RSA Cryptology

What is RSA Cryptography?

Do you remember what cryptography is? It is the study of how to write ciphers, or secret messages. RSA Cryptography is one of the ways that you can write a cipher.

What does RSA stand for?

RSA comes for the names of the people who invented it. They were Rivest, Shamir, and Adleman.

How does RSA Cryptography work?

RSA Cryptography uses mathematical formulas to change your message into a cipher. Very large primes are needed for these formulas. After choosing primes, an encryption key and a decryption key are chosen. These "keys" are numbers that let you change a message to a cipher or a cipher to a message.

What do I need a computer for?

The math behind RSA Cryptography uses very large numbers. Usually the primes chosen are hundreds of digits long. You will use much smaller primes in this module. Even small primes are too large to calculate the math for. All the math is done in mod. Mod is a concept you may not be familiar with. It means that you always take your answer, divide it by a number, and keep the remainder as your answer. Although you probably know how to divide and how remainders work, these numbers are very large and the math takes a lot of time.

Why do I care?

RSA Cryptography is a principle used a lot in your life. Do you know someone who orders things on the internet? When sensitive information is sent on the internet, cryptography is used to keep the wrong people from getting that information. RSA Cryptography is used both for encryption and something called digital signatures. A digital signature is how your computer signs its name. It lets people know that something through the internet really comes from you.

Is RSA Cryptography safe?

RSA Cryptography is relatively secure. It is not easy to break. This is because RSA Cryptography uses numbers that are very large. Remember the large prime you looked at in the prime module earlier? RSA Cryptography uses primes that long or longer! These large numbers determine your keys. Unless a person has both the keys or can figure out the very large numbers then your message will probably stay secret.

What else do I need to know about RSA Cryptography?

RSA Cryptography is special. It lets me make my encryption key and another number called N public and keeps my messages safe. So what? If I make these two numbers public, then anyone can use them. This means that anyone can write to me in secret. The person that wrote to me still can't break my ciphers and read my messages. However, someone else who looks at what this person wrote to me won't know what it means either. This way a message stays safe on its way to me.

1. introduction

3. start