RSA is an encryption algorithm that was developed by Rivest, Shamir, and Adleman in 1977. The goal was to have a method for transmitting a secret code without having to worry about eavesdropping. As it is an asymmetric encryption algorithm, it can be used in public key crypto systems which are the basis for e-commerce today. My favorite description of how to build a computer that hacks a 1024 bit RSA key likens the task to creating a black hole. Any such computer would have a mass that exceeds the Chandrasekhar Limit.

My original interest in RSA began when I was developing the real time communication protocol for Computer Motion's robotic telesurgery system. While the original test system worked really well without security measures, it would be really BAD if joe-hacker tried to dice somebody's liver with a scalpal. RSA is one of several algorithms that forms the foundation of CMI's security protocol - similar to the Secure Socket Layer (SSL) developed by Netscape. The article Exploring RSA Encryption in OpenSSL goes more in depth on a practical implementation of RSA.

Linux Journal has some requirements on the size of the articles that I write for them. While the article on RSA in OpenSSL covered much of the basics, I really wish that I had the space (and time!) to cover more material. For those who were dissatisfied with the cursory overview presented by the article, here's some more info to allay your appetite.

While the article focused on the practical aspects of an RSA implementation these links will give you a more theoretic background on the subject, as well as point out some more interesting links.

• OpenSSL Home Page A library of encryption algorithms
• Factoring Challenge! Make money factoring composits into prime numbers
• The Primes Page EVERYTHING you wanted to know about primes
• Relative Primes A succinct definition - courtesy of Wikipedia
• Extended Euclidean Algorithm This algorithm finds "Relative Primes"
• Montgomery Multiplication A complicated approach for multiplying two numbers

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