An AES implementation on PIC16F877 « The Hardware Side of Cryptography

9 February 2008

An AES implementation on PIC16F877

Filed under: encryption — Tags: AES, encryption, Microcontroller, PIC16F877 — edipermadi @ 2:16 am

Yup, previously i’ve implemented AES (Rijndael) 128 bit using PIC16F84. But you knew that the performance was not so good. Since program size and speed are trade off and limitation of PIC16F84 memory space, i decided to decrease the the performance to fit PIC16F84 memory limit.

Here, i ported the code into PIC16F877 which has larger memory . Of course to speed up the application. By using PIC16F877, i felt much more flexible to rock the microcontroller. As a benchmark, porting the code from PIC16F84 into PIC16F877 will speed up the encryption process by 56% as well as speeding up decryption by 37%.

Speed Benchmark:

Encryption
PIC16F877 : 3834 cycles
PIC16F84 : 7157 cycles
Decryption
PIC16F877 : 5250 cycles
PIC16F84 : 28504 cycles

Today, i woke up till 3 AM just to make a significant progress of this cipher implementation. The new version which is v1.7 has a giant step distance from its predecessor. The latest version (v1.7) requires less memory program and it’s able to do inverse mix column twice faster than the previous version (v1.6). Nice progress huh! .

I will keep modify both of codes to rock the microcontroller and speed up the whole process. If necessary, i will also port the code into higher microcontroller platform such PIC18x. However, the implementation of AES (Rijndael) cipher in this post is intended for performance oriented application. Now, I’m currently developing another version of AES (Rijndael) cipher on PIC16F877 which are AES-192 and AES-256. Keep visiting this blog to get the latest release. Have a nice day !

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