What is a standard way to encrypt text in Objective C and decrypt in PHP

This is for an iPhone app which needs to send encrypted data to a web page running php. Symmetric or asymmetric encryption is fi开发者_如何学运维ne. Example code would be greatly appreciated.

Using SSL would be your best bet.

Look up AquaticPrime on the web if you want sample code, includes PHP and Objective-C. This is a package based on SSL for license key generation.

PHP has the Mcrypt library available to be installed which has a number of algorithms. Find a similar library with support which is callable from Objective-C, and give them a try. To avoid having a key on with the program, asymmetric or public key would be more secure (otherwise, it's just giving the password away).

http://www.php.net/manual/en/function.mcrypt-decrypt.php

You can encrypt it on your iPhone app and then decrypt it in PHP. You can pick an algorithm which is supported by both platforms (possibly AES). For the key, you could do something like concatenating the user's password and a long string (salt), the string being hard coded into the iPhone app and the PHP app.

That way, an attacker couldn't decrypt the messages without knowing the user's password, and both the PHP and iPhone app would know this password.