Today, i’m started developing RC4 cipher on PIC18F4550. This cipher was originally developed by Ron Rivest for RSA Security as a trade secret. Eventually, someone posted it to Cypherpunks and sci.crypt Mailing List. Now, RC4 belong to everyone who want to use it🙂 . You may note that the cipher was pretty simple and straightforward. However, since this cipher require large size of RAM for computation. I decided to write the code on PIC18F4550 instead of PIC16F877.
After sitting for more than six hours, finally i was able to code RC4 stream cipher for PIC18F4550. That was an enjoyful moment to me. The code was developed and simulated using MPLAB v8.0 and some PHP script to simulate encryption byte per byte, of course to ensure that everything is under control.
RC4 was the fastest cipher i have ever coded, it reach almost 25 cycles per byte 8) , That was amazing, 8) . See two screenshots below and feel free to use and modify the code under the term of GNU Public License v3.0. Have a nice day and happy coding😀 .