Cryptography refers to the long-used technique of using ciphers, where algorithms are used to turn regular messages (plaintext) into nonsense words or numbers (Ciphertext). These messages can be sent via letters or by any other means. The receiver then uses a unique piece of information known as a key, to decrypt the ciphertext back into plaintext.
Although modern-day encryption algorithms led to the formation of cryptanalysis, earlier encryption and decryption were done by hand and the ciphers used were known as ‘classical ciphers’. Not to mention, the inventions of electronic gadgets have increased the difficulties of ciphers.
Encrypting and decrypting without the knowledge of a key is pretty difficult. In blockchain hash functions like SHA-256 are one of the numerous functions that cryptography offers. It is used to secure and safeguard the network operations of Bitcoin (BTC) and other cryptocurrencies.