Hi. On Sun, 16 Sep 2007, Joachim Strmbergson wrote: > One could add test functionality that checks the randomness of the > initial SRAM state after power on. But somehow I don't think a good test > suite and extremely low cost devices (for example RFID chips) are very > compatible concepts.
One can test a source of randomness by checking statistics of its few samples, but if I understand the article correctly, in case of SRAM each cell behaves as an independent source of randomness: some bits are almost always stuck at fixed values while others have some freedom. In this case it is pointless to do tests using initial SRAM state after a single power on, because to gather a few samples from each source one needs to repeatedly reset the device. Applying statistical tests to a hash of the whole SRAM does not make much sense either -- a good hash function will give statistically good results even if you give it a counter. -- Regards, ASK --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]