Reading assignment: Hashing

Blockchain and Bitcoin 101
#322

  1. What is the hashing algorithm called used in Bitcoin?
    Bitcoin uses a SHA-256 Algorithm

  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    Because of the SHA-256 Algorithm, It would take way way too long to bruit force it.

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#323
  1. SHA-256
  2. Because we donā€™t have that much computer power in one moment. It would take very long time to brute force this.
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#324
  1. SHA-256 is the hashing algorithm used in Bitcoin
  2. The hashing algorithm is almost impossible to brute-force because the there is an extremely high number of possibilities. It would take a lifetime (or more) to crack.
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#325
  1. SHA-256
  2. Because the possibility to do that is very little. Something like 2^127 = 1.7 X 10^38
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#326
  1. SHA-256
  2. The total number of possibilities is so large that it is unlikely two people get the same result in their life time.
#327
  1. SHA-256
  2. It is infeasible to brute-force the algorithm because exponentially high number of randomly creating hashes and then comparing them with the hash of the concatenated nonce and contents of the new block. On an average it will take 2^127 attempts before a matching hash can be found which makes in infeasible to do.
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#328
  1. Sha-256
  2. Because it would take a life time to find two inputs to produce the same output in a hash function
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#329
  1. SHA 256 ( Secure Hashing Algorithm 256)

2.Using brute-force means to hash any random number as input and compare it with the output until it matches.
But that would take so much timeā€¦almost infinitely much time compared to a human life.

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#330

  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 already a small change in the input will generate a different output. That would be recognised as a sign to alter the blockchain. The computation to find the same output twice would be extremely long.

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#331

  1. SHA256 (Secure Hashing Algorithm 256 )

  2. To find an input to a specific output by brute force statistically it takes 2^128 tries (2^256 possibilities) and is therefore unfeasible.

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#333

1- SHA-256 is the hashing algorithm used in bitcoin
2- BRUTE FORCE is the only way to find out the input from the output hashā€¦ as pure random guesses would take lifetimes to guess

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#334

  1. The hashing algorithm for bitcoin is called SHA-256

  2. The hashing algorithm is really hard to brute force backwards because by ā€œguessingā€ the input given the output it would take an astronomical amount of guesses to determine the correct input. Even an average amount of guesses would be impractical.

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#335

  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?
    Given the pre image resistance, brute force hacking, though not impossible, is unlikely in a lifetime.

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#336

  1. SHA-256

  2. The amount of possible combinations of hashing the block, concatenate it with the nonce and hash it again to see if it is below the difficulty level are endless.

#337

Answer the questions below.

  1. What is the hashing algorithm called used in Bitcoin?
    SHA256, which means Secure Hash Algorithm with an output lenght of 256 bits, i.e. 64 bytes.

  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    Because the number of tries in an average scenario using a brute-force attack lies between 2^255 and 2^256, which are huge numbers!

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#338
  1. SHA256
  2. Because of pre image resistance. Also, in scenarios where you are just brute force guessing, you are more likely to hit a collision than to get the actual starting parameters.
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#339

  1. SHA-256

  2. It is extremely difficult to determine the input value from the output value (pre-image resistance). Changing the input by a small amount produces an output that is completely different. There is a minute chance that two different input values result in the same output value (collision resistant). For every output Y, given string k is chosen from a high min-entropy, it is improbable to find a value of x such that H(k|x)=Y (puzzle friendly). The output is always 256 bits long. These factors combined make it so computationally intensive to randomly find a solution that SHA-256 is almost impossible to brute-force.

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#340

  1. SHA-256

  2. Because the algorithm includes too many possibilities for anyone to guess in a short time.

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#341

  1. What is the hashing algorithm called used in Bitcoin?
    SHA256 - Secure Hashing Algorithm ( 256 bits )

  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    Since there are 256 bits in the string with a possible 0 or 1 in each position, there are 2^256 possible combinations. At the current bitcoin hash rate it would take longer to crack SHA256 than for the sun to die. Although possibly faster with future advances in computing, this is obviously a sufficiently hard task.

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#342

  1. Bitcoin uses the SHA-256 (secure hashing algorithm 256-bit) hashing algorithm

  2. Hard to mine (find hashes that satisfy criteria for next block) because the hash rate is very high and hence difficulty is high, meaning lots of leading zeros in target and hence small set of acceptable hashes. The attributes deterministic, pre-image restistance, puzzle difficulty.
    Hard to brute force someone elseā€™s hash (collision) due to the enormous number of hashes (2^256=1.16*10^77), like wining the Power-ball lottery (1/292 million odds) nine times in a row.

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