Fix for broken book keys

This commit is contained in:
Aldo Bleeker 2021-01-28 13:06:59 +01:00
parent 8d2d6627cf
commit 33b9630ca5
2 changed files with 8 additions and 9 deletions

View File

@ -415,12 +415,12 @@ def decryptBook(userkey, inpath, outpath):
return 1
bookkey = rsa.decrypt(codecs.decode(bookkey.encode('ascii'), 'base64'))
# Padded as per RSAES-PKCS1-v1_5
if len(bookkey) != 16:
if bookkey[-17] != '\x00' and bookkey[-17] != 0:
if len(bookkey) > 16:
if bookkey[-17] == '\x00' or bookkey[-17] == 0:
bookkey = bookkey[-16:]
else:
print("Could not decrypt {0:s}. Wrong key".format(os.path.basename(inpath)))
return 2
else:
bookkey = bookkey[-16:]
encryption = inf.read('META-INF/encryption.xml')
decryptor = Decryptor(bookkey, encryption)
kwds = dict(compression=ZIP_DEFLATED, allowZip64=False)

View File

@ -1599,11 +1599,10 @@ class PDFDocument(object):
bookkey = rsa.decrypt(bookkey)
#if bookkey[0] != 2:
# raise ADEPTError('error decrypting book session key')
try:
index = bookkey.index(b'\0') + 1
bookkey = bookkey[index:]
except ValueError:
pass
if len(bookkey) > 16:
if bookkey[-17] == '\x00' or bookkey[-17] == 0:
bookkey = bookkey[-16:]
length = 16
ebx_V = int_value(param.get('V', 4))
ebx_type = int_value(param.get('EBX_ENCRYPTIONTYPE', 6))
# added because of improper booktype / decryption book session key errors