Does SHA-2 Hashing use a key?

security hash sha2
Marco picture Marco · Aug 29, 2013 · Viewed 7.4k times · Source

From personal knowledge I know SHA-2 hashes are irreversible and do not use a key.

But a person I know has contradicted the above very confidently, I'm now confused and couldn't find the answer I wanted by googling.

Can anyone clear me up on this issue ?

Thanks

Answer

SLaks picture SLaks · Aug 29, 2013

SHA-2, like all hash algorithms, do not use keys.

The definition of a hash function is a map from a single input to an output.

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