ISSC 266 APUS RSA Encryption Algorithm Exercise

RSA is a common algorithm used to generate Asymmetric keys. Let’s look at an example using two small prime numbers.

Let p = 3 (The 1st prime number)

Let q = 11 (The 2nd prime number)

Now compute N = p X q = 33

Compute z = (p -1)(q-1) = (3 – 1)(11 – 1) = 20

Now pick a number e such that 1 < e < z (e has to be prime)

Pick E = 7

Now compute

(D x E) mod Z ) = 1 (Pick some number d). An example for d = 3

(3 x 7) mod 20 = 1 (Satisfies the equation)

The keys are:

               (D, N)

               (E, N)

And in our case

               Encryption Key = (3, 33)

               Decryption Key = (7, 33)

Now for this discussion, you are going to use two prime number p and q and find the following

N

Z

D

1. Now PICK E
2. R