java.lang.IllegalArgumentException: badly formated directory string

it is based on invalid format, try to give correct name structure for instance:

new X500Name("C=DE,O=Organiztion");

RSA demo / example

This is the implementation of RSA tutorial given at http://www.javamex.com/tutorials/cryptography/rsa_encryption.shtml with little bit of additions so you can use it right out of the box.

CLASS:  RSAKeyGenerator

Method: void generateKeyPair("<public key file name>","<private key file name>")

CLASS: RSAEncDec

Method: String encrypt("your plane string message", "<location of public key file>")

              [Returns the base64 encoded string that you can send easily]

Method: String decrtpt("<above base64 encoded string>", "<location of private key file>")

              [Returns original plane string message]

For details see "readme.txt" and main() methods avaliable in each class

Download project at : https://github.com/meamit/rsa-demo