STM8 microcontrollers use RDP (Readout Protection) to prevent firmware extraction. STM8 decryption bypasses this to recover flash code.

How STM8 RDP Works:
- Level 0: no protection, flash readable via SWIM.
- Level 1: readout disabled, debug blocked. Changing to Level 0 mass-erases flash.
- Level 2: permanent protection, debug disabled forever.

STM8 Decryption Methods:
1. Voltage Glitching: under-voltaging causes RDP check to fail open.
2. Clock Glitching: clock fault injection during protection verification.
3. Optical Decapsulation: removing epoxy, reading flash via microscope.
4. Side-Channel: power analysis during operations.

Recovered firmware can be re-flashed onto new chips, analyzed for bugs, or used for product backup.

STM8 decryption is commonly needed for legacy equipment repair and IP recovery.