Cryptography is in use since ancient times when simpler methods of encryption and decryption were used for the transfer of secret messages. In ancient Greek and Roman times, the techniques used were easily cracked because of the easier patterns used.
Julius Caesar used a similar method. He used to shift each alphabet to left or right by a number of places so that only the recipient would know how to read the text. Any third person who doesn’t know the cipher won’t be able to crack the meaning!
Also, during World War 2, the Germans used to send and receive encrypted messages which played a prominent role in their victory.
Time went past and cryptography improved in its way, or to be more precise it developed to be used in more useful ways. Nowadays, when we talk about cryptography, we generally think of security over the network so that our sensitive information is protected. When we share our private information like passwords, bank details, etc. online or requests something from a server; we need to be safe over the network so that any of the private information is not accessible to any attacker.
Some issues with the cybersecurity are:
When sending information, we need to be sure that it is reaching the correct receivers.
It means that your data should be available and accessible whenever required.
The term means that the sender and the receiver of the information sent should be authorized before the exchange of information.
Both the sides expect to get the information in the most unadulterated form without any noise put by an imposter.
Modern encryption is further of two types:
The sender and receiver have the same key to encrypt and decrypt the message. The sender encrypts the data with the key provided and the receiver decrypts the message using the same key provided to him. However, if the key gets copied or reaches the hand of some imposter, then there is a risk of a privacy breach. The data may be accessed per bit i.e. in a stream way or taking a number of bits at a time, i.e. in the form of a block.
In this type of encryption, the sender has a private key to encrypt the information, and the receiver has a public key to decrypt the data; the advantage of having two keys is that there is no need to share your private key and the public key can be shared to any number of users without it being a secret.
Hence, this is a short brief about what is cryptography and how it works! Hope it helps :)