Find the urls below for DSE,SDES,RC5:
http://www.codeproject.com/Articles/19538/Encrypt-Decrypt-String-using-DES-in-C
http://www.codeproject.com/Articles/91628/Simplified-version-of-the-DES-Data-Encryption-Stan
http://www.codeproject.com/Articles/22518/Encryption-with-RC-Algorithm