US Patent 8046571 System-on-a-chip (SoC) security using one-time programmable memories

Apparatus having corresponding methods and computer programs comprise: a processor; a test interface that is in communication with the processor only when the test interface is enabled; a first one-time-programmable (OTP) memory; and a non-volatile memory to store boot code for the processor, wherein when the processor is booted, the boot code causes the processor to test the first OTP memory; wherein the boot code causes the processor to enable the test interface when the first OTP memory has not been programmed; and wherein the boot code causes the processor to disable the test interface when the first OTP memory has been programmed.