Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#4961
  1. Describe hash functions with your own words;

A hash function is a mathematical function that converts a numerical value (input) into another(output) numerical value, aka hash. The hash represents the original numerical value (input).

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

Hash functions are 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?

Collision resistant means it should be hard to find two different inputs of any length that result in the same hash.

1 Like
#4962

  1. Describe hash functions with your own words
    Functions that can only take an input and provide an output with the characteristics of the input, but not the other way around.

  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 during the mining process of creating a coin.

  3. What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best).

It means when it is hard to find two inputs that hash to the same output. Without this being true, the function can be easily broken if attacked.

1 Like
#4963

Describe hash functions with your own words:
Hash functions are mathematical equations that are designed to produce a unique output known as the hash / fingerprint. The fingerprint is created by inputting a series of unique data into the function. If the input data were to be changed or altered, in any way, it would then produce a completely different result as the output.

How are hash functions used in cryptocurrencies like bitcoin?
Hash functions are used in cryptocurrencies like Bitcoin as way for a given miner to prove to everyone else on the network that they have indeed processed the transactional data correctly. Hash functions are used to solve the ā€˜puzzleā€™ and claim validation for that block of data. The only way to do this is to run through a huge number of possible values, until the required output hash value is found.

What does it mean when we say that hash functions need to be collision resistant?
A hash function has to be collision-resistant to ensure that it would be near impossible for two different inputs to produce the same output.

1 Like
#4964

1. Describe hash functions with your own words.

Hash function sets data input with a unique output, it is a one way-way mechanism gauranteed through mathematical equations. It does not allow reversal of a new hash, meaning you cannot use the output to figure the 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).

Bitcoin and other cryptocurrencies uses hash functions that also utilizes proof of work combined with SHA-256 to obtain mathematical traceability and unbreakability. For every input, it produces a unique output, gives the computation fast, cannot be reverse and can only be solved in a linear undirectional manner.

3. What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best).

It means a hash function is collision resistant if itā€™s hard for 2 inputs to hash the same output.

1 Like
#4965

1 . Hash functions are inputs that produce a unique output that can not be reversed. The output produced is a digital fingerprint.
2 . The hash function is used in bitcoin to convert all the information in the transaction into a hash that will be added to the block.
3 . Saying that hash functions need to be collision-resistant means that it is difficult to find two inputs that produce the same output.

1 Like
#4966

1-Hash functions are fingerprint generators and with each of every input, a hash function generates unique encrypted string.
2- Hash functions are part of block hashing algorithm in cryptocurrency like BTC. Its use is writing each new transaction in the blockchain consensus at the moment of the process of mining. The body of the block contains the transactions.

Source: https://www.coindesk.com/markets/2017/02/19/bitcoin-hash-functions-explained/
https://en.bitcoin.it/wiki/Block_hashing_algorithm
3- The character limit of encrypted string may cause collision because the data length before encryption differentiates while the lenght of the encrypted code remains the same. It sometimes may cause the same crypted string for different noncrypted data.
Source: https://www.lifewire.com/cryptographic-hash-function-2625832

1 Like
#4967
  1. Hash functions are encrypted one way functions where a unique input gives a unique output or fingerprint.
    Which cannot be reversed to find the original input.
    2.hash functions are used in BTC to hash the transaction data which miners compete to verify and secure to receive rewards for there work.
    Proof of work.
    3.as each input creates a unique out put it is computationally unlikely to get two inputs arrive at the same output thus making the hash function collision resistant.
1 Like
#4968

  1. Hash functions are inputting information and resulting in a digital alpha numeric fingerprint in the output that cannot be reversed to figure out the input.

  2. Hash functions are used to transfer data or transactions from user to user anonymously.

  3. Meaning that two different inputs will never result in the same output.

1 Like
#4969
  1. Hash functions are math formulae that generate a fixed size output from a variable size input.
  2. cryptographic hash functions are used in cryptocurrencies like bitcoin, it uses the SHA-256 hashing algorithm which only produce outputs of in 256bits (64 characters) regardless of the input size.
    3.Collision resistance is a property of Cryptographic Hash Functions, it means its infeasible
    to find any two inputs that produce the same hash output.
1 Like
#4970

  1. Hash functions are similar to functions except to the fact you cannot go from output back to input.

  2. Hash functions are used to secure the bitcoin network

  3. It means that it is extremely difficult to find two inputs that can hash to the same output. Every output is unique.

1 Like
#4971
  1. Describe hash functions with your own words
    *Hash functions are digital fingerprints created with input data that create unique output data. No two outputs are ever the same.
  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 hashing to write new transactions to the blockchain through mining. These hash functions are non confirmed transactions with relative information such as timestamps and their relation to the previous block.
  3. What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best).
    *Collision resistant hash means that it is difficult to find two inputs that hash the same output.
1 Like
#4972
  1. Hash functions are the process by which input becomes cryptographically secured using a hashing algorithm such as SHA256
  2. Theyā€™re are used to challenge miners to validate blocks and reward the miners that can solve hash problems with Bitcoin - Proof of Work
  3. A hash function is collision resistant if it is difficult to find two inputs that create the same output
1 Like
#4973

Describe hash functions with your own words

ANSWER:

Hash functions are the irreversible or one directional result receive for any given input function.

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).

ANSWER:

Hash functions are widely used in cryptocurrencies to pass transaction information anonymously.

Hash functions is used to write new transactions into the blockchain through the mining process .

They are also used for generating public keys and block hashing .

What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best)

ANSWER:

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

1 Like
#4974

  1. Hash functions are a sort of codification of data that occurs by converting a piece of code (text, numbers, images, database information, matrixes, etc) into a unilateral encrypted output that cannot be checked with the initial input or raw data. By creating a new hash, it gives a new printer-mark with a fixed length to the initial input that can be added to a blockchain that meets the conditions of the new hash.

  2. A hash function for BTC starts by encrypting new sets of random-size data (transactions) into a fixed-length code (hash). Then, this data is added to the header block where the PoW has to be made by solving a piece of code of block in the algorithm. In order to reach a solution, the miner has to find a solution for the chosen nonce that can be reached when the new hash is less than or equal to the target hash. By solving the code, the miner gets a reward and the encrypted/validated information is added into the blockchain.

  3. It means that two different inputs mustnā€™t have the same hash output to ensure security in the blockchain. A cryptographic hash collision is considered a threat for the encrypted information because it might give some hints associated with the input used to create a hash. Thatā€™s why a strong collision resistance (the singularity in each new hash) is needed in the blockchain.

1 Like
#4975

They are special functions, each unique input will give a unique output which is infeasible to reverse.

To protect transactions / BTC miners use hash functions to mine blocks

collision-resistant means that the algorithm is never creating an identical hash from two or more transactions at the same time

1 Like
#4976
  1. Describe hash functions with your own words

A unique digital fingerprint represented as encrypted code that gives a unique output.

  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 uses hash functions in order to create new blocks through minining and verify each unqiue transaction that takes place using SHA256.

  1. What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best).

Each input has itā€™s own unique hash with no chance of of it resulting in the same output twice.

1 Like
#4977
  1. Describe hash functions with your own words:

It is an almost unique fingerprint representation of an specific size that results from data input of any size that canā€™t be reversed. Any slight change in the input gives a completely different result for output.

A hash function takes an input of information and converts it into 256 bits,

  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 bitcoin hash functions are used as part of a protocol to save transactions, the inputs of the hash functions are the most recent transactions which havenā€™t been confirmed, complemented with additional automatic inputs like the timestamp and a reference to the previous block. This information is combined by the miners trying to get a result starting with certain number of zeros, if more zeros are required on the beginning of the hash the computation that has to be done is more complex (I assume it is because the structure of the hash is more defined).

The input that makes reference to the previous block makes it very difficult to modify something already written in a previous block because any slight change would modify the result of a previous block hash and it wonā€™t fit with subsequent block references.

CoinDesk: Bitcoin, Ethereum, Crypto News and Price Data

  1. What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best).

Being collision resistant in cryptography means that it is very hard to find 2 inputs that hash the same output.

Collision resistance - Wikipedia

1 Like
#4978
  1. hash function is in which there is only one way same and unique out put but cant be reverse for output to input.
#4979

  1. Hash functions take a given input, put it through a complex algorithm, and produce a base-16 output, called a hash, which cannot (currently) be reverse-engineered to find the initial input.

  2. Hash functions are used in mining new bitcoin blocks. The bitcoin protocol sets a target output number, and each miner has to guess random inputs in an attempt to produce an output lower than the target output. This guesswork is repeated until a mining computer finds one of the lucky inputs. The one-way street aspect of SHA-256 cryptography is what forces miners to do immense amounts of computing work to guess the correct input, while conversely allowing immediate verification of it by validator nodes once a correct input is found by a miner.

  3. This was pretty technical, but it seems like a collusion-resistant function is one that has very very very FEW different inputs that can give the same output, which makes it very very very unlikely that a bad actor will find another input that can achieve the same output and thereby forge a digital signature. I may be off on this, happy to find out more later.

1 Like
#4980

  1. A hash function takes an input, converts it to binary, and applying different maths, creates an unique output which (currently) cannot be used to get the original input. So this is one way operation.

  2. Hash functions (SHA-256) are used in Bitcoin to grant security in the network and making PoW possible.

  3. Collision resistan means that two different inouts should not create a same output, which would compromise the security of the function.

1 Like