15 questions linked to/from Cycles in SHA-256
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### Will rehashing an SHA256 hash continually, eventually produce every possible value? [duplicate]

So let's say you had infinite time and energy. You have a hashed string of some sort. Because you have infinite time and energy, you can produce a collision(or the original value) easily enough. But, ...
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### How long would it take for a sha256 digest loop to reach the original hash or start cycling? [duplicate]

If I started with a sha256 hash such as 3f46fdad8e5d6e04e0612d262b3c03649f4224e04d209295ef7de7dc3ffd78a7 and rehashed it continuously (without salting): i) What ...
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### SHA-2 attempts for a loop [duplicate]

Say I am hashing hashes (taking the hash of a previous hash) for an endless amount of time. How many times would it take, on average, to fall into a loop when using SHA-2 (more specifically SHA-256 ...
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### Are common cryptographic hashes bijective when hashing a single block of the same size as the output?

It's been said that CRC-64 is bijective for a 64-bit block. It the corresponding statement true for typical cryptographic hashes, like MD5, SHA-1, SHA-2 or SHA-3? For example, would SHA-512 be ...
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### Can we use a Cryptographic hash function to generate infinite random numbers?

I have seen that there are PRNG that can generate a specific number of random-numbers. The Mersenne Twister as an example, can generate 2**19937 (if I'm not wrong) but... can we use a cryptographic ...
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### Smallest Guaranteed hash collision cycle length

If I take the sha-256 of an empty string, and apply the hash function $2^{256}!$ times, will I end up with the same hash that I started with? Is the smallest required cycle equal to the LCM of $1$ to ...