What is blinding with a SHA256() or similar cryptographic hash function?
What applications does it have?
An answer to a recent question briefly mentioned "Consider blinding before calling an external function [such as] SHA256()". ( https://security.stackexchange.com/questions/246209/is-it-safe-to-publish-the-password-hashes-from-my-sha256-md5-custom-password-h/246275#246275 )
The Wikipedia article "blinding (cryptography)" currently mentions several different types of blinding, including asymmetric encryption, asymmetric digital signatures, and the one-time pad (a kind of symmetric encryption), but never mentions hash functions. Most applications in that article involved tweaking the plaintext slightly, then running the tweaked plaintext through some (untrusted) function to get some intermediate output, then untweaking to get the final output, in such a way that we get the same final output without the tweaking and untweaking, but without handing over plaintext to the (untrusted) function. Does SHA256() support such tweaking and untweaking? Whether or not it does, what is the proper approach to blinding with SHA256() or other cryptographic hash functions?