Discrete Math The first step in all publickey cryptosystems

Discrete Math

The first step in all public-key cryptosystems is to convert the English-language mes- sage into a number, M . This is typically done with the A S C I I code. In this problem, we use a simpler method.

We write our messages using only the 26 uppercase letters. We use 01 to stand for A, 02 to stand for B, etc., and 26 to stand for Z. The word LOVE would be rendered as 12152205 in this encoding. (This is the same method as in Exercise 45.6.)

Suppose Bob’s RSA public key is .n; e/ D .328419349; 220037467/. To encrypt the word LOVE, Alice calculates

12152205220037467 mod 328419349 D 76010536

and sends 76010536 to Bob.
Alice encrypts one more word to Bob. Their encryption is as follows:

18035306
Decrypt the word

Thanks!

Solution

Descrypted Data=c(power d) mod n

where c is encrypted Data

d=private key

n=public key