Python crypt/decrypt strings

Question

Is there a lib for this kind of crypt/decrypt in python? I am trying to generate encrypted ascii text which changes on each generation.

If no lib for this, would you please advice a working alternative. Already tried to convert this PHP code to python but I failed.

PHP what I use at the moment:

function keyED($txt,$encrypt_key)
{
    $ctr=0;
    $tmp = "";
    $txt_len=strlen($txt);
    for ($i=0;$i<$txt_len;$i++)
    {
        if ($ctr==strlen($encrypt_key)) $ctr=0;
        $tmp.= substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1);
        $ctr++;
    }
    return $tmp;
}

function encrypt($txt,$key)
{
    srand((double)microtime()*1000000);
    $encrypt_key = md5(rand(0,32000));
    $ctr = 0;
    $tmp = "";
    $txt_len = strlen($txt);
    for ($i=0;$i < $txt_len;$i++)
    {
        if ($ctr==strlen($encrypt_key)) $ctr=0;
        $tmp.= substr($encrypt_key,$ctr,1) . (substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1));
        $ctr++;
    }
    return keyED($tmp,$key);
}

function decrypt($txt,$key)
{
    $txt = keyED($txt,$key);
    $tmp = "";
    $txt_len=strlen($txt);
    for ($i=0;$i<$txt_len;$i++)
    {
        $md5 = substr($txt,$i,1);
        $i++;
        $tmp.= (substr($txt,$i,1) ^ $md5);
    }
    return $tmp;
}

$x = encrypt("test", "123");
echo decrypt($x, "123") // -> "test"

Can you show the Python code you tried to write (that failed)? — David Robinson, Jul 17 '13 at 19:53
Have you checked the [docs...](http://docs.python.org/2/library/crypto.html)? — wflynny, Jul 17 '13 at 19:58

score 1 · Answer 1 · edited May 23 '17 at 11:49

1

NEVER write your own crypto algorithms! There are enough existing ones which have already been reviewed over and over again.

That said, there is an example how to use the AES algorithm with the Python Crypto module in this answer: https://stackoverflow.com/a/12525165

edited May 23 '17 at 11:49

Community

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answered Jul 18 '13 at 22:48

lathspell

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Python crypt/decrypt strings

1 Answers1