what is a RSA encryption ??

what is a RSA encryption ??

RSA : - Rivest-Shamir-Adleman (these are the name of RSA inventors.)

RSA is a encryption algorithm which is used to send message securely in the internet.RSA is a public key algorithm widely used for secure data transmission.In public key algorithm we used two keys for data transmission : one is public and another is private key.We use public key for data encryption and private key for data decryption.
 RSA is based on the principle that it is easy to multiply large numbers, but factoring large numbers is very difficult.

In RSA, the public key is generated by multiplying two large prime numbers and  together, and the private key is generated through a different process involving  and . A user can then distribute his public key , and anyone wishing to send the user a message would encrypt their message using the public key.

Algorithm of RSA :-

1. Choose two large prime numbers P and Q such that P is not equals of Q.
2. Calculate N which is N=P*q.
3. Choose E(public key) such that E is not a factor of (P-1) and (Q-1).
4. Choose D(private key) such that (D*E)mod(P-1)(Q-1)=1.
5. Cipher text(C.T) =(P.T)^EmodN.
6. Plain text(P.T)=(C.T)^dmodN.

read in Wikipedia