US Patent 10404463 Cryptographic ASIC with self-verifying unique internal identifier

A cryptographic ASIC and method for autonomously storing a unique internal identifier into a one-time programmable memory in isolation, by a foundry or a user. When later powered on, the ASIC calculates the value of the unique internal identifier from a predetermined input and compares the calculated identifier value to the stored identifier value. A match indicates the stored value is valid, while a mismatch indicates the stored value is invalid, whether due to natural memory component aging or damage by unauthorized access attempts. The ASIC may compare the calculated identifier to another copy or copies of the stored identifier, and disregard unreliable copies of the stored identifier. The ASIC may compare multiple copies of the stored identifier in a voting scheme to determine their validity. The confirmed valid lifetime of the ASIC thus extends far beyond the useful lifetime of a single copy of the stored identifier.