# Questions tagged [hash]

A cryptographic hash algorithm is a function which takes a variable size input and produces a fixed size output. The algorithm makes it difficult to find two inputs with the same output or reconstruct the input from the output.

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### Generate a key with a size bigger than the hash output length/security, is it possible? [duplicate]

Let's suppose I want to generate a 2048-bit key from a hash function with security up to 512-bits (such as Blake2b). I take 4 high-resolution photos, hash them with a hash output length of 512-bits ...
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### Hashing Passwords and Hash Functions

I'm a complete noob. I was reading up on hash functions. So if a bank has its user password's run through a hash function, it'll produce a unique hash for every password right? Thus, even if hackers ...
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### Do proof of work hash function arguments have anything in common?

Some proof of work hashes have a lot of initial zeros. Do the arguments to the hash functions giving these zero containing hashes have anything in common, or are they stochastic? What I am looking ...
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### Understanding intermediate values - SHA2 - 512

I am trying to understand SHA2 - 512 algorithm, so I am following this document which has the intermediate values for the string "abc". At t=0, the values ...
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### Can a collision resistant hash return zero?

Recently, I have been reading the original proof of GCM. It mentioned the properties of "almost universal" and "return zero" for hash function. I wonder if there is a connection ...
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### Will Hashing Multiple Times Be More, Less, Or Similarly Secure As Hashing Once

Will Hashing Multiple Times Be More, Less, Or Similarly Secure As Hashing Once? Flushing out this question: I saw this claim: List item: ...
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