Reading assignment: Hashing

Blockchain and Bitcoin 101
#2110

1.SHA-256
2.it takes so long to do it becomes unlikely

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#2111
  1. SHA-256
  2. It will take too long (like really really long)
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#2112

  1. The hashing algorithm called used in Bitcoin is called ā€œSecure Hashing Algorithm 256ā€ (SHA-256).

  2. This hashing algorithm is really hard (almost impossible) to brute-force because it is infeasible to find an input x such that H(k|x) = Y. You literally would have to try all of the outputs to find the input which is 2^256 different possibilities.

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#2113
  1. SHA-256:
  2. It would take to much time to find an input that determines the outcome we are looking for.
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#2114
  1. What is the hashing algorithm called used in Bitcoin? Bitcoin uses SHA-256.
  2. Why is this hashing algorithm really hard (almost impossible) to brute-force? To calculate the input from the hash by using the brute force method is next to impossible due to the number of possibilities for the input to get the exact same hash would take to long, maybe a life time.
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#2115

  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 takes so long to breach that is not feasible to even try to accomplish.

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#2116

  1. sha 256

  2. it is so hard to brute force because you have to geuss all 256 bits to get the answer. you have to try 2^128/2 = 2^127 times to geuss the answer.

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#2117

  1. SHA 256

  2. The above formula generates the hash, which helps to protect the security of the transmission against tampering. It will take a long time to crack SHA 256 crytographic hash function using all the mining power of the entire biotcoin network. Each input of a hash is unique, collision resistant and follows the birthday paradox.

#2118

  1. SHA 256

  2. SHA 256 one of the most secure hashing functions. It is impossible to brute force it because it is collision resistant and follows the birthday paradox

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#2119

1- The Hash Algorithm used in Bitcoin is SHA 256 which provides, no matter the size of the input, a result of 256k
2 - This is due to the pre image resistance property where it is practically impossible to know the input using only the Hash. It is possible to do it but it would take so long that it doesnā€™t matter.

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#2120

  1. Hashing algorithm SHA-256

  2. There would be way too many output possibilities and it would take a very long time that it wouldnā€™t even matter.

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#2121

  1. Bitcoin uses the SHA-256 (Secure Hashing Algorithm 256) hashing algorithm

  2. This SHA-256 hashing algorithm is almost impossible to brute force because of the amount of computation possibilities. The amount of computational power and time to brute force is astoundingly large. According to one google search, 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.

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#2123
  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 is infeasible to determine the input data based on the output hash. Brute force breaking takes very long and therefor its possible success is statistically insignificant.
  • On average it would take 2^127 = 1.7 X 10^38 tries, which is a lot.
  • on a side noteā€¦ some day quantum computers might pose a risk as they are multitudes more powerful than current computers. This threat is not limited to cryptos and impacts most encryption schemes that are currently in widespread use.
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#2124
  1. SHA-256
  2. Because any slight changes done to the algorithm will cause a chain reaction to the other algorithms, making it almost impossible to hack.
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#2125

Iā€™m going to answer + ask for clarity

  1. SHA- 256
  2. Due to the fact that the the nonce is comes from a high min entropy distribution and that the input could be any length means that the number of blind guesses required to solve for the input, based on the 256 bit hash comes close to infinity

QUESTION:
Isnā€™t bitcoin mining basically brute force? Is it that though itā€™s almost impossible for a single person/ machine to brute force cryptographic hashes, the sheer number of mining machines attempting to brute force bitcoin hashes around the world, makes it so that itā€™s likely that at least one of these machines will solve the hash within 10 minutes?

If so, how did it work early on, before the hash rate grew?

From my questions, I can see that Iā€™m missing something lol.

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#2126
  1. SHA-256
  2. Because the number of possible options is too high.
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#2127

Mining is not the same as brute force. With brute force miners are trying to find an input that would result in the same output as a target hash, while miners are trying to find a new hash that is below a certain target.

Its all about probability, the target is set up in a way that miners will find a new hash approximately every 10 minutes, its is not exact, they might find it in 2 minutes or 15 minutes. The difficulty adjusts based on the hashrate so the entire network will mine a block approximately every 10 min.

It worked in the same way, the threshold to find the hash was much more simple. :slight_smile:

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#2128

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?
The amount of data is massive: In an average scenario, you need to do approximately 2^256/2 = 2^128 (340 undecillionsā€¦) computations to find the hash. So it is infeasible to find it, and thus to brute-force the system in oneā€™s lifetime.

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#2129
  1. SHA-256
  2. Because it is Pre-Image Resistant. Therefore, you would have to determine the input based on an output that has an extremely low chance of being randomly guessed correctly.
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#2130

Reading assignment: Hashing

SHA-256

You cannot determine the input from the generated hash. The number of possible inputs is so large you could not calculate the hashes of those possible inputs in any personā€™s lifetime. You wouldnā€™t have success comparing the known hash to the generated hashes of your ā€œrandom guessā€ input, making the hashing algorithm ā€œpre-image resistantā€. Some properties of the hashing algorithm prevent cheating the requirement to brute-force, like ā€œcollision resistanceā€ and the fact that small changes in input result in major differences in the output hash.

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