Cryptography is a method of using encryption and decryption to secure communication in the presence of third parties with ill intent—that is, third parties who want to steal your data or eavesdrop on your conversation. Cryptography uses computational algorithms such as SHA-256, which is the hashing algorithm that Bitcoin uses; a public key, which is like a digital identity of the user shared with everyone; and a private key, which is a digital signature of the user that is kept hidden.

Cryptography in Bitcoin Transactions

In a normal bitcoin transaction, first, there are the transaction details: whom you want to send the bitcoins to and how many bitcoins you want to send. Then the information is passed through a hashing algorithm. Bitcoin uses the SHA-256 algorithm. The output is then passed through a signature algorithm with the user’s private key, used to uniquely identify the user. The digitally signed output is then distributed across the network for other users to verify. This is done by using the sender’s public key.

The users who check the transaction to see whether it’s valid or not are known as miners. After this is done, the transaction and several others are added to the blockchain, where the details cannot be changed. The SHA-256 algorithm looks something like in the image below.

You can see how complicated it is, meaning it’s safe to say that the encryption is very difficult to hack.