Reading assignment: Hashing

Blockchain and Bitcoin 101
#102

Hashing

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

  • Secure Hashing Algorithm 256 (SHA256)

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

SHA256 Possibile Hashes [P]:. 2^256 = 1.16*10^77 H
Bitcoins Hashrate [R]:. 100,000,000 TH/s = 1*10^20 H/s
P/R = 1.16*10^77 H / 1*10^20 H/s = 1.16*10^57 s

1.16*10^57/60sec/60min/24h/356d = 3.77*10^49 years
3.77*10^49 / 13.7*10^9 (Age of the Universe) = 2.75 *10^39 Times the age of the Universe

Even with the entire Bitcoin Network it can take up to 3.77 * 10^49 years to find the right Hash. In Average it would take 3.77 * 10^48 years. The number might be much higher when the guessing is random. Than it could be possible to guess a hash multiple times which is not considered in this estimation.

Please let me know if there is a mistake in my way of thinking. :slight_smile:

3 Likes
#103

1 Hashing algorithm for Bitcoin is SHA-256 (Secure Hashing Algorithm 256).
2 SHA-256 hash algorithm produces a 256- bit hash. With the “brute-force method”
you need to try on average 2^(256-1) possibilities in H(A) to match your A in (H(A)=A) , almost impossible, to much time consuming.

#104

1- SHA 256
2- Because every input has a unique hash and when lots of data is being handled the possibilities of finding a match is infeasible.

#105
  1. SHA 256. 2. The number of possibilities make it infeasible to brute force guess.
#106
  1. SHA - 256 (Secure Hashing Algorithm 256)
  2. Because of pre-image resistance which state that given H(A) it is feasible to determine A, where A is the output and H(A) is the output hash.
#107
  1. What is the hashing algorithm called used in Bitcoin? SHA-256
  2. Because we don’t have the computational power to test all the possibilities in a life time 2^256 is a huge number, better to use this power to mine bitcoin :wink:
#108
  1. SHA-256
  2. Because if there is even a small difference in the input the output is different. Therefore it is very hard to “guess” the input from the hash.
#109

  1. SHA-256

  2. The hashing algorithm is almost impossible to brute force because it would take a massive amount of computing power.

#110

SHA 256

The total number of possibilities is so large that the odds are nearly impossible.

#111

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

  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    High Min-Entropy makes hashing algorithm almost impossible to brute force, it takes so long it doesn’t even matter.

#112

  1. SHA-256

  2. the hash algorithm contains the data from previous blocks, so any changes to the block will change the hash of all the previous block. making it almost impossible to brute-FORCE.

1 Like
#113

  1. The hashing algorithm used by Bitcoin is SHA-256.

  2. The hashing algorithm is almost impossible to brute-force because there are 2^128 possibilities, a small change to the input completely changes the output, and it is pre-image resistant.

#114
  1. SHA-256
  2. The odds against working on the first try or couple of tries are astronomical, and it will take so long to figure it out that is simply does not matter.
#115

  1. SHA-256

  2. Its almost mathematically impossible to get the same out come in our life time.

#116
  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? You will need to guess about 5.78x10^76 times to guess the input from the output hash. Having to guess this many times at random makes it almost impossible to guess the right input.
#117

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?
Any little change to the input will create a completely different output, so there are thousands of possibilities for the input. This will take lots of time to solve.

#118

Hello,

  1. Bitcoin uses the SHA-256 algorithm. (SecureHashingAlgorithm).

  2. sha 256 is pre-image resistant, making the input of the hash not recoverable from the output. any small change in the input determines a completely different output. It can be brute forced, but it would take extraordinary computational power and the results would arrive years later. In the meantime, the blockchain would have progressed, and modifying that block would cause problems with both the preceding and following blocks.

#119

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 hash may be found after 2^255 attempts

#120
  • What is the hashing algorithm called used in Bitcoin?
    • SHA-256, where SHA means Secure Hashing Algorithm.
    • The algorithm always outputs a 256 bit result.
  • Why is this hashing algorithm really hard (almost impossible) to brute-force?
    • The average number of guesses to produce the same hash result is 1.7X10^38. This number of guesses is so large that it takes an extremely long time to solve. Depending upon the speed of the computation, it could take decades!
#121

1- SHA-256.

2- Because it like a 2 pieces puzzle, where 1 random string (K) and the other (x) is by from two encryted or hashed adresses. Only when one is able to decrypt (x) is able to decrypt K.

Is not right at all, right?