The Natural Philosopher wrote:

I [use] PHP for simple web pages

I know it /is/ possible to write tidy PHP, but to avoid the ancient
kludges requires more self-discipline than most PHP programmers possess

It's not helped by the search engines turning up bad examples for people
to follow, including one recently that recommended encrypting credit
card details using PHP's base64_encode() function!

The page has been pulled now, but I saved a copy ...

http://adslpipe.co.uk/misc/www.ehow.com-7450803-encrypt-card-information-sql-database.pdf