Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#4279

1. Describe hash functions with your own words
Hash functions are one way computations where inputs of any size produce a unique output of a fixed size.
2. How are hash functions used in cryptocurrencies like bitcoin?
SHA256 is used to generate the numbers for mining blocks in BTC and providing confirmation of the proof-of-work.
3. What does it mean when we say that hash functions need to be collision resistant?
Collision Resistance is essentially a measure of the difficulty in hacking the hash function. They don’t resist collision altogether, but it has varying degrees of difficulty/resistance depending on the hash function.

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#4280

Each unique input produces unique output. We get a digital fingerprint. You can go from input to output, but you cant reverse it – to go from output to input. Hash function is a one way function.

Hash functions are part of the block hashing algorithm which is used to write new transactions into the blockchain through the mining process.

In a collision resistance hash function is hard to find two inputs that hash to the same output. If a hash function is not collision-resistant then an adversary can break the function with little effort.

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#4281

1.a hash function takes an input runs it through an algorithm and gives a unique output of a fixed length, which will be the same for any given input every time. An even slightly different input will give a totally different output.
2. in bitcoin the blockchain hashing algorithm is used to write new blocks. The input data relates to the most recent transaction and contains other data relating to the timestamp and the previous block plus pow data included by the miners
3. to be collision resistant each hash must be totally unique and not match ANY other, if it is possible to create the same hash with different data the function is not collision resistant

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#4282

  1. Hash functions are functions that take an initial input and in return create a unique “fingerprinted” output that cannot be used to figure out the initial input.

  2. Hash functions are used in cryptocurrencies like bitcoin when it comes to transaction data and the creation of new “digital stones” . The information based on previous input transactions has to correlate with the creation of new data and new transactions in result authenticating the data in real time.

  3. To be collision resistant hash functions must remain unique from one another and could not match another hash function. If the possibility of creating a hash with different data exists then the hash function is not “collision resistant”

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#4283

  1. Describe hash functions with your own words.
    It takes an input, does some math calculations and returns an output form which we can’t calculate the initial 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).
    It is used for block creation.

  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 input hashes should not have the same output hash.

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#4284

Hash functions are mathematical functions that convert an input of arbitrary size into a fixed length output

In Bitcoin, hash functions are used to write data into blocks through the use of miners.

Collision resistance in a hash function is when it is extremely difficult to obtain the same output with two separate inputs.

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#4285

A hash function is a one way digital fingerprint that is produced with a given input.

Hash functions are used in bitcoin to add blocks to the chain. Miners use computing power to solve increasingly difficult algorithms and create new blocks. If any changes are made into the the block or any previous block it is rejected by the network and not added into the chain.

Collision resistant means it is “nearly” impossible to get the same output with two different inputs

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#4286

  1. Describe hash functions with your own words
    Hash functions are one way functions, where each unique input creates a unique output or unique digital fingerprint.

  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 in Bitcoin are used in mining for new transactions on the blockchain. The inputs are unconfirmed (new) transactions including additional data related to time + previous transaction. Each transaction is unique.

  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).
    Collision resistance means that it is very difficult to find 2 inputs that produce the same output in a hash function.

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#4287

thanks for clearing that up

#4288

1.)Describe hash functions with your own words
-Hash functions are the technology on which blockchain was developed and involves using an algorithm to translate a set of data into an alphanumeric string of characters. More specifically hash functions are unique inputs that create unique outputs.

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 function are used in crytpocurrencies to keep data safe and secure. It does so by creating a unique string of code (hash) for each transaction. Hash functions are used to write new transactions into the blockchain through the mining process.

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 it is hard to find two inputs that hash to the same output. If hash functions were not collision resistant it would allow hackers to compromise the system.

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#4289

Describe hash functions with your own words

Hash functions are one way functions.

How are hash functions used in cryptocurrencies like bitcoin?

For creating addresses, private and public keys. Transforming transactions which can be recorded as hashes in a ledger.

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

It means that is hard to find 2 inputs that hash the same output.

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#4290

  1. Hash functions are a one-way transformable functions. Which takes an input and transform it into a unique output. Hash functions will generate a unique output for each unique input.

  2. Hash functions are used in a number of ways. Block headers are unique hashes. Wallet addresses are hashed version of your public key. Transaction id’s are unique hashes.

  3. Collision resistant means that a hash function should only produce one specific output given one specific input. A hash function should not be able to generate the same output with different inputs.

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#4291

1. Describe hash functions with your own words :

A hash function is a mathematical computation used to convert a string line of input (of any size) to an output (hash) of a fixed size.This hash can be seen as a digital fingerprint for the input data.

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

Hash functions are used in cryptocurrencies like Bitcoin to encrypt data when it’s being transmitted from one point to another to protect it from bad actors. Hashing is also used to authenticate data on the Bitcoin network.

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

This means that it needs to be infeasible or near impossible for two inputs to have the same hash/output.

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#4292
  1. Describe hash functions with your own words.

Hash functions are function that will always have a unique output with any unique input. Additionally, hash functions cannot be backwards engineered so that you can determine what the function is.

  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 mine bitcoin. If your computer fails to find an output value at or below the target, then the hash function will be completed again and again with a new input value until a successful output value is calculated.

  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).

If a hash function has a unique output for every unique input, then the function is completely collision resistance. There can be some inputs that compute to the same output, but the less this happens the more cryptographically secure the hash function is.

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#4293

  1. Its an encrypted function in witch you can’t go from output to input.

  2. hash function are used in the block hash algorythm. its used to write new transactions into the network by mining.

its mean that it should be very hard to find two inputs who makes the same output . the more difficult this is the safer is the network.

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#4294
  1. Describe hash functions with your own words
  • A hash function is any function that can be used to map data of arbitrary size to fixed-size values. The values returned by a hash function are called hash values, hash codes, digests, or simply hashes. The values are usually used to index a fixed-size table called a hash table.
  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).
  • Bitcoin is a chain of digital signatures (outputs from hashing function) that reflect the coins path through the Bitcoin ecosystem.
  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” means that is computationaly hard to find two different inputs that would produce one and the same hash digest. It is not impossible though.
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#4295

  1. A hash function uses cryptographic algorithms to take the input of an arbitrary length and converts the data to a unique output of a fixed-length hash. The “bitcoin hash”, SHA-256, produces a 256-bit hash value and is usually represented as a hexadecimal number of 64 digits. Hash functions are an irreversible one-way function, therefore the input and only be recovered through brute force, which is extremely rare and nearly impossible.

  2. The bitcoin algorithm and protocol involves writing new transactions on the blockchain through mining. For this they use hash functions, they are secure and show the proof of work. The hashing algorithm writes the new transactions, which verifies and makes it irreversible

  3. Hash functions need collision resistance to warrant the singular identity. Without collision resistance its more probable that two different inputs will give the same output. Collision resistance does not claim to make collision impossible, just very unlikely

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#4296
  1. Describe hash functions in your own words

Hash is when data is entered into a hash algorithm such as SHA-256 and hash to produce an output that is unique to only that data that was input. This hash output data is the fingerprint for the input data.

  1. Hash functions make up the blockchain in Bitcoin and these hash algorithms are used to write new transactions and provide security for cryptocurrencies like Bitcoin.

  2. Hash functions need to be collision resistance means that two different inputs into the hash algorithm must not give the same output or fingerprint. Therefore, failing to find two inputs that give the same output means that the hash function is collision-resistant.

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#4297

  1. Encrypt input into a 1 to 1 mapping random string.

  2. hash set of transactions into a block and hash with previous block

  3. Hash function needs to generate a very long random string in order to reduce the possibility of having different input generating a same output.

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#4298

  1. Describe hash functions with your own words.
    A hash function consists of mathematics calculations and it takes in variable size input, process it, and produces fixed size output.

  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 function is part of block hashing algorithm which is used to write transactions into blockchain through mining process.

  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 so that the outputs from various inputs will not be the same.

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