Reading assignment: Hashing

Blockchain and Bitcoin 101
#1870
  1. The hashing algoryhtm used in Bitcoin is called SHA-256
  2. The algorythn is based on the puzzle friendly property:
    For every output Y, if a nonce k is chosen for a distribution with very high minentropy, it is almost impossible to find x such that H(k|x)=Y
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#1871

  1. SHA-256

  2. Due to the fact that all transactions are linked to previous transactions you would have to brute force a ridiculous amount of inputs just to get required hash outputs for each block on the main chain, this would take so long the risk of being hacked is negligible.

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#1872

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?
Using SHA-256 hash there’s 2^256 possibilities making it infeasible to try each one.

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#1873

  1. It called Secure Hashing Algorithm (SHA-256)

  2. As it uses an encryption algorithm it will take much time to decipher the encryption.

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#1874
  1. SHA-256
    2.You have to pick a random input, hash it and then compare the output with the target hash and repeat until you find a match in other words it will take a very long time
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#1875

  1. sha-256 is the hashing algorithm used in bitcoin.

  2. The hashing algorithm is really hard to brute-force because it takes so long that it is not worth it. It would take more than a couple of generations of lifetimes to even get close.

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#1876

Answer the questions below.

  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? SHA-256 has a 256-bit hash, so on average it would take 2^256/2 = 2^128 = 3.4 X 10^38 guesses. If a supercomputer could perform the check on a peta-cycle basis (10^15 checks per second), it would still require (on average) 3.5 X 10^23 seconds or approximately 11,000,000,000,000,000 years!
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#1877
  1. What is the hashing algorithm called used in Bitcoin?
    A. SHA-256
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    A.It is near enough impossible to reconstruct the initial data from the hash value. This would make Brute Force almost impossible, and also less chance of a collision by two messages sharing the same hash
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#1878
  1. SHA256
  2. Hasing function is a one way algorithm, meaning you can not deduce what the input string is based on a known output string. So to find out what the input string is, you potentially need to try 2^128 -1, which is an astronomical number.
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#1879
  1. What is the hashing algorithm called used in Bitcoin?

Bitcoin uses the sha-265 hashing algorithm, which produces cryptic elements of a fixed length of 256-bit

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

Because of the iteration time to decipher an input from the hash output. It is astronomically large e.g. for a 256-bit it would take in the average case scenario (2^256/2) iterations.

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#1880

  1. Bitcoin uses SHA-256.

  2. it will takes a very long timetll it become irrelevant.

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#1881
  1. SHA-256
  2. It is not impossible (rather infeasible) because by 256-bit hash it is very difficult and time-consuming to be successful. To find (randomly) the correct input it would take you a really long time, so it doesn’t matter anyway
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#1882

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?

This is because you only have the input to hash and to compare it against the output. Once the input is changed slightly i.e. Changing the case of a letter in a phrase/sentence the hash input changes a lot. This means you would have to hash a lot of times to match the input, this will take too much time and makes it the process pointless from a speed and efficiency aspect.

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#1883
  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?
    a) It will take longer than the existence of the universe to try and solve the hashing algorithm for bitcoin, it undergoes more than 2 times hashing a chain of 26-35 numbers and letters.
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#1884

What is the hashing algorithm called used in Bitcoin?

SHA-256

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

Preimage Resistance - It is virtually impossible to find any input that hashes to a specific output. (Given H(A), it is infeasible to determine A.)
Collision Resistance - It is infeasible to find two inputs that hash to the same output. Even with the birthday paradox, the possibilities of the time and computational power needed to try and brute-force SHA-256 is highly improbable.
Puzzle Friendly: “For every output, “Y”, if k is chosen from a distribution with high min-entropy, it is infeasible to find an input “x” such that H (k|x)=Y.” The distribution from which the value is chosen is so enormous that choosing a random matching value is highly unlikely. And in addition to the computation of the hash, a nonce is also added, making brute-force even more improbable.

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#1885

  1. Bitcoin uses a hashing function called SHA 256

  2. SHA 256 is really hard to brute-force because with the limitations of current cpu technology, it would take to much time, there are to many possibilities to make it feasible.

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#1886

  1. SHA-256

  2. The number of hashes is so big that it will take a very very long time.

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#1887

  1. The hashing algorithm for Bitcoin is SHA-256 or Secure Hashing Algorithm 256.

  2. A hashing algorithm is difficult to brute-force because you would have to randomly guess the correct input to the hash; a hash of 256 has 2^256 possibilities for inputs.

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#1888
  1. What is the hashing algorithm called used in Bitcoin?
    SHA-256 security hash algo - 256
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    Basically, this means that you have to pick up a random input, hash it and then compare the output w/ the target hash, and repeat until you find match. Best case, you’re luckier than a dude getting struck by lightning. Worst case, you get you answers after 2^128-1 times. Average scenario, you will find your answer “somewhere in the middle” (2^127 = 1.7 x 10^38 = huge f**king number.
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#1889
  1. Bitcoin uses algorithm SHA-256 (Secure Hashing Algorithm 256).
  2. In the used SHA-256 algorithm number of variations is so big, that taking a random input, hashing it, and comparing it to a target hash, would simply take too long. But in theory it is possible.
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