Im looking through old exams for a course in Cryptography and have beaten my head against the wall for a long time on one of the questions:(adsbygoogle = window.adsbygoogle || []).push({});

p = 683 is a prime, p-1 = 2*11*31. What is x = 4^11112 mod p?

When i did chinese remainder theorem on primes 2,11,31 i got that x = 16 mod 682, but so far i have not found a way to use this in determining x mod 683..

Also, when computing discrete logs I have found that one goes from mod p to mod (p-1) alot, why is that?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# A big number modulo a prime

**Physics Forums | Science Articles, Homework Help, Discussion**