Reading assignment: Hashing

Blockchain and Bitcoin 101
#826

1.sha 256 algorithm

  1. Virtually impossible computations. It’s hard to brute force as each input has it’s own Hash.
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#827

1- SHA256: Secure Hashing Algorithm
2- Determining the original input from the hash is almost impossible because for someone to find out would have to take a guess and hash that guess. Then see if it’s the same as the hash of the original input he/she was trying to find out. In average, that would take the person around 2^127 times. That’s a huge number!

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#828

What is the hashing algorithm called used in Bitcoin?
SHA-256

Why is this hashing algorithm really hard (almost impossible) to brute-force?
Because it is a one-way function where the output length is the same no matter the size of the inputs.

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#829
  1. SHA-256
  2. SHA-256 is a secure hashing algorithm that makes unfeasible to determine the original input (Pre-Imagine Resistance) with small chances of 2 values have the same input (Collision Resistance)
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#830
  1. SHA-256 (Secure Hashing Algorithm 256)
  2. Identifying the input based on the number of possible outputs, makes the correct value infeasible to obtain, but not impossible.
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#831

1. What is the hashing algorithm called used in Bitcoin?

  • Bitcoin uses SHA-256.

2. Why is this hashing algorithm really hard (almost impossible) to brute-force?

  • Because it would take someone more than a lifetime finding the answer which is not worth doing it.
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#832

bitcoin uses SHA 256

Because it would take to long

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#833
  1. SHA-256 (Secure Hashing Algorithm 256)
  2. Its temporarily Impractical
    .Number of computational possibilities is so high with a 256 hash that it would make brute
    forcing it feasible.
    .Entropy - there is no dependency on luck.
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#834
  1. What is the hashing algorithm called used in Bitcoin? - sha-256
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force? The number is so large it would take years to compute.
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#835
  1. What is the hashing algorithm called used in Bitcoin?

The algorithm is SHA-256 (256 bit Secure Hash Algorithm), which always produces a 64-byte hexadecimal character string regardless of the size of the input text.

  1. Why is this hashing algorithm really hard (almost impossible) to brute-force?

The algorithm is almost impossible to brute-force because while the hash algorithm is deterministic (the same input always produces the same hash), it is impossible to work backwards and get the original input by decoding the hash. The only method available for finding the original input is by using the brute-force method, which means creating a random input, hashing it, comparing the output with the target hash and repeating it until you find a match.

There is an infinitesimally small probability that someone might generate an input that produces the same hash as the target hash. Since the hash is 64 characters with each character having one of 16 possible values, that means there is a total of 16^64 = 1.16x10^77 hashes. While this is a large number, it is still finite, while the number of possible inputs is infinite… This means there’s a small chance that 2 different inputs from a pool of infinite possibilities might produce the same hash. Because of this, there is no guarantee that a randomly generated input will match the original input.

A good cryptographic hash function meets the following requirements:

  1. The same input should always produce the same output (deterministic)
  2. It shouldn’t require too much computation to calculate the hash (quick computation)
  3. If you have a particular hash, you shouldn’t be able to invent a message with the same hash (preimage resistance).
  4. If you change even a tiny bit of the input, it should have an entirely different hash.
  5. Even though there are collisions, it should not be easy to find them (collision resistance).

SHA256 meets all of these conditions, which makes it ideal for making Bitcoin addresses and transactions secure.

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#836
  1. What is the hashing algorithm called used in Bitcoin?
    Secure Hashing Algorithm 256.
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    Hashing encrypts an input, so breaking that encryption in order to get the same output would be close to impossible and take too long. Barring hacking tools of course.
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#837

1)sha-256
2)there are too many possibilities out there (reminds me of playing lotto, just even more difficult with many more possibilities: extremely difficult to win with all the numbers right - and if you do, it was pure luck)

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#838

SHA-256

Because one change in the input results in a huge change in the hash, so if you were randomly typing in hashes, the output would also pretty much be random. And because there is only one hash (without any crashes) you will be tryinig forever to guess the right one.

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#839
  1. What is the hashing algorithm called used in Bitcoin?
    SHA256
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    It is not impossible but unfeasible…which means that you find out the original input (in avg scenario) after 2^128/2 = 2^127 times…
#840
  1. What is the hashing algorithm called used in Bitcoin?
    SHA-256
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    SHA-256 has very high min-entropy which means guessing a random number would be useless and the brute force method would literally take generations of light speed work to get the one hash youre looking for.
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#841

  1. SHA-256

  2. The sheer number of possible hashes makes stumbling upon a random input that matches a hash nearly impossible (when you have high min-entropy). Pre-image resistance.

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#842
  1. SHA256
  2. Because it takes years to crack a huge combinations of number. you need a powerful computing power to crack it.
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#843
  1. Sha-256
  2. It is extremely hard because there it would take an infinite amount of time to guess the input (required to obtain a specific output), by which time the whole network has moved on, verified and moved to next blocks, resulting in the tampered blocks being ignored.
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#844
  1. What is the hashing algorithm called used in Bitcoin?
  • Secure Hashing Algorithm 256
  1. Why is this hashing algorithm really hard (almost impossible) to brute-force?
  • SHA-256 has 2^256 possibilities, thus highly infeasible to find the right datastring.
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#845

  1. SHA256

  2. Computational possibilities are very highly and highly infeasible as it will lot of effort and resources.

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