RSA Encryption: Understanding the Algorithm and its Implementation

Project 1 - RSA Encryption
Slide 2
The RSA Algorithm was developed by Ron Rivest , Adil Shamir and Len Adleman at MIT in
1977 and first published in 1978.
It is the most widely accepted and implemented general purpose approach to public key
encryption.
Public Key Encryption means that one algorithm is used for encryption and decryption but
with a pair of keys. One for encryption and one for decryption.
Anyone can encrypt a message using the public key of the receiver and the receiver can
decrypt the message using his private key,
Slide 3
We need to choose two numbers p and q between 6 and 20.
So we choose p=17 and q=11. We can choose any number but it must be a prime number.
We get n = p*q = 17 * 11 = 187.
Slide 4
We calculate m as a product of (p-1)*(q-1) , we get
m= (p-1)*(q-1) = 16 * 10 = 160.
After that we choose a number e that is relatively prime to m and less than m ,
We choose e = 7.
Relatively prime number means that both the number have no other common factor except
1.
Slide 5
The resulting keys (e,n) is my public key.
We get public key , PU = {7,187}.
Public Key is a cryptographic key that is known to everyone and can be used by everyone to
encode and encrypt messages intended for a particular receiver.
The receiver can use its private key to decrypt the message since we use a public key -
private key pair.