Posted by Jeremy Deuel on 02/17/06 22:06

In article <1140181912.627470.148460@g43g2000cwa.googlegroups.com>,
"Sjoerd" <sjoerder@gmail.com> wrote:

> Jeremy Deuel wrote:
> > Just an Idea:
> > In PHP, passwords for different purposes often are stored plaintext in
> > the source. I often wondered, how this could be prevented.
>
> Nice functions, and not that simple to decrypt.
>
> People already thought about this, and came up with the following:
> XOR "encryption": A bitwise XOR (exclusive or, ^ operator) is done for
> every character of the string. The key is repeated, as in your example.
> The advantage is that encryption and decryption uses the same function:
> Doing a XOR on a string twice will result in the original string.
> ROT-13: Rotate the alphabet with 13 positions: A becomes N, B becomes
> O, etc. Because there are 26 letters in the alphabet, doing a ROT-13
> twice will result in the original string.
>
> Also take a look at str_repeat(), which can repeat the key so that it
> is long enough. You can use the % operator instead of fmod().

Thanks for str_repeat and the % operator. I didn't know them yet..

ROT-13 is not thaaaaaat safe... ;)
XOR would be very interesting, like this one could implement the
vernam-algorithm. How do I implement bitwise operations in PHP?

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