Help with script error - Printable Version +- Python Forum (https://python-forum.io) +-- Forum: Python Coding (https://python-forum.io/forum-7.html) +--- Forum: General Coding Help (https://python-forum.io/forum-8.html) +--- Thread: Help with script error (/thread-3605.html) Pages:
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Help with script error - mason28 - Jun-06-2017 Hi everyone, I found the following code at (devnote.stokemaster.com/2009/07/simple-way-to-encrpt-and-decrypt-short.html). When I put print statements to debug, the script dies in the function "p3_encrypt" at the line "stream = array('L', plain+'0000'[n&3:])". I am using Python 2.7. How do fix it to make it work? from string import join from array import array #import sha import hashlib from time import time class CryptError(Exception): pass def _hash(str): return hashlib.sha224(str).digest() _ivlen = 16 _maclen = 8 _state = _hash(`time()`) try: import os _pid = `os.getpid()` except ImportError, AttributeError: _pid = '' def _expand_key(key, clen): blocks = (clen+19)/20 xkey=[] seed=key for i in xrange(blocks): seed=hashlib.sha224(key+seed).digest() xkey.append(seed) j = join(xkey,'') return array ('L', j) def p3_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 = [`time()`, _pid, _state, `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 ####### Script dies here! ########### stream = array('L', plain+'0000'[n&3:]) # pad to fill 32-bit words xkey = _expand_key(k_enc, n+4) for i in xrange(len(stream)): stream[i] = stream[i] ^ xkey[i] ct = nonce + stream.tostring()[:n] auth = _hmac(ct, k_auth) return ct + auth[:_maclen] def p3_decrypt(cipher,key): 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('L', stream) xkey = _expand_key (k_enc, n+4) for i in xrange (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 xrange(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() _hmac_setup() #_test() #_speed() # uncomment to run speed test RE: Help with script error - buran - Jun-06-2017 what does it mean 'dies", i.e. post full traceback in error tags. Also if you made any changes, post the code YOU are running, not the one you have copy/paste from somewhere. There could be unintentional errors introduced by you. RE: Help with script error - mason28 - Jun-06-2017 (Jun-06-2017, 05:25 PM)buran Wrote: what does it mean 'dies", i.e. post full traceback in error tags. It stops running after that line. I simple call p3_encrypt like this (p3_encrypt('hello', 'some_salt;) and put print statements to debug. RE: Help with script error - buran - Jun-06-2017 please, follow the instructions where do you put this line (p3_encrypt('hello', 'some_salt;)there is obvious error in this line - the semicolon after some_salt also if it dies at the line you say, there should be some error RE: Help with script error - mason28 - Jun-06-2017 (Jun-06-2017, 05:50 PM)buran Wrote: please, follow the instructions Sorry I had a typo. I call the p3_encrypt like this: p3_encrypt('hello', 'some_salt') Ah I got the error message now. It says "ValueError: string length not a multiple of item size" at that line. RE: Help with script error - buran - Jun-06-2017 Is it THAT difficult to post THE FULL TRACEBACK in error tags, when asked so? It has way more info, not just the last line... Help us to help you RE: Help with script error - volcano63 - Jun-06-2017 (Jun-06-2017, 05:54 PM)mason28 Wrote: Ah I got the error message now. It says "ValueError: string length not a multiple of item size" at that line.OK, that is pretty obvious, I think - length of one strings must be a a multiple of the length of another. Which one may be longer - RTM. (Jun-06-2017, 06:36 PM)buran Wrote: Is it THAT difficult to post THE FULL TRACEBACK in error tags. It has way more info, not just the last line... Help us to help youThough in general you are absolutely right, I believe that in this case the last line is enough RE: Help with script error - buran - Jun-06-2017 (Jun-06-2017, 06:54 PM)volcano63 Wrote: Though in general you are absolutely right, I believe that in this case the last line is enoughIt's arguably enough. Obviously it is not enough for the OP to solve his/her problem. Given that this error description is not present in the published code, the chain of executed statements would allow us to help him better. e.g. which string, which item, etc. RE: Help with script error - mason28 - Jun-07-2017 encrypted = p3_encrypt('hello', 'some_salt') File "/home/modules/mycrypt.py", line 59, in p3_encrypt stream = array('L', plain+'0000'[n&3:]) ValueError: string length not a multiple of item sizeHow do I fix that error? Can anyone enlighten me RE: Help with script error - mason28 - Jun-07-2017 Found a fix at https://mail.python.org/pipermail/python-list/2010-January/563791.html Thanks guys |