(Jul 10, 2018 07:02 PM)Sparkling Jack Wrote:  Hello guys.
Recently I was needed to make a python script to replace misorderd base64 string to plaint text in a file.

For example:
base64decode(textorder("Wavxmd5V3b=U"))     -->   iloveyou
original base64 code of "iloveyou" is aWxvdmV5b3U=

Here is the code:

Code

def changeStr(str):
    newStr = list(str)
    resStr = list(str)
    for i in xrange(0,len(newStr),2):
        if i==len(newStr)-1:
            resStr[i] = newStr[i]
        else:
            resStr[i]=newStr[i+1]
            resStr[i+1] = newStr[i]
    str = ''.join(resStr)
    return str
def base64Decode(str):
    src1=changeStr(str)
    result=base64.b64decode(src1)
    return result
def find_str(s, char):
   index = 0
   res = []
   if char in s:
       c = char[0]
       for ch in s:
           if ch == c:
               if s[index:index+len(char)] == char:
                   res.append(index+len(char))
           index += 1
   return res
def find_End(str):
    index =0;
    if "\"" in str:
        for ch in str:
            if ch == "\"":
                return str[:index]
            index+=1
    return "None"
if __name__ == '__main__':
    infile = open('1.txt')
    outputfile = open('2.txt','w')
    for line in infile:
        pos = find_str(line, "base64decode(textorder(")
        if pos:
            for i in reversed(pos):
                source =  find_End(line[i+1:])
                result = base64Decode(source)
                src = "base64decode(textorder(\""+source+"\"))"
                line = line.replace(src, "\""+result+"\"")
    outputfile.write(line)

Hope this will be a bit of help for you!

(Aug 3, 2018 08:19 PM)TyrantKingBen Wrote:  The nice thing about Python is almost anything can be accomplished in very little code. Your changeStr can be rewritten to make use of Python's features.

One Liner:

Code

def changeStr(scrambled):
   return "".join([a + b for b, a in zip(scrambled[::2], scrambled[1::2])]) + (scrambled[-1] if (len(scrambled) % 2) else "")

Expanded:

Code

def changeStr(scrambled):
   unscrambled = "".join([a + b for b, a in zip(scrambled[::2], scrambled[1::2])])
   
   if (len(scrambled) % 2):
        unscrambled += scrambled[-1]
   
   return unscrambled

Also, it's tempting to call the parameter 'str', but that will override the 'str' function, so best to avoid that habit.