RSA encryption

RSA Algorithm

The idea for a public-private key cryptosystem originally came from Whitfield Diffie and Martin Hellman in 1976, when they published the concept. The original algorithm they created used a shared key created from a number, modulo a prime number. Over the years, many people worked on trying to create a function that would be easy to do one way, but very hard to invert (do it the other way). The final algorithm was completed when, one night, Ron Rivest had a “good deal” of wine at a Passover dinner. Rivest then went home and spent the night finalizing the formula and had the paper to present it almost ready by the next day.

               How does it work? RSA uses a public key and a private key to encrypt data. The public key is meant to be public and to be spread and known by anyone wanting to send a message to the owner of the public key. The private key is mathematically linked to the public key and allows a message encrypted using the public key to be decrypted by using the private key that it is linked with. The keys for RSA encryption are created by using math on two distinct prime numbers to mathematically calculate the private and public keys.

               What makes this special? RSA encryption allows us to encrypt data and ensure that only the user holding the private key can decrypt it. It also allows us to be able to spread around a public key so that someone that wants to send a message us able to encrypt it and ensure that it’s for our eyes only. The algorithm is also designed to be very easy to encrypt data, but trying to crack the encryption is very hard without the private key, giving the users greater security.

               Could we do this algorithm manually? Yes, you could do the math behind calculating the keys and encrypting/ decrypting manually, but the math would be very long and tedious. For the keys to be as secure as possible, you must select large prime numbers and this would be very difficult for a human to do the calculations, so they are almost exclusively done by computers.

               I’m currently very excited to read chapter 6 of “The Pattern on the Stone” because that chapter talks about “secret codes”. I’m hoping they cover a little about RSA type encryption because it’s very commonly used today. I had lunch with Eugene Vasserman, a professor at KSU about a year ago and when handing me his business card, he pointed out the PGP encryption public key on the back of the card. by using this PGP public key, I could encrypt a message that would be just for Prof. Vasserman, much like RSA.

               A video I would recommend watching to get more information about the math behind the RSA algorithm is Here: https://www.youtube.com/watch?v=wXB-V_Keiu8. This video is from Khan Academy and helps to explain the math and reasoning behind the way it encrypts data and why we encrypt data using RSA instead of having a shared private key between two people so that they may share messages. The video uses the example of a bank sending messages, and if the bank had to have a specific key for each member, it would have too many keys to keep track of, but if it can have one key to decrypt all messages it receives, this allows the bank to communicate much more effectively. I would highly recommend checking out the video for a great explanation, and maybe searching YouTube for other videos to explain RSA encryption in more depth.