Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#4861

Homework on Hash Functions - Questions

    1. Hash function is the result of the sha256 one way incryption.
    1. as verifications for transaction and mining
    1. Collision resistant hash function is when it is almost impossible to find 2 or more indputs that result in the same output.
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#4862

  1. Describe hash functions with your own words
    -A hash function is a function which each unique input has a unique output and is unidirectional, in which it cannot be reversed from output to input.

  2. How are hash functions used in cryptocurrencies like bitcoin? (Try to research this on your own, we will cover this later in the course but challenge yourself and see if you can find information on this already now).
    -Used to write new transactions in the blockchain through the mining process. Finding the nonce requires generating a specific hash with data unique to the block.
    -Miners

  3. What does it mean when we say that hash functions need to be collision resistant? (We didn’t use the term “collision resistant” in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, that’s how you learn best).
    -Low probability that two inputs will generate the same output hash.

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#4863

Q,1.Describe hash functions with your own words
A.1.For any given input(s). a output(s) resultant is calculated

Q.2.How are hash functions used in cryptocurrencies like bitcoin? (Try to research this on your own, we will cover this later in the course but challenge yourself and see if you can find information on this already now).
A.2.Used to create blocks, which are then added to historical blockchain to have immutable properties

Q.3.What does it mean when we say that hash functions need to be collision resistant? (We didn’t use the term “collision resistant” in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, that’s how you learn best).
A.3.The hash function does not give same output(resultant) with different inputs

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#4864
  1. Hash functions are (1-way) algorithms that are used to write Tx on a blockchain (via computations). Particular input always gives (identical) unique output. All outputs have the same fixed length.
  2. They are used to write transactions on the blockchain. Transactions are the input for the hashing algorithm which gives the (encrypted) output.
  3. Collision resistance relates to how cryptographically secure a hash functions is. If a hash function is collision resistant it means that it is (almost) impossible to find an identical output for different inputs.
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#4865

1.Hash Function is the process of having an input item of whatever length reflecting an output item of a fixed length.

2.In simple terms, hashing means taking input of any length and giving out an output of a fixed length. In the context of bitcoin, the transactions are taken as input and run through a hashing algorithm ( Bitcoin uses SHA-256) which gives an output of a fixed length.

3.A hash function H is collision-resistant, if it is hard to find two inputs that hash to the same output.

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#4866
  1. Hash functions are functions that produce a unique output for each unique input, creating unique fingerprints for data.
  2. Hash functions are used in bitcoin mining as they code new transactions onto the blockchain. This is an essential to Bitcoin as it works as a proof of work system, that encourages miners to code the transactions, and in return earn bitcoin.
  3. Collision resistance means that two different inputs will not result in the same output.
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#4867

1.- A Hash function is a mathematical process in which we input something, it is operated, and it returns a fixed length of information.

2.- In BTC, a hash function works the following. We want to send some BTC to a friend, so we input the amount we´ll send, then we see how much it´s going to cost us sending that money, after that we authorize the transaction. That transaction later will be sent to the mining rig will be mined and just until then it will be added to the block. In BTC we have to keys, the public and private key. Both are necessary for the hash function. When a miner picks up the transaction from the Mining Rig, it´s the digest from the your private key and the message, so he will have to run the algorithm to figure out the Public key of the Wallet that sent the transaction. That´s what I have understood about the hash Function. If I´m wrong, can you be so kind to redirect me to the right path. Thanks

3.- By collision resistance we refer to the augmentation in the complexity to reduce the possibility of finding two different hash inputs which have the same hash output.

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#4868

  1. A Hash Function is a “One Way” input computation / function that can not be reversed ; decoded that renders a unique encrypted alphanumeric output.

  2. Hash Functions are used in cryptocurrencies like Bitcoin for the purpose of being the backbone of Security to the Decentralized network, and the mining ; creation of new blocks making them easily identified on the Blockchain.

  3. A hash functions need to be collision resistant so that 2 of the same inputs do not produce ; compute the same output.

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#4869
  1. The Hash function is to apply any kind of input information and receive an output of a fixed length.
  2. One of the main functions of Hash functions is that a small change in input will produce a different output, this is applied in Bitcoin blockchain network to ensure immmutability, as we will be able to verify immediately when the information is modified.
  3. Collision resistance, that it is impossible to get the same Hash data from two different outputs.
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#4870
  1. Functions which input data is impossible to guess from the output data (hashed data).
  2. Hash functions are used to reward miners through the Proof of Work function. If a successful verification occurs new blocks are produced and therefore the miner is rewarded with new bitcoin.
  3. Collision resistant means that two inputs hardly ever hash to the same output.
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#4871
  1. Hash functions is an input of numbers or letter then you put in in Sha 256 and get a unique set of numbers that cant be reversed.
  2. Hash function keep the blockchain that bitcoin is on secure. If somebody was able to to reverse the output to the input bitcoin would cease to exist because it no longer secure.
  3. I think it means you cant find two different inputs and get the same output.
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#4872

good explantions my guy. very helpful

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#4873
  1. A hash function turns a string of data into 256 bits providing a unique digital fingerprint.
  2. Hash functions are used in cryptocurrencies by encrypting data and preventing new coins to be minted.
  3. When talking about collision resistant wo different inputs should not have equal hash outputs.
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#4874
  1. Hash functions are one-way functions that hash any given information. if the information is the same it would produce the same hash, however if you change something the result will be very different.
  2. Hash functions are used to make transactions in a blockchain possible by producing a hash digest and confirming the transaction, also confirming the balance etc.
  3. Hash functions need to be collision resistant in order to make it almost impossible to have same functions for different inputs
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#4875

  1. Describe hash functions with your own words
    Hash functions are algorithms that take an input and yield an output such that the output is irreversible.

  2. How are hash functions used in cryptocurrencies like bitcoin?
    Hash functions are used in mining, where the block header is rehashed with an additional constant (nonce) to find the hash that starts with a set of superseding zeros. They are also used for “digital signatures”, which are digests that can act as your private key’s thumbprint to prove that your private key was responsible and condones a transaction.

  3. What does it mean when we say that hash functions need to be collision resistant?
    It would be detrimental to the cryptocurrency. No two inputs should output the same cryptographic digest. Otherwise, malicious users can mimic data.

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#4876
  1. Hashfunctions are one-way functions with repeatable given identical inputs with fixed-length-output, bitwise sensitive to inputs and cannot recover input from output.
  2. Hashfunctions are blocks which contain hashes of previous blocks in the chain. Miners adjust signature data until hash produces n-zeros. It also requires a lot of randomization.
    3.Collision resistant is having a very low probability of two inputs generating the same output hash. Not impossible but statistically insignificant.
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#4877
  1. Hash functions only go one way/are unidirectional, in that each unique input can only produce on unique output, a type of digital fingerprint.
  2. Hash functions are used to write new transactions into the blockchain.
  3. Collsion Resistant: the high unlikelihood (virtual impossibility) that two miners arrive at the same hash.
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#4878

1. Describe hash functions with your own words
Hash functions are functions that take a piece of binary data (representing a string, image file, etc. etc.) and generate a hexadecimal number as output referred to as a hash.

  1. **How are hash functions used in cryptocurrencies like bitcoin? **
    Transactions on the btc network are grouped into blocks and sent to miners to be verified. What miners do is to guess a number called a nonce so that when this number is taken together with their block of transaction data and the previous blocks hash the computed hash for their block is less than or equal to a target set by the network. Once this number is guessed that results in a hash being produced less than or equal to the target value the block is added to the blockchain and the blocks hash becomes used in mining the next block.

3. What does it mean when we say that hash functions need to be collision resistant?
When hash functions are collision resistant it means that it is very very difficult to find two inputs to the hash function that generate or hash to the same hex output.

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#4879

  1. Hash functions have a unique digital fingerprint. You can
    only go from input to output. And when using SHA-256 the
    reverse is impossible.

  2. Hash functions in bitcoin are used in the mining process.
    The inputs are all recent, not-yet-confirmed, transactions. There
    are other inputs relating to timestamp and reference to previous blocks.
    Miners input into the block hashing algorithm to solve the hash for
    bitcoin blocks. The combined power of all the computers in the network
    takes approximately 10 minutes to solve a block.

3.It should be hard to find any two inputs that hash to the same output.
If this occurs security is compromised.

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#4880

1. Describe hash functions with your own words
It’s an algorithm that takes any form of data at any size and translates it to a unique alphanumeric code that cannot be translated back to it’s previous data form.

2. How are hash functions used in cryptocurrencies like bitcoin? (Try to research this on your own, we will cover this later in the course but challenge yourself and see if you can find information on this already now).
They are used to record new transactions to the bitcoin blockchain.

3. What does it mean when we say that hash functions need to be collision resistant? (We didn’t use the term “collision resistant” in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, that’s how you learn best).
It means that two different inputs should not produce the same output.

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