Using formal verification tools (Cadence JasperGold, Synopsys VC Formal) to mathematically prove that hardware bus firewalls cannot be bypassed under any operational condition.
A subtle bug in an RTL state machine or address decoding priority logic could allow a carefully crafted burst transaction to bypass an on-chip firewall. Because hardware bugs cannot be patched after tape-out and fabrication, formal verification is an absolute prerequisite for high-assurance silicon.
We formulate formal security invariants in SystemVerilog Assertions (SVA): proving that for all possible master IDs, address ranges, and interleaving transaction states, no unauthorized master can ever observe or modify data in the cryptographic memory region.
Case studies illustrating how formal property verification discovered subtle corner-case race conditions during simultaneous burst transactions that traditional randomized simulation testbenches failed to detect.