Hashing in Blockchain
Hashing is a key aspect of the Blockchain technology and plays an important role in ensuring the security and integrity of the data stored in the Blockchain. In cryptography, a hash function takes an input (or ‘message’) and returns a fixed-size string of bytes, which is unique for a unique input. This string of bytes is called a hash or a digest.
In Blockchain, hashes are used to link blocks together, creating a chain of blocks, hence the name ‘Blockchain’. Each block in the Blockchain contains a hash of the previous block, forming a secure, tamper-proof chain of transactions. This is achieved by using a secure hash function such as SHA-256, which makes it computationally infeasible to alter the data stored in the previous block without changing its hash. As a result, the integrity of the entire Blockchain is maintained and any attempt to tamper with the data stored in the Blockchain would be immediately noticeable.
Hashing is also used for digital signatures in the Blockchain, which enables secure and verifiable transactions. When a transaction is made, it is signed with the sender’s private key, creating a digital signature. This signature, along with the transaction details, is then hashed, providing a secure and tamper-proof representation of the transaction that can be stored in the Blockchain.
A hash function is a crucial part of the public key cryptography in blockchain technology. It is a process of mapping data of any size to data of fixed size. The Bitcoin network uses the SHA-256 hash function that generates a hash output of 32 bytes (256 bits).
The hash is unique for the message it represents and any modification in the message will result in a different hash value. It is not possible to reconstruct the original message from the hash value. The use of hash functions helps in maintaining the integrity of the data in the blockchain network.