RSA Cryptography methods have been standardized across all development platforms for many years now.
Every platform I have worked on (Linux, OSX, MS) has basic usable methods of encrypting and decrypting RSA encrypted information. This would lead a programmer to believe that you can pass that encrypted data between environments and systems. Much to my dismay, I have found out this is not actually the case.
Read this MSDN article that explains how since version 1, the MS .NET platform actually passes RSA encrypted data around backwards.
http://blogs.msdn.com/shawnfa/archive/2005/12/05/500144.aspx