Encrypt file in PHP, decrypt in .Net?

I need to develop an add-on to a PHP web application which encrypts and uploads files to an FTP location.

I then need to write a separate .Net app which will allow a user that has manually downloaded the files fro开发者_JAVA技巧m the FTP location to decrypt the file so that it can then be used locally.

I am aware that there are a large number of different options for encryption in PHP and .Net, but am not sure which - if any - are compatible.

At the moment if someone could just point me in the direction of the methods/functions/libraries to use, I would be very grateful. I don't necessarily need all the code to do it just yet, I can probably work that out myself, although of course, if someone is feeling generous or super helpful and can give me that too, then I'm not going to complain...! :-)

Hoping someone can help and thanks in advance.

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Your best bet is to use a popular algorithm such as RSA, DES, Blowfish, etc.

Many (most?) popular encryption algorithms are supported by the PHP Mcrypt extension