tree cd5edaeb27c1e718c16b732e9806c1fab84113d3
parent d1e55dfce66638659a4cec1ba17fc63ba314a519
author Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> 1573208049 +0100
committer Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> 1574346765 +0100

Use large Hamming distance for signature validity

If signature_is_good is 0 (invalid) of 1 (valid), then it's all too easy for
an active physical attacker to turn invalid into valid by flipping a single
bit in RAM, on the bus or in a CPU register.

Use a special value to represent "valid" that can't easily be reached by
flipping a few bits.