RSA is an asymmetric algorithm and is attributed to three people but reading this article will explain who developed the algorithm years earlier. When reading this article, try to understand the section on key generation, encrypting messages, decrypting messages, and signing messages. Most importantly, note the speed of RSA in comparison to DES that was discussed in the section on symmetric key encryption. Also note how attacks such as man-in-the-middle and RSA blinding attacks can be avoided.
RSA can also be used to sign a message. Suppose Alice wishes to send a signed message to Bob. She produces a hash value of the message, encrypts it with her secret key, and attaches it as a "signature" to the message. This signature can only be decrypted with her public key. When Bob receives the signed message, he decrypts the signature with Alice's public key, and compares the resulting hash value with the message's actual hash value. If the two agree, he knows that the author of the message was in possession of Alice's secret key, and that the message has not been tampered with since.