## RSA

RSA is a cryptography algorithm. As with all methods of cryptography, the RSA is mathematical in nature and is for public-key cryptography. The algorithm gets its name from the surnames of its inventors, namely, Ron Rivest, Adi Shamir and Leonard Adleman.

RSA involves using a public key and a private key. The public key is available to all and can be used to encrypt messages. The private key on the other hand is kept secret and is used to de-encrypt the encrypted message. Therefore, in terms of cryptography, Alice uses the public key to send messages to Bob, who in turn possesses the private key. Although both of them have the private key to decipher each others messages. That is, the algorithm finds the product of two large prime numbers and then performs another set of subroutines to derive a set of two numbers constituting the public key and the private key. After the construction of these keys, the original prime numbers can be tossed out because they are no longer indispensable.

A bonus with RSA is, it offers authentication between Alice and Bob, by using a private key to encrypt a digital certificate rather than just encrypting messages. That way, when Bob receives it, he can use Alice’s public key to decrypt it.

RSA is computationally expensive, hence other algorithms are employed to simplify the process of encryption, but this will make it easier for Eve to intercept. (Eve in cryptography terms is an eavesdropper).

Branch Prediction Attacks and the like are employed to break a given RSA encryption, although, the probability of their success depends on the RSA key and its complexity.

It also finds its way into hardware implementation. As RSA chips are increasing in speed, encryption and decryption add less overhead to the operation.

### Reference

What is RSA? – A definition from whatis.com
http://whatis.com
Search Security
http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci214273,00.html
Wikipedia
http://en.wikipedia.org/wiki/RSA