The Hardware Side of Cryptography

13 May 2008

The Implementation of Caesar Cipher on PIC16F84

Caesar cipher is a classic and simple encryption scheme. It works based on alphabet shifting. Cipher text is generated by shifting plain text by “key” unit which is secret. For example, if shifting key is 2, “A” becoming “C”, “B” becoming “D” and so on. The process is really easy to understand.

Besides software implementation, Caesar Cipher also applicable to programmable embedded hardware such microcontroller. I have coded a program of Caesar Cipher on PIC16F84. The code is shown on Download section. The simulation is done using MPLAB 8.0 from Microchip. Feel free to use it under the term of GPL 3.0 :D . As an example have a look this example:

Example:

  • Plain Text : YOU KNOW, MY BOSS IS A REAL JERK I CAN NOT BELIEVE HE ASSIGNED ME A HELL OF PROJECT
  • Key : 2
  • Cipher Text : AQW MPQY, OA DQUU KU C TGCN LGTM K ECP PQV DGNKGXG JG CUUKIPGF OG C JGNN QH RTQLGEV

Take a look on both two pictures below, it describes you how Plain text procesed into Cipher text.

Plain Text

Cipher Text

This is cipher is really insecure, never use this for sensitive data :) .

RELATED STUFF

Download:
Source Code v1.0
Source Code v1.1
PIC16F84 Datasheet
Mid-Range Reference Manual
MPLAB v8.0

Reference:
Caesar Cipher

Official Website:
- Microchip

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