Register Transfer Level (RTL) locking seeks to prevent intellectual property (IP) theft of a design by locking the RTL description that functions correctly on the application of a key. This paper evaluates the security of a state-of-theart RTL locking scheme using a satisfiability modulo theories (SMT) based algorithm to retrieve the secret key. The attack first obtains the high-level behavior of the locked RTL, and then use an SMT based formulation to find so-called distinguishing input patterns (DIP) 1 . The attack methodology has two main advantages over the gate-level attacks. First, since the attack handles the design at the RTL, the method scales to large designs. Second, the attack does not apply separate unlocking strategies for the combinational and sequential parts of a design; it handles both styles via a unifying abstraction. We demonstrate the attack on locked RTL generated by TAO [1], a state-of-the-art RTL locking solution. Empirical results show that we can partially or completely break designs locked by TAO.

No abstract

No abstract

No abstract

Path-based equivalence checkers (PBECs) have been successfully applied for verification of programmes from diverse domains and from various stages of high-level synthesis. In the case of non-equivalence, PBEC provides very little information which is not sufficient for further investigation of the two programmes being compared by some human expert. In this work, the authors show how a counter-trace (cTrace) can be generated in the case of non-equivalence reported by the PBEC. Using this cTrace, they also present a procedure to find suitable initialisation values for input variables which reveal the non-equivalence (i.e. counterexample) by using off-the-shelf satisfiability modulo theories (SMT) solvers. To aid the human expert, they also show that how they can visualise this cTrace in the control and data-flow graph of the programmes using the graph visualisation software-Graphviz. This counterexample and visual representation of the corresponding cTrace will be helpful in debugging the root cause of the non-equivalence. The experimental results are encouraging.