Georgi Guninski on Tue, 27 Apr 2021 11:10:10 +0200 |
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Finding n mod p^(D-1) given A=g^n mod p^D |
We asked this on mathoverlow [1], but didn't get answer. Let p be prime and n,g,D integers. Let A=g^n mod p^D Let dlog(p,g,A,D)=log(A+O(p^D))/log(g+O(p^D)). Conjecture 1: dlog(p,g,A,D) mod p^(D-1) = n mod p^(D-1) dlog is efficiently computable. We verified it with hundreds of large tuples (p,g,D,n). It is also related to the discrete logarithm of A in base g modulo p^D. Is the conjecture true? [1]: https://mathoverflow.net/questions/391223/p-adic-logarithms-with-fixed-precision Code: /* discrete logarithm modulo p^(D-1) A=g^n mod p^D dlog(p,g,A,D) mod p^(D-1) = n mod p^(D-1) Author Georgi Guninski */ { dlog1(p,g,a,D=2)=lift(log(lift(a)+O(p^D))/log(lift(g)+O(p^D))); } { tt()= D=3; setrand(1); p=nextprime(10^18);X0=random(p^D);g=Mod(2,p^D);a=g^X0; X1=dlog1(p,g,a,D); \\print(X1,X0); print([(X1-X0)%p^(D-1)]); } tt()