Table Of Contents
Lab 1: Cryptography
RSA cryptography (named for its inventors Rivest, Shamir, and Adelman) exploits properties and interrelations of humongous numbers, constructed as large powers of huge numbers. Through a neat mathematical trick called modular arithmetic, the computer avoids working with the huge numbers themselves. Let's first learn about modular arithmetic before tackling RSA itself.
The number X (mod Y) is the remainder when X is divided by Y. ( Remember X (mod Y) stands for X modulo Y.)
| For example: | 7 modulo 3 is 1 |
| because: | 7 = 2 * 3 +1, so when you divide 7 by 3, you get a remander of 1. |
Z=X (mod Y)
( This stands for Z equals X modulo Y, which means that Z and X have the same remainder when divided by Y.)
| For example: | 7 = 25 (mod 3) |
| because: | 7 = 2 * 3 + 1 25 = 8 * 3 + 1 |