Secure Hash Algorithm (SHA) refers to a group of cryptographic hash functions designed to ensure data integrity. SHA converts input data of any size into a fixed-length string of characters, typically represented in hexadecimal format. This process generates a unique output for different inputs, making it nearly impossible to reverse-engineer the original data.SHA is crucial for securing transactions on a blockchain. When a transaction is initiated, it is hashed using SHA, creating a digital fingerprint. This fingerprint is included in the block of transactions and helps to maintain the integrity of the entire chain. If even a small change is made to the transaction data, the SHA output will change dramatically, alerting the network to potential tampering.Different versions of SHA exist, such as SHA-256 or SHA-3, each with varying levels of security and efficiency. SHA-256 is notably used in Bitcoin mining and transaction verification. Overall, SHA plays a fundamental role in ensuring the security and reliability of digital transactions.