Experimental and Timing Analysis Comparison of FPGA Trivium Implementations and their Vulnerability to Clock Fault Injection

The security of cryptocircuits is today threatened not only by attacks on algorithms but also, and above all, by attacks on the circuit implementations themselves. These are known as side channel attacks. One variety is the Active Fault Analysis attack, that can make a circuit vulnerable by changing its behavior in a certain way. This article presents an experimental fault insertion attack on an FPGA implementation of the Trivium stream cipher. It also compares the faults introduced with the faults expected after a timing analysis. The results show that this implementation is vulnerable to such attacks, and also that it is not possible to estimate the position of the inserted faults by means of timing analysis.