Secure combination of PRGs
Secure combination of PRGs
-
Secure combination of PRGs] Let G1, G2 be the deterministic functions which take bit-strings of length “s” as inputs and output bit-strings of length “n”, wheren >> s. undefined Define the functionH(k1,k2)=G1(k1) Å G2(k2) , where k1, k2 Î {0,1}s.undefined
Task: Prove that if eitherG1orG2is a secure PRG, then so is H.
undefined
Note: Your proof may be informal.
undefined
Remark: The function “H” takes two inputs k1andk2, which are used as inputs (seeds) for
the generators (functions) G1andG2, respectively.
SAMPLE ASSIGNMENT
