Can you suggest a simple url-friendly two-way hash/unhash without mcrypt or base64?

I'd like to have a super simple / fast encrypt/decrypt function for non-critical pi开发者_如何转开发eces of data. I'd prefer the encryped string to be url-friendly (bonus points for pure alphanumerics), and no longer than it has to be. Ideally it should have some sort of key or other mechanism to randomize the cipher as well.

Because of server constraints the solution should not use mcrypt. Ideally it should also avoid base64 because of easier decrypting.

Example strings:

sample@email_address.com
shortstring
two words
or three words
555-123-4567
Capitals Possible?

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You will probably have to code it yourself, but a Vigenère cypher on the characters A-Z, a-z, 0-9 should meet your needs.

With careful key generation and a long key (ideally longer than the encrypted text) Vigenère can be secure, but you have to use it very carefully to ensure that.

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There's a wide variety of easy-to-implement ciphers around, such as XTEA. Don't invent your own, or use a trivially broken one like the vigenere cipher. Better yet, don't do this at all - inventing your own cryptosystems is fraught with danger, and if you don't want your users to view the data, you probably shouldn't be sending it to them in the first place.