Abstract
This paper deals with the phase-shift fault analysis
of stream cipher Grain v1. We assume that the attacker is able
to desynchronize the linear and nonlinear registers of the cipher
during the keystream generation phase by either forcing one of
the registers to clock one more time, while the other register is not
clocked, or by preventing one of the registers from clocking, while
the other register is clocked. Using this technique, we are able to
obtain the full inner state of the cipher in reasonable time (under
12 hours on a single PC) by using 150 bits of unfaulted keystream,
600 bits of faulted keystreams and by correctly guessing 28 bits
of the linear register.
Go to article