Reading assignment: Hashing

Blockchain and Bitcoin 101
#363
  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 properties that better explain this are:
  • PRE-IMAGE RESISTANCE - infesable there is a very low probability of determine the input which generated di otuput. It is nearly impossible to guess the inputs.
  • PUZZLE-FRIENDLY if the SALT is casual (=random string that we add before the message) it is rather impossible to track the input unless you try all the different keys.
    So, given a causal salt and a fixed number of solutions Y, we have to find a message where the key , concatenated to the message, belongs to the set of solution Y.
  • The SHA-256 has not shown collision for now, which means also that the chance to find a collision (=casual match) is so low that it will requires milions of year.
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#364

1 [SHA-256]
2 because you will need lots of time to randomly pick up a random input, hash it and then compare the output with the target hash and repeat until you find a match.

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#365

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

  2. This hashing algorithm is almost impossible to brute-force because the possibility to find the input from the output would take more than a lifetime to be found by this method, you would need to do 2^128 computations to find it.

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#366

  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) Due to the math and protocol of the hash function, it’ll take you a life time to try and work it out.

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#367

Sha - 256

Because (almost) every possible input creates a unique hash with 256bits.
As the hash of two almost identical inputs are drastically different and not correlated it is extremely difficult and almost impossible to find the same hash again as it would take way too much time, brute forcing the input of a hash.

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#368

Another piece of content to understand hashing :slight_smile: https://www.youtube.com/watch?v=2BldESGZKB8

#369
  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’s to systematically check all possible keys until you find the right one. But there are too many possibilities and the keys can have different lengths, use numbers and lettres (with capital lettre or without).

You probably have more chance to win the lottery.

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#370
  1. The hashing algorithm used in Bitcoin is called SHA-256.
  2. The SHA-256 has certain properties that enables Bitcoin’s system stay secure such as quick computation and completely different hash values (output) after small changes in the input. It is unfeasible to find one’s private key adress because of these properties.
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#371

  1. SHA-256

  2. The difficultiy of brute-forceing a hash increases exponentially with the length of the hash-function.

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#372
  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?

It’s nearly impossible to brute-force SHA-256 because it produces a unique signature that would be nearly impossible to match since each input creates its own unique hash, that it would take too much time to brute-force it.

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#373
  1. SHA 256
  2. The probability of finding two inputs to produce the same output is infeasible.
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#374

  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?
    Multiple hashings with 2^256 possible ‘keys’ makes the Forging Probability of the input… very very difficult and costly.

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#375
  1. SHA 256
  2. It is almost impossible to find the input based on the output.
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#376

1 - SHA-256
2 - Because with the brute-force method a random input is picked and compared to the hash. In an average scenario brute-force would have to do 2^255 operations to find the input of each hash. This may become a problem though in the future with the development of nano-computers.

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#377

Answers:

  1. SHA-256
  2. It could happen but the possibility of it happening in our life or other life times is impossible.I do not understand why after reading what you suggested.
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#378

  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?

Secure Hashing Algorithm 256 is extremely hard to brute force attack because the number of bits it brings to it’s pre-image resistance. On average it would take 2^127 hash comparisons to hit upon the correct input. This is because it produces a 128 bit hash. I’m assuming that it’s called SHA 256 because it produces a 128 bit hash. Since it’s using the binary system 128 x 2 = 256.

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#379
  1. SHA-256
  2. Because of the long time that are needed to guess the huge possibilities (up to 2^256 – 1 times).
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#380
  1. SHA-256 is the hashing algorithm for Bitcoin.
  2. The amount of data 256 character needs a very long time to brute-force.
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#381
  1. SHA -256
  2. The number of possibilities under the hash is sooo huge that it is worse than finding a needle in a bale of hay.
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#382
  1. SHA-256
  2. Because hashes are too long to be bruteforced