Convert to binary and convert back to strings

[Harlin Seritt]

On Feb 21, 7:12 pm, Larry Bates <lba... at websafe.com> wrote:
> Harlin Seritt wrote:
> > Hi...
>
> > I would like to take a string like 'supercalifragilisticexpialidocius'
> > and write it to a file in binary forms -- this way a user cannot read
> > the string in case they were try to open in something like ascii text
> > editor. I'd also like to be able to read the binary formed data back
> > into string format so that it shows the original value. Is there any
> > way to do this in Python?
>
> > Thanks!
>
> > Harlin
>
> I promise you that everything written to a file is done in binary.
> Computers don't know how to work with anything BUT binary.  I think
> what you want to do is to encrypt/obstifucate the string.  For that
> you will need to encrypt the string, write it out, read it back in,
> and decrypt it.  If you want it to be REALLY strong use pyCrypto
> and something like AES-256.
>
> http://www.amk.ca/python/code/crypto
>
> If you just want to make it somewhat hard for someone to decypher
> you can do something like below (sorry I can't remember where I
> found this to attribute to someone):
> import random
> import zlib
> import time
>
> def tinycode(key, text, reverse=False):
>     rand = random.Random(key).randrange
>     if not reverse:
>         text = zlib.compress(text)
>     text = ''.join([chr(ord(elem)^rand(256)) for elem in text])
>     if reverse:
>         text = zlib.decompress(text)
>     return text
>
> def strToHex(aString):
>     hexlist = ["%02X" % ord(x) for x in aString]
>     return ''.join(hexlist)
>
> def HexTostr(hString):
>     res = ""
>     for i in range(len(hString)/2):
>         realIdx = i*2
>         res = res + chr(int(hString[realIdx:realIdx+2],16))
>     return res
>
> if __name__ == "__main__":
>
>     keyStr = "This is a key"
>     #testStr = "which witch had which witches wrist watch abc def ghi"
>
>     testStr=time.strftime("%Y%m%d", time.localtime())
>
>     print "String:", testStr
>     etestStr = tinycode(keyStr, testStr)
>     print "Encrypted string:", etestStr
>     hex=strToHex(etestStr)
>     print "Hex    : ", hex
>     print "Len(hex):", len(hex)
>     nonhex=HexTostr(hex)
>     #testStr = tinycode(keyStr, etestStr, reverse=True)
>     testStr = tinycode(keyStr, nonhex, reverse=True)
>     print "Decrypted string:", testStr
>
> WARNING: THIS IS NOT A STRONG ENCRYPTION ALGORITHM.  It is just a
> nuisance for someone that really wants to decrypt the string. But
> it might work for your application.
>
> -Larry

Thanks Larry! I was looking for something more beautiful but what the
hey, it works!

Harlin