Method and apparatus for protecting designs in SRAM-based programmable logic devices and the like

摘要

Use of an electronic design in a configurable device is controlled by a secure device. The configurable device includes an authorization code generator having a sequence generator and an encryption core implementing an encryption algorithm. The secure device uses the same sequence generator and encryption core in its own authorization code generator. The sequence generators in the configurable device and secure device generate identical streams of values that are encrypted using the encryption algorithm. The encrypted values are compared in the configurable device by a comparator. When the streams of encrypted values are not identical, the electronic design is prevented from operating. Where the period of the sequence generated by the sequence generators is long, such as 2⁶⁴, the output of the encryption cores will contain that many different encrypted values, a substantial amount of highly randomized output used as authorization code for the protection of the electronic design.