Reading assignment: Hashing

Blockchain and Bitcoin 101
#2030
  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 different possibilities is a really large number that makes it an extremely long time to compute.
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#2031
  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 input has its own unique hash output. In order for you to use the brute force method, you would have to randomly pick input values, hash it and then compare it with the target hash until you get to the correct output hash. Because there are is such a wide range of output hash options, it would take forever to find a match.
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#2032
  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 numbers are too large to manipulate would take a very long time making it not practical.
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#2033
  1. SHA 256
  2. It is almost impossible because at average you find the same hash in the middle. Then you have to compare 1.7 * 10^23 hash. It takes lot of time and computational power.
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#2034

  1. sha 256

  2. the number of possibilities with sha 256 is so large it would take many lifetimes to break ( hence nearly impossible )

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#2035
  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?

There are so many possibilities for outputs when it comes to trying to brute-force Bitcoin’s hashing algorithm that it would take forever - or never happen at all.

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#2036

sha-256
too many posibilities

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#2037

1.) The hashing algorithm used in Bitcoin Is SHA- 256. It is an algorithm where any size input can be entered and the output will always be a fixed 256 bit length.

2.) SHA- 256 is almost impossible to brute- force because it would take such a long time that it makes it infeasible. Yet it is possible it would be highly unlikely due to the large number of possible inputs. The input would have to be chosen at random then compare to the output until a match was found. This makes it ideal for cryptography.

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#2038

The hashing algorithm used for bitcoin is SHA 256
The hashing algorithm is almost impossible to to brute force because it is Pre-Image Resistant

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#2039
  • What is the hashing algorithm called used in Bitcoin?
    SHA-256
  • Why is this hashing algorithm really hard (almost impossible) to brute-force?
    The time taken to be able to brute force the algorithm does not make it a viable option for use.
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#2040

  1. What is the hashing algorithm called used in Bitcoin?
    -SHA 256 ( Secure Hashing Algorithm 256 )

  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    -brute force means you pick a random number and hash it and compare it with target hash now this method can work if you have less data to compare here in SHA 256 you can have three possibility first you randomly guess the right answer at the very beginning , or you find it at the end which would take 2^128 - 1 tries or you find it somewhere in between 1 to 2^128 tries and that is a long long number to even write down or read . so if anyone try brute-force method to crack the hash to its original value it would take hundreds of years may be even more thus it is almost impossible .

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#2041
  1. What is the hashing algorithm called used in Bitcoin?

Secure Hashing Algorithm 256 (SHA256) this is the one used by bitcoin but there are others that could be utilised.

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

its not the fact that it is almost impossible to brute force in this instance it is the amount of time that it would take to find an identical hash to the hash that has been generated by the SHA256 algorithm for example hash’s are generated on the data input if the data was for example “the sky is red” it would have a unique string of characters and it would take such a long time to decipher, meaning the purpose of brute forcing wouldn’t be achieved because another hash would likely have already been created in the blockchain.

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#2042

2^128/2 = 2^127 times
Why does this not equal 2^64?
I was reading about the greatest common factor and they do simply reduce the power by (1) but don’t if that is done don’t you have to divide the numerator by 2 as well?

#2043

I think I get it. It is really 2 to the power of 128 minus one power of 2. Right?

#2044

Its because the formula is read as (2^128)/2 and not 2^(128/2) :slight_smile:

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#2045
  1. The hashing algorithm used by Bitcoin is SHA-256.
  2. The SHA-256 hashing algorithm is hard to brute-force because it takes such a long time to find a match, up to 2^127 times.
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#2046

  1. SHA - 256

  2. You have to pick a random input calculate and repeat, this takes a long time unless you are very lucky and guess the right input

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#2047

Sha-256

I would take an impossible amount of time

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#2048
  1. Shaw - 256
  2. The number of inputs can be of any length, but the output is always a fixed amount. Moving backwards from the output to the input is realistically so time consuming that it would take too long to be practical in anyone’s lifetime.
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#2049
  1. Secure Hashing Algorithm 256- SHA-256
  2. A cryptographic Hashfunction needs to be pre-image-resistant, meaning that if you have a hashfunction H(A), it’s infeasible to determine the input A. The only way to determine the input would be to try every possible input and comparing the generated hashes to the desired one (i.e. brute forcing). With an 256 bit hash this would on average take 2^255 tries to crack it. So it would technically take so long that worrying about it gets rendered useless
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