Reading assignment: Hashing

Blockchain and Bitcoin 101
#383
  1. What is the hashing algorithm called used in Bitcoin?
    SHA 256 its a string of 256 code that is solve by a mathematical function to find the value.
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    Brute force is pretty much just guessing and it would take multiple generations and pure luck to solve the hash.
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#384

  1. SHA-256

  2. Hash functions are one-way functions, so it’s very easy to compute them and generate an output, but the reverse is infeasible, given the output to find the original input. In Bitcoin case, SHA 256 has 2^256 different possibilities, so it’s very hard to brute force due to the enormous numbers of possible combinations.

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#385

1- SHA256
2- Because the only way of getting the inputs by just knowing the outputs is through brute force, and it is infeasible to do, it would take many lifetimes.

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#386

  1. SHA256

  2. To brute-force your way through the hashing algorithm would require you to continually guess the hash rate which is just an impossibly huge number it would be unrealistic to attempt

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#387
  1. SHA256
  2. Look at it that way and let’s take a look at a recent block that was mined, for example, block 388368. Looking at this block on blockchain.info, you can see that the hash for this block is:
0000000000000000021ff110a589e44f56979254a204557311204f803910fdfa

It took roughly 10 minutes for all of the miners (doing a combined 700,000,000 giga-hashes per second) to find the above hash which has enough leading zeroes (17) to meet the difficulty requirement of the network at that time. Since the remaining digits after the first 17 leading zeroes could have been anything, there are 16^47 (i.e.16^(64-17)) possible hashes that could have been found which would have satisfied the difficulty requirement (which is 3.92 * 10^56), yet it took all of the mining power of the entire bitcoin network ~10 minutes to find just one hash that met the requirement.

To crack a hash, you need not just the first 17 digits to match the given hash, but all 64 of the digits to match. So, extrapolating from the above, it would take 10 * 3.92 * 10^56 minutes to crack a SHA256 hash using all of the mining power of the entire bitcoin network. That’s a long time.

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#388

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

2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
To crack a SHA-256 algorithm, around 2^256 operations would be needed. Such a huge amount of possible answers would take so much time with the current technology. That’s why it is almost impossible to brute-force a hash.

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#389

1] SHA 256
2] As SHA 256 has a Puzzle Friendly property making it infeasable to computate the input from the output

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#390
  1. Bitcoin uses SHA256
  2. Brute forcing is improbable due to SHA256 making it infeasible to calculate an input from an output. So much computational power required to have half a chance would be infeasible to achieve.
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#391

The Algorithm for hashing in BTC is SHA256

It is unfeasible because the number of possibilities in which a miner or a pool of miners may find the solution is basically huge and time consuming.

#392

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

    SHA- 256
    Secure Hash Algorithm- 256 bit

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

It would take an emense amount of time to match the input and the output hash. The 256 bit input would have to go through the hash algorithm possibly 256 times to find the matching input and hash output.

#393
  1. The hashing algorithm in Bitcoin is called SHA-256
  2. SHA-256 is a 256 bits length digit number, and even the smallest change in the input changes the Hash output drastically. Making it really hard, long or even impossible to have a block collision.
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#394
  1. The hashing aligorithm bitcoin uses is called SHA 256
  2. This hashing algorithm is really hard (almost impossible) to brute-force because it uses so many variables that the amount of time it would take to be successful would take many lifetimes to complete typically. Therefore it is not worth the effort.
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#395

Answers

  1. SHA-256 (Secure Hashing Algorithm 256)

  2. It’s “infeasible” to determinate the original input from the hash value. The only way to find an input from an output is to pick up a random input, hash it and compare the output with the target hash and repeat until you find a match. In SHA-256 the average odds to do this is 2^128/2 = 2^127 = 1,7 * 10^38, a very huge number!!

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#396

Yes, eventually it could be possible, but we probably reach consensus to change the encryption to something more secure by this time.
Sha256 is probably very safe for a very long time, but eleptic curve cryptography is much more vulnerable to this threat.

Watch Andreas talking about this topic:
https://youtu.be/wlzJyp3Qm7s

#397

The input can have any size, the output (Hash) is 256 bit. So you need to randomly hash data until you find the original input of that certain hash. So the input can have much more characters or numbers to guess.

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#398
  1. Sha-256
  2. The computation involved to do it will take couple of lifetimes.
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#399
  1. BTC hashing algorithm is SHA256
  2. It’s really hard to brute force it because of the computing power needed. From what I know a quantum computer would be necessary.
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#400
  1. SHA-256
  2. Because there are to many option to try. in order to be able to get the hash function you have to give the right imput, because the imput can verify so much it is almost impossible to re-create that imput.
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#401

1.SHA-256
2. There is just way too many possible outcomes to simply brute-force since the input can be any size.

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#402
  1. sha-256
  2. chances are so little to succed it is almost impossible
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