IC cracking can be classified into three different methods: semi-invasive MCU cracking, un-invasive IC cracking, and invasive IC cracking. The oldest method in the industry is ultra-violet radiation IC breaking. In the 1970s, attackers used this method to unlock microcontrollers, which was classified as invasive at that time. However, it is now considered semi-invasive as it requires decapsulation of the IC package. This method is effective on most OTP and UV EPROM microcontrollers and can fend off low-cost and low-level MCU cracking.
The process of ultra-violet IC cracking can be separated into two steps: first, locate the security fuse of the IC, and then use ultra-violet radiation to reset the IC to an unprotected state. The design of the security fuse in the IC is usually later than the IC memorizer, but ultra-violet radiation can cover the whole IC.