Reading assignment: Hashing

Blockchain and Bitcoin 101
#1810

1- SHA 256
2- hash functions are almost impossible to brute force because of the sheer number of possible outputs

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#1811

  1. What is the hashing algorithm called used in Bitcoin?
    The bitcoin protocol it uses SHA-256 algorithm

  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    Given the fact that the amount of possible parameters that the hashing function is using, it became almost impossible using the current technology.

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#1812

1. What is the hashing algorithm called used in Bitcoin?
Hashing algorithm used in Bitcoin is SHA-256
SHA – 256 : Secure Hashing algorithm 256
The output will always have a 256 bit length
2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
If you spend your time every second guessing hash functions, you will need to spend the rest of your life to complete it, and most of the time, requiring your next generation to continue the work.

So it is practically infeasible and uneconomical to do so.
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#1813

1: SHA 256
2: SHA-256 is really hard to brute-force because it takes a lot of computational effort and resources. In order to find a collision you need to do approximately 2^256 computations.

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#1814
  1. SHA-256 (Secure Hashing Algorithm - 256 bit)
  2. It’s almost impossible to brute force because even though hash functions are deterministic, they are are also more or less Pre Image Resistant according to the hash algorithm used. In particular the SHA-256 used by the BTC blockchain always generates a fixed 256 bit long output, which changes completely with any slight change of the input. The probability of finding the correct input via brute force 2 by 2 comparison (e.g. taking an input, hashing it and comparing if what you get is the same & repeating the process) in a “normal amount of time” is abysmally low.
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#1815

  1. Bitcoin uses the SHA-256 (Secure Hashing Algorithm 256) hashing algorithm, which always returns outputs 256 bits in length.

  2. SHA-256 is almost impossible to brute force because of the sheer number of potential inputs that could return the desired output. Given that hash functions are deterministic, that means there are 2^256 different possible inputs to hash and compare to brute force the algorithm.

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#1816
  1. Secure Hashing Algorithm 256
  2. There is such a large number of possibilities guessing the correct has combo would take more then several lifetimes.

Read that whole article, understood 1/4th of it. This is getting complex fast… Going to watch some YT videos for a better understanding on the topic.

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#1817
  1. SHA-256
  2. Because due to the amount of possible inputs it would take a very long time (on average 2^255 tries) to break its pre-image resistance.
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#1818

  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?
    because each output is equal to the hashed input concatenated with the hash of a random value that’s been pulled from a distribution with high min-entropy

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#1819

[quote=“ivan, post:1, topic:8422”]

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

Brute force means that you will need to randomly get an input and compare it with the output to get a match. This will take a gagillion years (approx :slightly_smiling_face:)!

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#1820

Watching live YT videos will help indeed, but you will also pick up the rest of the knowledge along the way. Encryption is such a broad topic that some people are studying it their entire lives and still don’t know half of it :stuck_out_tongue:

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#1821

1.Sha 256
2. To crack a hash you would need to randomly guess the correct 256 bit hash which has incredibly low likelihood of happening because of the length of the hash.

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#1822

  1. SHA-256

  2. It is really hard to brute-force because there are too many inputs that are possibilities. Because of the amount of inputs it makes it almost impossible to use brute-force ( or guess ) what the result is.

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#1823
  1. What is the hashing algorithm called used in Bitcoin?
    Bitcoin uses SHA256.
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    The time to break the algorithm with today's computer power would take a lifetime.
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#1824

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

Why is this hashing algorithm really hard (almost impossible) to brute-force?
Pre-Image Resistance makes it extremely impractical to trace an output back to its origin

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#1825

I did spend the night researching hashing, and its a really cool topic. What confused me was hash vs encryption (sha256 vs aes256). At first I thought they where the same, but see they are totally different as a hash can not be reversed with a key.

#1826

True, hash functions have different use case than public key cryptography. :slight_smile: in the course we mostly just touch hash functions but if you want to learn more about cryptography, you should check out the privacy course in the academy.

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#1827

  1. The Bitcoin hashing algo is sha-256

  2. sha-256 is hard to brute-force because it would take
    so long to actually work it is not even worth the
    effort.

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#1828

SHA-256

Brute force means one would need to guess it. So it would take a very very long time to guess it. And very long means many generations, therefore it it unfeasable rather than impossible.

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#1829
  1. SHA-256
  2. It is impossible to brute force because of the SHA-256. If even by luck, an input of one block of the chain has been found out by the hacker; this results in the subsequent blocks hash changing and making it very time consuming to compromise and makes it infeasible.
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