Reading assignment: Hashing

Blockchain and Bitcoin 101
#1066
  1. SHA-256
  2. it would be infeasible to use brute-force due to the required computational attempts that would be needed, given the 256 hash and therefore impractical to even attempt.
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#1067

Thanks as always Fabrice

your help is really apreciated

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#1068

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

  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    Becouse the possibility of guessing the result would take a life time. If somehow not lucky…

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#1069
  1. What is the hashing algorithm called used in Bitcoin?
  • SHA256
  1. Why is this hashing algorithm really hard (almost impossible) to brute-force?
  • It will take many generations to solve the equations. And each block will make it many many times more harder.
#1070

you are right. it would be 2^(256-1). thanks

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#1071

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

The hashing algorithm used in Bitcoin is called SHA-256.

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

It is because the possibility of getting it right would take infinite, unless the possibility of luck playing in your way.

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#1072
  1. What is the hashing algorithm called used in Bitcoin?
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
  1. SHA256
  2. An unfathomable number of possibilities makes it unrealistic to attempt.
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#1073

SHA-256

To brute-force a hashing function means to try and guess the input after given a large output. There is no way to do this other than guessing the numbers of the input | concatenated with the other part of the input (nonce?) and then running the hash function on that and hoping it will result in the output we are looking for. There’s no other way to reverse engineer this function. Hence “brute force”.

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#1074

  1. Sha-256

  2. It’s almost impossible to find the input starting from the output. it will take too much time

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#1075

  1. SHA-256

  2. because it will take * 2^128/2 = 2^127 times. 2^127 = 1.7 X 10^38. it might takes a life long of three generations.

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#1076

The nonce has nothing to do with Sha256. The nonce is just a random number that miners add in a block to make sure that the blockhash is low enough (starting with a bunch of zero’s) to get accepted by the network (target depends on the current difficulty)
Miners basically brute force the nonce until the hash of the whole block is low enough.

#1077

SHA-256 (Secure Hashing Algorithm 256)

because of pre-image resistance

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#1078

But here we are not talking about mining. Here we are just talking about brute forcing a Sha256 hash. You need to guess the input of a hash by keep guessing inputs and hashing it until your hash is the same as the one you want to brute force. It’s like trying out every combination of a pin number until you find the correct number.

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#1079

Hashing algoritme used in Bitcoin = SHA256

it is almost imossible to find the input used that has created the output

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#1081

That would be a good assumption. Nice catch. Thanks.

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#1082
  1. What is the hashing algorithm called used in Bitcoin?

SHA-256

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

The number of possibilities and computational effort required, makes it infeasible to even try to brute-force

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#1083

  1. SHA-256

  2. Because guessing the right answer (which is brute forcing) would take so much computing power, that it would take millions of years using current 2020 technology. , I.e. you would need to run too many modern computers, and the resources needed for that are not worth the effort put in (and probably very few actors even possess this kind of computing power today).

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#1084
  • the hashing algorithm used in Bitcoin is sha-256
  • This hashing algorithm is really hard (almost impossible) to brute-force because the probability is against you.
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#1085
  1. SHA-256
  2. Because it is infeasible to determine the input from the output because there are so many options to try (incase of 256 bit, 2^256-1 possible cases that the computer has to try). It could take multiple lifetimes to get to the answer.
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#1086

  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?
    It is almost impossible to brute force, because the options are almost endless and it could take so much time that it doesn’t really matter.

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