Abstract: A method for programming secure data into nonvolatile memory in an IC is disclosed. The method includes steps for loading the secure data into temporary memory, temporarily disabling tester logging functions, and loading the secure data from temporary memory to the nonvolatile memory of the device. Further steps include verifying that the secure data is correctly loaded into the nonvolatile memory of the IC and implementing protection for the programmed secure data to prevent access subsequent to programming. Aspects of the invention include the selection or modification of patterns for programming secure data into nonvolatile memory. Temporary memory containing secure data and/or modified patterns is erased. The programming and protecting steps take place within a single instruction to the TOS so that the user does not regain access to the IC until the secure data is protected within the IC.