CODEWITHSUNDEEP
pythonnon-ascii-characters
shoomy
shoomy

Reputation: 7

excluding non-ascii characters in python

I have a script which uses a dictionary to decrypt an encrypted message, the problem is the decryption process produces a lot of junk (a.k.a non-ascii) characters. Here is my code:

from Crypto.Cipher import AES
import base64
import os

BLOCK_SIZE = 32

PADDING = '{'

# Encrypted text to decrypt
encrypted = "WI4wBGwWWNcxEovAe3p+GrpK1GRRQcwckVXypYlvdHs="

DecodeAES = lambda c, e: c.decrypt(base64.b64decode(e)).rstrip(PADDING)

adib = open('words.txt')
for line in adib.readlines():
    secret = line.rstrip('\n')
    if (secret[-1:] == "\n"):
        print "Error, new line character at the end of the string. This will not match!"
    elif (len(secret) >= 32):
        print "Error, string too long. Must be less than 32 characters."
    else:
        # create a cipher object using the secret
        cipher = AES.new(secret + (BLOCK_SIZE - len(secret) % BLOCK_SIZE) * PADDING)

        # decode the encoded string 
        decoded = DecodeAES(cipher, encrypted)
        print decoded+"\n"

what I have thought of so far is converting decoded string into Ascii then exclude non-ascii characters but it didn't work.

Upvotes: 0

Views: 1138

Answers (3)

Nitin Kandhare
Nitin Kandhare

Reputation: 1

if six.PY2:
    if isinstance(input_data, str):
        input_data = input_data.decode('ascii', 'ignore').encode('ascii')
    else:
        input_data = input_data.encode('ascii', 'ignore')
else:
    six.PY3
    input_data = str(input_data)

print(input_data)

Upvotes: 0

A. STEFANI
A. STEFANI

Reputation: 6737

This version will work:

#!/usr/bin/env python
# -*- coding: UTF-8 -*-

def evaluate_string_is_ascii(mystring):
    is_full_ascii=True
    for c in mystring:
        try:
            if ord(c)>0 and ord(c)<=127:
                #print c,"strict ascii =KEEP"
                pass
            elif ord(c)>127  and ord(c)<=255:
                #print c,"extended ascii code =TRASH"
                is_full_ascii=False
                break
            else:
               # print c,"no ascii  =TRASH"
                is_full_ascii=False
                break
        except:
            #print c,"no ascii  =TRASH"
            is_full_ascii=False
            break
    return is_full_ascii


my_text_content="""azertwxcv
123456789
456dqsdq13
o@��nS��?t#�
lkjal�
kfldjkjl&é"""

for line in my_text_content.split('\n'):

    #check if line contain only ascii
    if evaluate_string_is_ascii(line)==True:

        #print the line
        print line

Upvotes: 0

Bunny Rabbit
Bunny Rabbit

Reputation: 8411

You can remove non ascii characters like this : EDIT : updated with the decode first.

output = 'string with some non-ascii characters��@$���9�HK��F�23 some more char'
output = output.decode('utf-8').encode('ascii', 'ignore')

Upvotes: 1

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