On the security of MQ_DRBG
MQ—DRBG is a pseudorandom number bit generator proposed for international standardization by the French national organization for Standardization (AFNOR). It makes use of a specific instantiation of a one-way function S : F2 → F 2 based on quadratic multivariate polynomials. We describe two methods for constructing function S, satisfying requirements of the proposed draft, but having less security level.