Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#5341

Homework on Hash Functions - Questions

  1. Describe hash functions with your own words hash function is basically like a “unique function” but more secure in a sence meaning once you create your own special word you will have a unique digital fingerprint asigned to it and its un reversible the input and output stays the same and in other words the only way of breaking that binary code is by basically switching a word that phrase but that would not make it the same hash function a hash function is known to be secured special function
  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). Bitcoin uses SHA-256 and RIPEMD160 whereas Ethereum uses the Keccak-256 hash function. They are primarily used for generating public keys and block hashing . Block hashing is a core concept of Bitcoin mining.
  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). In cryptography, collision resistance is a property of cryptographic hash functions: a hash function H is collision-resistant if it is hard to find two inputs that hash to the same output ; that is, two inputs a and b where a ≠ b but H(a) = H(b).
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#5342

It means that for two different inputs the output will not be the same. Every unique input should generate a unique output.

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#5343
  1. Hash functions are one-way functions which change input text to unique output.
  2. A hash function in Bitcoin is used to hash transactions in each block. Since each transaction has a distinct output the blockchain now becomes extremely secure.
  3. Collision resistant is where there must not be two different inputs that give the same output.
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#5344

  1. A unidirectional mathematical equation calculated using computers which generates a unique output from any given unique input. Creating an digital fingerprint that is unique to the original input.

  2. It is used in hashing transactional data and providing an “digital signature” for transaction.

  3. It needs to be very unlikely that two unique inputs will give the same output.

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#5345
  1. Describe hash functions with your own words

A hash function is a function used in the Bitcoin blockchain, where a certain input generates a one way output, that can’t be reversed. It generates a string of letters and numbers, through the most common SHA (Standard Hash Algorithm) 256.

  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).

There are many uses, for validating digital signatures, transactions and payments. It is a part of the consensus mechanism that the Bitcoin blockchain uses, which in this cas is PoW.

  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).

The basic definition of Collision resistance is that it is extremely difficult for 2 inputs to produce the same output, which is a key property of cryptography, and it’s nature in the Bitcoin blockchain.

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#5346

1. Describe hash functions with your own words

  • Hash functions are functions that you can input any value inside and it will output a random unique value that serves as a unique 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 are used in cryptocurrencies like bitcoin by serving as an identity for public keys and to avoid hacking by brute-force hashing.

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 each hash function must not be equal to any other hash function in existence. Each must be unique to avoid collision.
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#5347

  1. A Hash function is a mathematical process that takes input data of any size, preforms an operation on it, and returns output data that is totally unique to the input. It is a one-way function meaning it cannot to reversed engineered.

  2. They are used to create blocks in the blockchain as well as part of the underlying security of the application.

  3. That no 2 inputs result in the same output.

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#5348

  1. Hash functions are cryptographic functions that only goes one way, meaning each unique input (set of data) generates, throught a hash algorithm, an unique output (=hash, a deterministic random number, cryptographical result) that can’t be reversed back to the original input.

  2. Hash functions are central piece for Bitcoin/blockchains to work with the unique features they present, due to the characteristics of the cryptographic hash functions used in the system - in short: deterministic (~same input => same result), pre-image and collision resistant (meaning each input gives an unique output that can’t be reversed back to the original input and it is infeasible that 2 different inputs generates the same output/hash), puzzle friedly (, quick computation (~efficiency). The data is stored in a blockchain
    in blocks that are produced and linked to one another, respecting the consensus mechanism and data integrity checks using hash functions, from the Proof of Work consensus mechanism, from the block production to the addresses and transacions.
    A btc address for instance is derived from hashing a public key generated by a private key that is used to sign a transaction.

  3. Collusion is the rare case when 2 different inputs generates the same output (like if 2 different private keys generates the same bitcoin address). Rare because while it is not impossible,it is very very very hard to occur with the cryptographic hash functions tused in Bitcoin and other blockchains.

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#5349

1. Describe hash functions with your own words
hash is a mathematical method to produce fingerprints from an initial entry and cannot provide the same result in reverse or at least is not known or exponentially difficult.

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).
Bitcoin uses the sha256 twice; the result of hashing expects the lowest numeber and with 17 zeros in the result which make it very difficult.
Ethereum uses a hash function call keccak-256; which is similar to SHA3;

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 resistant in a hash functions is when it is hard to find two inputs providing the same result; f(x)= f(z)

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#5350

Answers:

  1. They are a type of function that provides greater security for data integrity, because a) each unique input produces a unique output, and b) You can go from Input to Output, but you can NEVER go from Output to Input.

  2. “Blockchains rely heavily on hash functions for generating cryptographic keys and hashing the transaction blocks.”

  3. “It means that for two distinct inputs, the output of the hash function should not be the same. So, mathematically, we can say that for 2 distinct inputs X1 and X2, Hash(X1) should not be equal to Hash(X2)”.

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#5351
  1. Describe hash functions with your own words

Hash functions are a form of cryptography that takes input data and hashes it into an output that is random and unique and serves as a kind of digital fingerprint. Once input data has been hashed into an output it cannot be reversed to find the original input data.

  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).

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.

  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 is when two different inputs produce the same hash output. It’s important that the cryptography used does not allow this to happen as it would compromise security and functionality of the blockchain.

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#5352

  • Describe hash functions with your own words

    They are functions that when a certain data set is input a unique data set is output. This is a one way function where one can always achieve the output from the input, but the input can never be calculated using the output.

  • 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 for mining and for verifying transactions.

  • 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).

We do not want the output of two different inputs to be the same.

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#5353
  1. Describe hash functions in your own words.

A function that takes a set of input of any random size and fits them into a data structure.

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

They are used for generating public keys to pass transaction information anonymously.

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

Property of a hash function that is unique in that it would take too many resources to compute making it unlikely for two inputs to collide.

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#5354

1.Describe hash functions with your own words

A hash function is a function that can be used to map data of arbitrary sizes to a fixed size value.

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 used in cryptocurrency to transmit transaction information anonymously. An example of the use of hash functions in cryptocurrency is Bitcoin which uses SHA-256 in its algorithm.

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).

This means that no two input hash functions should map to the same output.

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#5355
  1. It converts an “input” to a code made up of numbers and letters. The best hash functions(SHA-256) are impossible to reverse.
  2. Hash functions are used to pass transactions in cryptocurrencies like Bitcoin
  3. Collision resistant means that for every output, there is never more than 1 input
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#5356

1. Describe hash functions in your own words.
A hash function is any algorithm that takes an input of arbitrary length and produces a fixed length output. Outputs can be called hash values, hash codes, hash sums, checksums or simply, hashes.

2. How are hash functions used in cryptocurrencies like BTC?
Hash functions are used in cryptocurrencies to transfer information anonymously.

3. What does it mean when we say that hash functions need to be “collision resistant”?
A collision occurs when two keys are hashed to the same index in a hash table (so two inputs hash to the same output). When a hash function has more inputs than outputs, collisions will result. Collision resistance increases if it is more difficult to find two inputs that hash to the same output.

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#5357

  1. A hash is a one way function that provides or outputs a unique identification or fingerprint to an input source.

  2. For cryptocurrencies like BTC hash functions are part of the block hashing algorithm which is used to write new transactions onto the blockchain through mining and proof of work.

  3. A hash function being collision resistant indicates that it would be difficult to find two inputs that have to the same output.

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#5358

  1. Hash functions are a way to produce a digital finger print that is unique and unable to be reverse engineered.

  2. Hash functions are used in BTC and other crypto by using SHA 256 in the algorithm to record transaction data anonlymously on the blockchain. This creates privacy, but also transparency.

  3. Collision resistant means that an input in a given hash is designed in the algorithm to not produce a similar output. This can be weak or strong depending on the algorithm and how it is designed.

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#5359
  1. Describe hash functions with your own words: Hash functions take an input and product some unique output, that is one-way function.
  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 used to create public keys and block hashing.
  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 is very difficult to find 2 inputs that produce the same output.
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#5360

  1. It is a mathematical function with exponential complexity, same complexity applies in order to solve it.

  2. The hash function provides complexity in order to secure the phrase seed

  3. Hash functions require security against outputs attacks

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