The bitcoin SHA-256 hash function is a cryptographic standard originally designed by the NSA for industrial-strength reliability for secure data communications. The secure hash algorithm is implemented in a variety of widely used security applications and protocols, including SSL, PGP, and SSH. Bitcoin uses SHA-256 for verifying transactions and calculating proof-of-work or proof-of-stake in the mining process.
Cryptographic hash functions are mathematical operations run on digital data; by comparing the computed “hash” to a known and expected hash value, a person can determine the data’s integrity. Computing the hash of a downloaded file and comparing the result to a previously published hash result can show whether the download has been modified or tampered with.
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