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Remove AlfCrypto libraries and perform everything in Python

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The old AlfCrypto DLL, SO and DYLIB files are ancient,
I don't have the systems to recompile them all, they
cause issues on ARM Macs, and I doubt with all the Python
improvements over the last years that they have a significant
performance advantage. And even if that's the case, nobody is
importing hundreds of DRM books at the same time so it shouldn't
hurt if some decryptions might take a bit longer.
This commit is contained in:
NoDRM
2022-08-06 20:13:19 +02:00
parent 9276d77f63
commit 410e086d08
10 changed files with 81 additions and 443 deletions
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49
DeDRM_plugin/mobidedrm.py
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@@ -80,10 +80,7 @@ import sys
import os
import struct
import binascii
try:
from alfcrypto import Pukall_Cipher
except:
print("AlfCrypto not found. Using python PC1 implementation.")
from alfcrypto import Pukall_Cipher
from utilities import SafeUnbuffered
@@ -140,41 +137,8 @@ def PC1(key, src, decryption=True):
# if we can get it from alfcrypto, use that
try:
return Pukall_Cipher().PC1(key,src,decryption)
except NameError:
pass
except TypeError:
pass
# use slow python version, since Pukall_Cipher didn't load
sum1 = 0;
sum2 = 0;
keyXorVal = 0;
if len(key)!=16:
DrmException ("PC1: Bad key length")
wkey = []
for i in range(8):
wkey.append(key[i*2]<<8 | key[i*2+1])
dst = bytearray(len(src))
for i in range(len(src)):
temp1 = 0;
byteXorVal = 0;
for j in range(8):
temp1 ^= wkey[j]
sum2 = (sum2+j)*20021 + sum1
sum1 = (temp1*346)&0xFFFF
sum2 = (sum2+sum1)&0xFFFF
temp1 = (temp1*20021+1)&0xFFFF
byteXorVal ^= temp1 ^ sum2
curByte = src[i]
if not decryption:
keyXorVal = curByte * 257;
curByte = ((curByte ^ (byteXorVal >> 8)) ^ byteXorVal) & 0xFF
if decryption:
keyXorVal = curByte * 257;
for j in range(8):
wkey[j] ^= keyXorVal;
dst[i] = curByte
return bytes(dst)
except:
raise
# accepts unicode returns unicode
def checksumPid(s):
@@ -232,12 +196,7 @@ class MobiBook:
pass
def __init__(self, infile):
print("MobiDeDrm v{0:s}.\nCopyright © 2008-2020 The Dark Reverser, Apprentice Harper et al.".format(__version__))
try:
from alfcrypto import Pukall_Cipher
except:
print("AlfCrypto not found. Using python PC1 implementation.")
print("MobiDeDrm v{0:s}.\nCopyright © 2008-2022 The Dark Reverser, Apprentice Harper et al.".format(__version__))
# initial sanity check on file
self.data_file = open(infile, 'rb').read()