What is SHA-256?
SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function that converts input data of any size into a fixed 256-bit (32-byte) hexadecimal string. It acts as a secure, unique digital fingerprint, widely used for data integrity, digital signatures, and securing blockchains like Bitcoin due to its collision resistance and one-way, irreversible nature.
Key Characteristics
It is computationally infeasible to determine the original input from the resulting hash.
Regardless of input size — a single letter or a huge file — the output is always 256 bits.
A tiny change in the input — even changing one letter — completely alters the hash value, making it ideal for detecting tampering.
It is highly unlikely that two different inputs will produce the same hash value.
Defined in FIPS 180-4, it is a key part of modern security and is used to verify data integrity.
Common Applications
Used to secure block data in blockchains like Bitcoin and Polygon.
Ensures data authenticity and integrity.
Generates checksums to confirm files have not been modified — exactly how OCSA uses it.
Converts passwords into secure hashes for database storage.