What is cryptography?

The study of secure communications techniques that allow only the sender and intended recipient of a message to read its contents is known as cryptography. The word kryptos comes from the Greek word meaning "hidden." It's closely linked to encryption, which is the process of scrambling plain text into ciphertext and then back again when it's received. In addition, cryptography includes techniques such as microdots and merging to obfuscate information in photographs. Ancient Egyptians were known to apply these techniques in complicated hieroglyphics, and one of the first modern ciphers is credited to Roman Emperor Julius Caesar.

Encrypting and decrypting email and other plain-text messages is the most prevalent usage of cryptography when transporting electronic data. The symmetric or "secret key" approach is the most basic method. Data is encrypted with a secret key, and the encoded message and secret key are then delivered to the recipient for decoding. What is the issue? A third party has all they need to decrypt and read the message if it is intercepted. Cryptologists invented the asymmetric or "public key" scheme to address this problem. Every user has two keys in this case: one public and one private. Senders encrypt the message and transmit it along after requesting the recipient's public key. When the message is delivered, only the private key of a recipient will decode it, which means, that theft is pointless without the corresponding private key.

In general, there are three types of cryptographic techniques used:

-        Symmetric-key cryptography

-        Hash functions

-        Public key cryptography

A symmetric-key cryptography is when a single key is shared by both the sender and the receiver. The sender encrypts plaintext and sends the cipher text to the receiver using this key. The receiver, on the other hand, uses the same key to decrypt the message and retrieve the plain text.

Hash functions are when algorithm does not use a key. The plain text is hashed with a fixed-length hash value that prevents the plain text's contents from being recovered. Many operating systems also employ hash algorithms to secure passwords.

Public key cryptography is the most revolutionary concept of the last 300 to 400 years. Two related keys (public and private key) are utilized in public-key cryptography. The public key can be freely transmitted, but the private key that goes with it must be kept secret. The public key is used for encryption, whereas the private key is utilized for decryption.

Bitcoin and many other cryptocurrencies are using a technology of public-private key encryption. This removes the necessity for a middleman.