
j = join(xkey,'')
return array (uint32, j)
def encrypt(plain,key):
global _state
H = _hash
# change _state BEFORE using it to compute nonce, in case there's
# a thread switch between computing the nonce and folding it into
# the state. This way if two threads compute a nonce from the
# same data, they won't both get the same nonce. (There's still
# a small danger of a duplicate nonce--see below).
_state = 'X'+_state
# Attempt to make nlist unique for each call, so we can get a
# unique nonce. It might be good to include a process ID or
# something, but I don't know if that's portable between OS's.
# Since is based partly on both the key and plaintext, in the
# worst case (encrypting the same plaintext with the same key in
# two separate Python instances at the same time), you might get
# identical ciphertexts for the identical plaintexts, which would
# be a security failure in some applications. Be careful.
nlist = [repr(time()), _pid, _state, repr(len(plain)),plain, key]
nonce = H(join(nlist,','))[:_ivlen]
_state = H('update2'+_state+nonce)
k_enc, k_auth = H('enc'+key+nonce), H('auth'+key+nonce)
n=len(plain) # cipher size not counting IV
stream = array(uint32, plain+'0000'[n&3:])
xkey = _expand_key(k_enc, n+4)
for i in range(len(stream)):
stream[i] = stream[i] ^ xkey[i]
ct = nonce + stream.tostring()[:n]
auth = _hmac(ct, k_auth)
#return ct + auth[:_maclen]
return base64i.urlsafe_b64encode(ct + auth[:_maclen])
def decrypt(cipher,key):
cipher=base64i.urlsafe_b64decode(cipher)
H = _hash
n=len(cipher)-_ivlen-_maclen # length of ciphertext
if n < 0:
raise CryptError("invalid ciphertext")
nonce,stream,auth = \
cipher[:_ivlen], cipher[_ivlen:-_maclen]+'0000'[n&3:],cipher[-_maclen:]
k_enc, k_auth = H('enc'+key+nonce), H('auth'+key+nonce)
vauth = _hmac (cipher[:-_maclen], k_auth)[:_maclen]
if auth != vauth:
raise CryptError("invalid key or ciphertext")
stream = array(uint32, stream)
xkey = _expand_key (k_enc, n+4)
for i in range (len(stream)):
stream[i] = stream[i] ^ xkey[i]
plain = stream.tostring()[:n]
return plain
# RFC 2104 HMAC message authentication code
# This implementation is faster than Python 2.2's hmac.py, and also works in
# old Python versions (at least as old as 1.5.2).
from string import translate
def _hmac_setup():
global _ipad, _opad, _itrans, _otrans
_itrans = array('B',[0]*256)
_otrans = array('B',[0]*256)
for i in range(256):
_itrans[i] = i ^ 0x36
_otrans[i] = i ^ 0x5c
_itrans = _itrans.tostring()
_otrans = _otrans.tostring()
_ipad = '\x36'*64
_opad = '\x5c'*64
def _hmac(msg, key):
if len(key)>64:
key=sha.new(key).digest()
ki = (translate(key,_itrans)+_ipad)[:64] # inner
ko = (translate(key,_otrans)+_opad)[:64] # outer
return hashlib.sha224(ko+hashlib.sha224(ki+msg).digest()).digest()
#
# benchmark and unit test
#
def _time_p3(n=1000,len=20):
plain="a"*len
t=time()
for i in range(n):
encrypt(plain,"abcdefgh")
dt=time()-t
print("plain p3:", n,len,dt,"sec =",n*len/dt,"bytes/sec")
def _speed():
_time_p3(len=5)
_time_p3()
_time_p3(len=200)
_time_p3(len=2000,n=100)
def _test():
e=encrypt
d=decrypt
plain="test plaintext"
key = "test key"
c1 = e(plain,key)
c2 = e(plain,key)
assert c1!=c2
assert d(c2,key)==plain
assert d(c1,key)==plain
c3 = c2[:20]+chr(1+ord(c2[20]))+c2[21:] # change one ciphertext character
try:
print(d(c3,key)) # should throw exception
print("auth verification failure")
except CryptError:
pass
try:
print(d(c2,'wrong key')) # should throw exception
print("test failure")
except CryptError:
pass
_hmac_setup()
#_test()
#_speed() # uncomment to run speed test#base64i
"""RFC 3548: Base16, Base32, Base64 Data Encodings"""
# Modified 04-Oct-1995 by Jack Jansen to use binascii module
# Modified 30-Dec-2003 by Barry Warsaw to add full RFC 3548 support
import re
import struct
import binascii
__all__ = [
# Legacy interface exports traditional RFC 1521 Base64 encodings
'encode', 'decode', 'encodestring', 'decodestring',
# Generalized interface for other encodings
'b64encode', 'b64decode', 'b32encode', 'b32decode',
'b16encode', 'b16decode',
# Standard Base64 encoding
'standard_b64encode', 'standard_b64decode',
# Some common Base64 alternatives. As referenced by RFC 3458, see thread
# starting at:
#
# http://zgp.org/pipermail/p2p-hackers/2001-September/000316.html
'urlsafe_b64encode', 'urlsafe_b64decode',
]
_translation = [chr(_x) for _x in range(256)]
EMPTYSTRING = ''
def _translate(s, altchars):
translation = _translation[:]
for k, v in list(altchars.items()):
translation[ord(k)] = v
return s.translate(''.join(translation))
# Base64 encoding/decoding uses binascii
def b64encode(s, altchars=None):
"""Encode a string using Base64.
s is the string to encode. Optional altchars must be a string of at least
length 2 (additional characters are ignored) which specifies an
alternative alphabet for the '+' and '/' characters. This allows an
application to e.g. generate url or filesystem safe Base64 strings.
The encoded string is returned.
"""
# Strip off the trailing newline
encoded = binascii.b2a_base64(s)[:-1]
if altchars is not None:
return _translate(encoded, {'+': altchars[0], '/': altchars[1]})
return encoded
def b64decode(s, altchars=None):
"""Decode a Base64 encoded string.
s is the string to decode. Optional altchars must be a string of at least
length 2 (additional characters are ignored) which specifies the
alternative alphabet used instead of the '+' and '/' characters.
The decoded string is returned. A TypeError is raised if s were
incorrectly padded or if there are non-alphabet characters present in the
string.
"""
if altchars is not None:
s = _translate(s, {altchars[0]: '+', altchars[1]: '/'})
try:
return binascii.a2b_base64(s)
except binascii.Error as msg:
# Transform this exception for consistency
raise TypeError(msg)
def standard_b64encode(s):
"""Encode a string using the standard Base64 alphabet.
s is the string to encode. The encoded string is returned.
"""
return b64encode(s)
def standard_b64decode(s):
"""Decode a string encoded with the standard Base64 alphabet.
s is the string to decode. The decoded string is returned. A TypeError
is raised if the string is incorrectly padded or if there are non-alphabet
characters present in the string.
"""
return b64decode(s)
def urlsafe_b64encode(s):
"""Encode a string using a url-safe Base64 alphabet.
s is the string to encode. The encoded string is returned. The alphabet
uses '-' instead of '+' and '_' instead of '/'.
"""
return b64encode(s, '-_')
def urlsafe_b64decode(s):
"""Decode a string encoded with the standard Base64 alphabet.
s is the string to decode. The decoded string is returned. A TypeError
is raised if the string is incorrectly padded or if there are non-alphabet
characters present in the string.
The alphabet uses '-' instead of '+' and '_' instead of '/'.
"""
return b64decode(s, '-_')
# Base32 encoding/decoding must be done in Python
_b32alphabet = {
0: 'A', 9: 'J', 18: 'S', 27: '3',
1: 'B', 10: 'K', 19: 'T', 28: '4',
2: 'C', 11: 'L', 20: 'U', 29: '5',
3: 'D', 12: 'M', 21: 'V', 30: '6',
4: 'E', 13: 'N', 22: 'W', 31: '7',
5: 'F', 14: 'O', 23: 'X',
6: 'G', 15: 'P', 24: 'Y',
7: 'H', 16: 'Q', 25: 'Z',
8: 'I', 17: 'R', 26: '2',
}
_b32tab = [v for v in list(_b32alphabet.values())]
_b32rev = dict([(v, int(k)) for k, v in list(_b32alphabet.items())])
def b32encode(s):
"""Encode a string using Base32.
s is the string to encode. The encoded string is returned.
"""
parts = []
quanta, leftover = divmod(len(s), 5)
# Pad the last quantum with zero bits if necessary
if leftover:
s += ('\0' * (5 - leftover))
quanta += 1
for i in range(quanta):
# c1 and c2 are 16 bits wide, c3 is 8 bits wide. The intent of this
# code is to process the 40 bits in units of 5 bits. So we take the 1
# leftover bit of c1 and tack it onto c2. Then we take the 2 leftover
# bits of c2 and tack them onto c3. The shifts and masks are intended
# to give us values of exactly 5 bits in width.
c1, c2, c3 = struct.unpack('!HHB', s[i*5:(i+1)*5])
c2 += (c1 & 1) << 16 # 17 bits wide
c3 += (c2 & 3) << 8 # 10 bits wide
parts.extend([_b32tab[c1 >> 11], # bits 1 - 5
_b32tab[(c1 >> 6) & 0x1f], # bits 6 - 10
_b32tab[(c1 >> 1) & 0x1f], # bits 11 - 15
_b32tab[c2 >> 12], # bits 16 - 20 (1 - 5)
_b32tab[(c2 >> 7) & 0x1f], # bits 21 - 25 (6 - 10)
_b32tab[(c2 >> 2) & 0x1f], # bits 26 - 30 (11 - 15)
_b32tab[c3 >> 5], # bits 31 - 35 (1 - 5)
_b32tab[c3 & 0x1f], # bits 36 - 40 (1 - 5)
])
encoded = EMPTYSTRING.join(parts)
# Adjust for any leftover partial quanta
if leftover == 1:
return encoded[:-6] + '======'
elif leftover == 2:
return encoded[:-4] + '===='
elif leftover == 3:
return encoded[:-3] + '==='
elif leftover == 4:
return encoded[:-1] + '='
return encoded
def b32decode(s, casefold=False, map01=None):
"""Decode a Base32 encoded string.
s is the string to decode. Optional casefold is a flag specifying whether
a lowercase alphabet is acceptable as input. For security purposes, the
default is False.
RFC 3548 allows for optional mapping of the digit 0 (zero) to the letter O
(oh), and for optional mapping of the digit 1 (one) to either the letter I
(eye) or letter L (el). The optional argument map01 when not None,
specifies which letter the digit 1 should be mapped to (when map01 is not
None, the digit 0 is always mapped to the letter O). For security
purposes the default is None, so that 0 and 1 are not allowed in the
input.
The decoded string is returned. A TypeError is raised if s were
incorrectly padded or if there are non-alphabet characters present in the
string.
"""
quanta, leftover = divmod(len(s), 8)
if leftover:
raise TypeError('Incorrect padding')
# Handle section 2.4 zero and one mapping. The flag map01 will be either
# False, or the character to map the digit 1 (one) to. It should be
# either L (el) or I (eye).
if map01:
s = _translate(s, {'0': 'O', '1': map01})
if casefold:
s = s.upper()
# Strip off pad characters from the right. We need to count the pad
# characters because this will tell us how many null bytes to remove from
# the end of the decoded string.
padchars = 0
mo = re.search('(?P<pad>[=]*)$', s)
if mo:
padchars = len(mo.group('pad'))
if padchars > 0:
s = s[:-padchars]
# Now decode the full quanta
parts = []
acc = 0
shift = 35
for c in s:
val = _b32rev.get(c)
if val is None:
raise TypeError('Non-base32 digit found')
acc += _b32rev[c] << shift
shift -= 5
if shift < 0:
parts.append(binascii.unhexlify(hex(acc)[2:-1]))
acc = 0
shift = 35
# Process the last, partial quanta
last = binascii.unhexlify(hex(acc)[2:-1])
if padchars == 1:
last = last[:-1]
elif padchars == 3:
last = last[:-2]
elif padchars == 4:
last = last[:-3]
elif padchars == 6:
last = last[:-4]
elif padchars != 0:
raise TypeError('Incorrect padding')
parts.append(last)
return EMPTYSTRING.join(parts)
# RFC 3548, Base 16 Alphabet specifies uppercase, but hexlify() returns
# lowercase. The RFC also recommends against accepting input case
# insensitively.
def b16encode(s):
"""Encode a string using Base16.
s is the string to encode. The encoded string is returned.
"""
return binascii.hexlify(s).upper()
def b16decode(s, casefold=False):
"""Decode a Base16 encoded string.
s is the string to decode. Optional casefold is a flag specifying whether
a lowercase alphabet is acceptable as input. For security purposes, the
default is False.
The decoded string is returned. A TypeError is raised if s were
incorrectly padded or if there are non-alphabet characters present in the
string.
"""
if casefold:
s = s.upper()
if re.search('[^0-9A-F]', s):
raise TypeError('Non-base16 digit found')
return binascii.unhexlify(s)
# Legacy interface. This code could be cleaned up since I don't believe
# binascii has any line length limitations. It just doesn't seem worth it
# though.
MAXLINESIZE = 76 # Excluding the CRLF
MAXBINSIZE = (MAXLINESIZE//4)*3
def encode(input, output):
"""Encode a file."""
while True:
s = input.read(MAXBINSIZE)
if not s:
break
while len(s) < MAXBINSIZE:
ns = input.read(MAXBINSIZE-len(s))
if not ns:
break
s += ns
line = binascii.b2a_base64(s)
output.write(line)
def decode(input, output):
"""Decode a file."""
while True:
line = input.readline()
if not line:
break
s = binascii.a2b_base64(line)
output.write(s)
def encodestring(s):
"""Encode a string."""
pieces = []
for i in range(0, len(s), MAXBINSIZE):
chunk = s[i : i + MAXBINSIZE]
pieces.append(binascii.b2a_base64(chunk))
return "".join(pieces)
def decodestring(s):
"""Decode a string."""
return binascii.a2b_base64(s)
# Useable as a script...
def test():
"""Small test program"""
import sys, getopt
try:
opts, args = getopt.getopt(sys.argv[1:], 'deut')
except getopt.error as msg:
sys.stdout = sys.stderr
print(msg)
print("""usage: %s [-d|-e|-u|-t] [file|-]
-d, -u: decode
-e: encode (default)
-t: encode and decode string 'Aladdin:open sesame'"""%sys.argv[0])
sys.exit(2)
func = encode
for o, a in opts:
if o == '-e': func = encode
if o == '-d': func = decode
if o == '-u': func = decode
if o == '-t': test1(); return
if args and args[0] != '-':
func(open(args[0], 'rb'), sys.stdout)
else:
func(sys.stdin, sys.stdout)
def test1():
s0 = "Aladdin:open sesame"
s1 = encodestring(s0)
s2 = decodestring(s1)
print(s0, repr(s1), s2)
if __name__ == '__main__':
test()I tried to fix the errors as follows:Error 1:
Error: from string import join
ImportError: cannot import name 'join'def _expand_key(key, clen):
blocks = (clen+19)/20
xkey=[]
seed=key
for i in range(blocks):
seed=hashlib.sha224(key+seed).digest()
xkey.append(seed)
j = join(xkey,'')
return array (uint32, j)Fixed as:j = ''.join(xkey)Is that correct?
Error 2:
Error: def _hash(str): return hashlib.sha224(str).digest()
TypeError: Unicode-objects must be encoded before hashingdef _hash(str): return hashlib.sha224(str.encode()).digest()Is that correct?
Error 3:
Error: from string import translate
ImportError: cannot import name 'translate'from string import translate
def _hmac(msg, key):
if len(key)>64:
key=sha.new(key).digest()
ki = (translate(key,_itrans)+_ipad)[:64] # inner
ko = (translate(key,_otrans)+_opad)[:64] # outer
return hashlib.sha224(ko+hashlib.sha224(ki+msg).digest()).digest()How do I fix this?Error 4:
Error: _state = 'X'+_state
TypeError: Can't convert 'bytes' object to str implicitly_state = 'X' + str(_state)Is that correct?
Error 5:
Error: nonce = H(','.join(nlist))[:_ivlen]
TypeError: sequence item 2: expected str instance, bytes foundnonce = H(','.join(str(nlist)))[:_ivlen]]Is that correct?Error 6:
Error: stream = array(uint32, plain+'0000'[n&3:])
TypeError: cannot use a str to initialize an array with typecode 'I'Please help me check if I have fixed those errors correctly and for those that I don't know how, please suggest a fix.
Thank you very much in anticipation
