Reading assignment: Hashing

[Farid]

Thank you Mauro! I love the academy man, learning so much!

[ArielVB]

1.- SHA256

2.- Because in order to brute-force it you need an astronomical amount of computational power ( hashing power, which means the research of that data string that was introduced to find the output to integrate one single block in the chain. )

[Mauro]

@Rasselas_Wildcat

It could take multiple lifetimes to get to the answer.

@devalmar

2. hy is this hashing algorithm really hard (almost impossible) to BRUTE-FORCE?
   Because the possibility to match the two inputs is really hard and it will take a really long, long, long… Lifetime

We are talking about millions of years actually.

[Mauro]

@Rob

there are an extremely long number of events one would have to compute to get to the right answer.

@kidsmoney

really big number to guess

Its not that the number is long in itself, but the amount of combinations it would take is astronomically big.

[Mauro]

@jelucamur

2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
   The use of a Nonce value as part of the hash key ensures that the solution is truly random and would require significant computing power to try and break

@Emmett

2.It has to constitute proof of work, in order to be rewarded with BTC

The question was more focused towards the hash function in general. I will rephrase the question. Why is it really hard to guess the input of a given hash?

[Mauro]

I am glad to hear you are learning a lot. I love the academy as well.

[Mauro]

@AdamSo02

2. The difficulty of finding the output is extremely high.

Do you know why?

[Mauro]

@ImmI

2. because it is like football there can be a foot without ball but only both things together is football. To brute-force this, someone would have to try out everything connected with foot.

An interesting way to answer the question. I like it.

[Mauro]

@BryanSC

For SHA-256, you would need to guess 256^2 inputs in order to find the output, which would take an infeasible amount of time.

Uh oh. 256^2 is only 65536. This would have been broken in seconds. You switched the numbers, probably by accident. The number of guesses would be 2^256.

[Mauro]

@HoS

2. The SHA algorithm hash has 64 characters both input and output.

The input is not limited in size. It can be as low as 1 character or as large as you wish. However the output will always be 256 bit long, or 64 digits in the hexadecimal format.

[Mauro]

@cryptoJD

This is very expensive using current computing technologies due to the number of possible permutations.

I would argue that it is impossible rather than expensive.The computers we currently have are no way near efficient to crack it. Because our computers are so inefficient they would need an extremely large amount of energy, which we cannot capture in any way.

[Mauro]

@Cobrati21

• Why is this hashing algorithm really hard (almost impossible) to brute-force?
  With a 256 bit algorithm, it is less likely to be successful in getting your answer utilizing the Brute Force Method.

Why would it be difficult?

[Mauro]

@Euphorical

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

• Because using random inputs in SHA-256 increases the amount of time to brute-force that it is almost impossible.

Using random inputs does not make the brute force impossible. What makes it impossible is the amount of possible combinations that you would have to go through in order to brute force it.

[Mauro]

@CryptoPadawani

I think I got these answers right, other than that my brain is exploding from confusion haha
Guess I need a break, tomorrow a new day!

Looks good to me.

[Mauro]

@CryptoDenise

This hashing algorithm is really hard to brute force because it is a string of text generated by a formula using a mathematical function, which would require a large amount of computation to produce an output. The only way to solve this puzzle is through brute-force, basically guessing. A random input is picked up, hashed and repeated until a match is found. Over time, the length of the text increases as zeros are placed at the beginning. This increases the difficulty.

The question was regarding the hash function in general. Finding an input based on the output (brute forcing) is not possible due to the amount of the combination we would have to go through. In bitcoin, hashing is used to secure the blocks. A miner needs to create a hash that will be lower than the current difficulty target, otherwise it will not be a valid block. Your answer mixed both of these things, which made me confused a bit. Hopefully this will clear everything.

EDIT: I see your other reply.

@CryptoDenise

Change my answer. Because of pre Image resistance, using brute force is nearly impossible.
So here’s the change:
This hashing algorithm is really hard to brute force because of the number of possibilities that are available to solve the puzzle.

This is the correct answer.

[Mauro]

@qwiqfire

2. The hash generated is so large, the algorithm to determine the hash would take to long to figure it out.

The hash that is generated is not large in size. In fact its only around 32bytes. What makes brute forcing impossible is the large amount of combination we would have to try. This would be a hard computational task.

[Mauro]

@Mina_Bebawy

Because it is almost a one way function.
It is so easy to convert data into a hash

Hash functions need to be one way functions. Exactly, its easy to convert data into hash but not hash into data. This is due to the large amount of combinations we would have to try in order to get the original input.

[Mauro]

@jwhite

2. The randomly selected nonce is from a distribution that is so huge, that the probability of choosing the input based on the output is nearly impossible.

Quite an interesting way to answer this question, in fact, you implemented it very well in bitcoin. It is indeed impossible for a miner to put the required hash and then reverse the function to find the nonce. A great example why miners must spend all that electricity to find the correct hash.

I tweeted you reply: https://twitter.com/Mauro4897/status/1276277797166690304

[Mauro]

@Mick

Brute forcing would require one to compare two hashes that match together.

Brute forcing a hash means you are willing to try every possible input combination until you get that desired hash.

[Mauro]

@Petr_Hajdusek

1. What is the hashing algorithm called used in Bitcoin?
   Hashing is generating a value or values from a string of text using a mathematical function.

Correct. But the question is asking us what is the name of the hash algorithm used in bitcoin?