<p><b>Abstract</b>—A widely used bus-encryption microprocessor is vulnerable to a new practical attack. This type of processor decrypts on-the-fly while fetching code and data, which are stored in RAM only in encrypted form. The attack allows easy, unauthorized access to the decrypted memory content.</p>

Bus encryption, cryptography, tamper resistance, secure microprocessor, crypto processor, software protection.

Markus G. Kuhn, "Cipher Instruction Search Attack on the Bus-Encryption Security Microcontroller DS5002FP", IEEE Transactions on Computers, vol. 47, no. , pp. 1153-1157, October 1998, doi:10.1109/12.729797