SHA-256

SHA-256, which stands for Secure Hash Algorithm 256-bit, is one of the members of the SHA-2 (Secure Hash Algorithm 2) family of cryptographic hash functions. It is a widely used and respected cryptographic hash function designed to take an input (often referred to as a "message") and produce a fixed-size 256-bit (32-byte) hash value. SHA-256 is known for its security and resistance to collision attacks.

SHA-256 always produces a 256-bit (32-byte) hash value, regardless of the size of the input data. SHA-256 is considered a cryptographic hash function, meaning it is designed to provide a high level of security. It is resistant to preimage attacks, second preimage attacks, and collision attacks, making it suitable for various security-critical applications.

A given input will consistently produce the same SHA-256 hash value, ensuring predictability and consistency. A small change in the input data results in a significantly different hash value. This property ensures that similar inputs produce very dissimilar hash values.

Common Uses:

Password Hashing: SHA-256 is often used to securely hash user passwords for storage. It provides a one-way transformation of passwords, making it difficult for attackers to reverse-engineer the original passwords from the hash values.
Data Integrity: SHA-256 is used to verify the integrity of data during transmission. By comparing the hash of received data with a precomputed hash, it's possible to check if the data has been tampered with.
Digital Signatures: SHA-256 is a component of various digital signature algorithms, including those used in secure communication and public key infrastructure (PKI).
Blockchain and Cryptocurrencies: SHA-256 is extensively used in blockchain technologies and cryptocurrencies like Bitcoin to create secure and immutable transaction records.
Secure File Verification: SHA-256 can be used to verify the authenticity and integrity of downloaded files or software by comparing the computed hash with a trusted hash value provided by the source.