How are you? By Allah's grace, I'm doing very well.

Cryptography is the backbone of blockchains and cryptocurrencies. Without it, decentralized networks would not be able to operate securely, verify transactions, and protect user assets. The two fundamental cryptographic tools used in blockchains are hashing and public-private key pairs.

1. Hashing

Hashing is a mathematical process in which input data is converted into a fixed-length, unique, and easily verifiable output, called a hash or cryptographic fingerprint. It is virtually impossible to recover the original data (input) from a hash. This process only works in one direction. The same hash will always be output for the same input. Even the slightest change in the input (e.g., a single letter or comma) completely changes the output hash. Each block contains the hash of its previous block. If someone tries to change the data in a block in the middle of the chain, the hash of that block will change. Since the old hash is recorded in the next block, the chain connection will be broken. In this way, hashing ensures the security of the entire blockchain. There is no need to download the entire block to verify billions of transactions or a huge block of data. Instead, it is enough to verify only its small hash. In a network like Bitcoin, miners have to work to create a specific hash, which ensures the consensus of the network.

2. Public-Private Key Pair

A public-private key pair is a pair of two cryptographic codes that are mathematically related to each other. This pair ensures the digital identity of the user and the authorization of transactions on the blockchain network. The private key is the secret password or master key of your wallet. Only using this key can you access your crypto assets and digitally sign transactions. The private key must be kept secret. If it is leaked, anyone can steal your assets. And the mathematical basis is usually a large, random number. The public key is mathematically derived from the private key and forms the basis of your wallet address. It is shared publicly on the network. When someone else wants to send you cryptocurrency, they use your public address. The network uses this public key to verify that the digital signature created by your private key is valid.

Digital Signature

When you initiate a transaction, the transaction is signed using your private key. This signature proves that you authorized the transaction and ensures that the transaction has not been altered during the process (integrity). This pair is designed in such a way that you cannot derive the private key from the public key, which forms the basis of blockchain-based security and ownership. Today's discussion concludes here. I hope you've found it interesting. Please share your thoughts on today's topic. Prayers for everyone. May everyone be well.