Cryptography is the science of encrypting information so that only those for whom it is intended can read it. The history of cryptography spans thousands of years. One of the earliest known encryption methods was the Caesar cipher, used by Julius Caesar to protect military messages.

Modern cryptography began to develop in the 20th century with the advent of computers. One of the most important inventions in this field was asymmetric encryption, which allows the use of two keys: one for encryption and the other for decryption. This made secure information exchange on the internet possible.