On the Subject of the RSA Cipher
Hill Cipher 2.0
A 6 letter word has been encrypted in to 6 numbers in the middle of the screen. Submit this word to disarm the module.
Above these 6 numbers are 2 more numbers labeled N and E. Below that is a flashing cursor that will input anything you type with the keyboard up to 6 letters. The green circular button will submit your input while the red circular button will clear all input made.
Follow the instructions below to get your decrypted word.
Step 1: Get λ(N)
First thing to do is to figure out the 2 prime numbers that were multiplied together to get N. Below is the list of primes used in this module:
11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97
Once, you figure out the 2 primes, then calculate λ(N) using the equation below:
λ(N) = ((P1 - 1) * (P2 - 1)) / GCD(P1 - 1, P2 - 1)
The Greatest Common Denominator (GCD) between 2 numbers can be found using these set of instructions:
- Take the greater of the 2 numbers and modulo it by the smaller number.
- Then take the right number of the previous operation and modulo it by the result of the previous step.
- Repeat step 2 until the result is 0.
- The right number of the operation when the result is 0 is the GCD of the 2 numbers.
Example
N = 1643
P1 = 31
P2 = 53
Calculating GCD
52 % 30 = 22
30 % 22 = 8
22 % 8 = 6
8 % 6 = 2
6 % 2 = 0
GCD(52, 30) = 2
λ(N) = (52 * 30) / 2 = 780