Introduction - If you have any usage issues, please Google them yourself
In cryptography, RSA (which stands for Rivest, Shamir and Adleman who first publicly described it see below) is an algorithm for public-key cryptography. It is the first algorithm known to be suitable for signing as well as encryption, and one of the first great advances in public key cryptography. RSA is widely used in electronic commerce protocols, and is believed to be secure given sufficiently long keys and the use of up-to-date implementations.