I'm trying to figure out these two questions(adsbygoogle = window.adsbygoogle || []).push({});

1. I have a ciphertext message produced by RSA encryption with key (e,n)=(5,2881) and i'm trying to find the plain text message of

0504 1874 0347 0515 2088 2356 0736 0468

I found the euler-phi function to be 42*66=2772 and found the modular inverse to be 1109 but i'm having trouble finding C^1109(mod2881) for each block of four. can anyone help with this?

2. I'm trying to show that if the encryption exponent 3 is used for the RSA cryptosystem by 3 different people with different moduli, and a plaintext message P encrypted usin each of their keys can be recovered from the resulting 3 ciphertext messages.

I've set it up to the congruences c_i congruent to P^3(mod n_i), i = 1,2,3 but i'm not really sure where to go from here. can anyone help?

thanks

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

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!

# Cryptography questions

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