Atbash is a simple substitution cipher. Cipher text is obtined by substituting Plain Text into substitution table. In Addition, substitution table is created by reversing the order of bits. Fortunately, Plain text can be obtained by the same method as ciphering. So you don’t need to spent another procedure for deciphering.
The substitution table is shown below.

Anyway, i also wrote a code of Atbash cipher on PIC16F84 microcontroller. I typed and simulated the code using MPLAB 8.0 and works well. Example and screenshots are shown below.
Example:
- Plain Text : YOU KNOW, MY BOSS IS A REAL JERK I CAN NOT BELIEVE HE ASSIGNED ME A HELL OF PROJECT
- Cipher Text : BLF PMLD, NB YLHH RH Z IVZO QVIP R XZM MLG YVORVEV SV ZHHRTMVW NV Z SVOO LU KILQVXG
Plain Text Screenshot

Cipher Text Screenshot

RELATED STUFF
Download:
Source Code | v1.0 | v1.1
PIC16F84 Datasheet
Mid-Range Reference Manual
MPLAB v8.0
Reference:
Atbash Cipher
Official Website:
- Microchip



