Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#3074

1. Describe hash functions with your own words
Hash functions are one-way unique input(s) that give a unique output(s).

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).
In cryptocurrencies like Bitcoin, hash functions are used to record new transactions into the blockchain through the mining process. Bitcoin hashing uses SHA-256 to convert any input to a 256-bit output.

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).
Hash functions need to be collision resistant to provide security in order to deter attacks against the blockchain. To accomplish collision resistance no two inputs that hash to the same outputs.

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#3075

[quote=“ivan, post:1, topic:8430”]

  • Describe hash functions with your own words
  • 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).
    *1. Describe hash functions with your own words
    Hash functions are used to produce digital unique outputs, they are referred to as a unique digital fingerprint,

  1. 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 by miners to solve equations to produce new BTC.

  2. 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).
    This means that they do not result in the same output. If one character or spacing is adjusted the output must be different than another output.

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#3076

  1. A hash function is a process that transforms any piece of data (input) and converts to a unique fingerprint (output).

  2. Hash functions are used to write new transactions to to the blockchain. This is done through the mining process and requires processing power. This is the reason coins are mined slowly.

  3. Collision resistance means it is highly unlikely (but not impossible) that two inputs can create the same output.

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#3077

Hash function are functions that receive an input of any length and outputs a fixed-length unique number.

They are used in several parts of the Bitcoin protocol, one of the most important is in the proof-of-work consensus process. Bitcoin is in essence, a competition of computers. They try to find the input that generates a specific output of the SHA-256 function, posted by the network. The computer that finds the input wins the incentive (bitcoins), but by finding it, it has proved that a lot of computational power was spent by the whole network, as only by brute-force guessing is how the input was found. The SHA-256 function is irreversible. The network can easily verify that the input is correct and be sure that a lot of computational power was spent so no hacker intervention is feasible.

Means that no two inputs should generate the same output. In practice this is not possible as the output of any hash function is finite. There will be spaces of coincidence where inputs, given that they can have any value and any length, may generate the same output. The less spaces of coincidence a hash function have, the more collision resistant is.

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#3078

  1. A hash function is a very complex mathematical system used on a Blockchain Network on which it is obtained a unique digital result represented by a series of numbers from 0-9 and letters from a-f in lowercase form given a unique value to the variable of the system.
    Hash functions are unidirectionally solved from the value of the variable side to the result side of the system. This can not be reversed.

  2. In the bitcoin protocol, hash functions are part of the block hashing algorithm which is used to write new transcriptions into the blockchain through the mining process.

  3. When hash functions are collision resistant it is hard to find two inputs that hash to the same output; that is, two inputs a and b where a is different from b but H(a) = H(b).
    The harder the inputs are to find, the more cryptographically secure the hash function is.
    Collision resistance is the most important property of a blockchain network when it comes to its safety.

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#3079

  1. Describe hash functions with your own words
    Hash functions takes input data and outputs2 a unique alphanumeric string. The process is not able to be reversed to find the original input.

  2. How are hash functions used in cryptocurrencies like bitcoin?
    They are part of the block hashing algorithm. Blocks are solved by combining previous inputs with their own input data. A change in hash data means a cascading change in the blocks, rendering them invalid.

  3. What does it mean when we say that hash functions need to be collision resistant?
    Collision resistance is the unlikeliness of two different inputs resulting in the same hash output.

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#3080

  1. Mathematical algorithm that maps data of arbitrary size to a one-way bit array of fixed size.

  2. Bitcoin protocol uses hash functions for adding new blocks to the blockchain through the mining process. It takes transactions into fixed irreversible bits using SHA-256 algorithm.

  3. Collision resistant is a property of cartographic hash function if it is hard to find two inputs that hash into the same output.

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#3081

  1. Describe hash functions with your own words

    Hash functions are functions where each unique imput has a unique output. Also, its not possible to
    go 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).

Hash functions are mainly used in cryptocurrency’s for transactions.

  1. 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).

You mean that two diffrent inputs cannot have the same output.

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#3082
  1. At this point I would only be memorizing, from what I understand the “Hash” is the output of the function from the algo after a file or data has been feed into a computer contain the SHA-256 or what ever platform is being used. It’s a unique cripto thing.

2 / 3 I’m working on this.

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#3083
  1. Hash functions are algorithms that give any input a unique output or signature that cannot be exploited or reversed in any way.
  2. In the bitcoin protocol, hash functions are part of the [block hashing algorithm] which is used to write new transactions into the blockchain through the mining process.
  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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#3084

  1. Hash functions are like a finger print. Every unique input leads to a unique output. It is a one way street so you cannot reverse engineer the output to the input.

  2. It is used for mining bitcoin as part of the hashing algorithm. It’s called ‘proof of work’ . A function translates an input to a certain fixed length output.

  3. Collision resistant means it should be impossible for two different inputs to result in the same output.

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#3085

:clock1: :clock4: :clock8: :clock12: :alarm_clock: :stuck_out_tongue:

#3086
  1. Describe hash functions with your own words
    a) Hash functions take data (input) and converts it to a unique code, or digitial signature specific to the input data that was received. The ouput (hash) cannot be translated to understand what the original (input) data was.
  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.) Hash functions are used in bitcoin, by taking an input (requested transaction) and having it confirmed by miners. Once the miners have verified the data, the transaction is added to the ledger being identified by a digitial signature or hash.
  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) Functions need to be collision resistant so two different inputs (requested transactions) wont have the same output (digitial signature, or hash)
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#3087

  1. hash functions are function that are monodirectional cause you can go just from an input to an output. Changing just one variable it will completely gives you a different result

  2. it can be used to protect your privacy, like for example your wallet

  3. that is difficult to find two inputs that gives you the same output

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#3088
  1. Describe hash functions with your own words
    is the process of transforming letters or number in to a long alpharethmetic character called hash
  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).
    every block with information created gets a unique hash number so if anything in the block change then the hash is changing too but every block produced has its own hash and the hash of the previous block created.So if you change anything on any given block the hash numbers will not match so the block wont be accepted
  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).
    When produsing hashes it is possible that 2 different inputs will result in the same hash! that can be used by an attacker in order to cheat the system into introducing a different paper with the same hash! It is important that hash functions should be collision resistant(hard to be discovered by anyone) in order to prevent this type of attacks
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#3089

  1. When an input is given into hash functions it produces a unique digital fingerprint of that input that cannot be reversed.

  2. In cryptocurrencies like Bitcoin hash functions are part of the block hashing algorithm and they are used to write new transaction into the blockchain through mining.

  3. Hash functions need to be collision resistant means that it should be hard to find 2 inputs that produce the same output.

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#3090

[quote=“ivan, post:1, topic:8430, full:true”]
Homework on Hash Functions - Questions

  1. Describe hash functions with your own words

A hash function is a function that uses specific data/information to calculate a unique hash for that set of information. If the slightest change is made within the data the hash will be different and not verifiable.

  1. 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).

Hash functions are used to create a fingerprint for specific data, but in Bitcoin the requirements of that ‘fingerprint’ are what determines how difficult it is to find the correct nonce that results in a new block.
So while it is easy to calculate a hash for any set of data, finding data that is able to satisfy the specific requirements of the hash, requires vast numbers of calculations to find the right set.
While it is difficult to find the required hash value, verifying it is very simple.

  1. 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).

Collision resistance refers to the probability of 2 different sets of data calculating to the same hash. Because it is essential that the algorithm is unidirectional, finding 2 inputs with the same output will be catastrophic because it makes a reverse calculation possible.

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#3091
  1. Hash functions are one way functions where each input produces an unique output aka digital fingerprint.
  2. Hash functions in Bitcoins are using in mining for new transactions on the blockchain. The inputs for the hash function are the unique unconfirmed transactions plus additional data related to time and the previous transaction. These. Yay all be computed and added together and takes a lot of computing power to do so.

3.Collision resistance means two different input functions are unable to equal the same hash, or be duplicated

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#3092

  1. Hash function basically scrambles the input data in controlled manner, so even if that data is intercepted, it will be useless without the key.

  2. Hashing is part of mining process and miners responsibility. Hash functions are part of hash algorithm that is used to write new transactions in to the blockchain.

  3. Collision resistant, means that there are no 2 inputs that will give same output. This allows a trusted data integrity check.

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#3093
  1. Describe hash functions with your own words

a. It encrypts the input with an algorithm, which leads to a unique output serving as a digital
fingerprint.

  1. How are hash functions used in cryptocurrencies like bitcoin?

a. In bitcoin hash functions are used with an algorithm structure for data validation that are collision
resistant with computational efficiency and also have the ability to hide information.

  1. What does it mean when we say that hash functions need to be collision resistant?

a. In theory it should be extremely difficult to find distinct inputs that result in the same hash after
applying the hash function.

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