-
Hash functions are mathematical formulas that have specific and unique computations determined by the input. The output of the hash function can not be used to determine the input, or at least that’s how it is supposed to work.
-
Hash functions are used in crypto such as BTC as unique identifiers to ensure that data is not altered in any manner. Any change to the input results in significant change to the outputs.
-
To say that hash functions need to be collision resistant is understood as the data cannot be accessed by those who should not have access. In order to prevent individuals from altering data, the output cannot be used to find the input.The hash function needs to be complex enough that each output of the function is like a digital/mathematical fingerprint.
-
A hash function is a mathematical function that converts a numerical input value into another compressed numerical value. The input to the hash function is of arbitrary length but output is always of fixed length.
-
In the context of cryptocurrencies like 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. 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.
In bitcoin mining, the inputs for the function are all of the most recent, not-yet-confirmed transactions along with some additional inputs relating to the timestamp and a reference to the previous block.
3.Due to the complexity and sensitivity of SHA-256, reversing the hash sequence in an effort to find the original input data is basically impossible. The difficulty of meeting SHA-256 means that this hash is extremely secure because it is“collision resistant.” Collision resistance expresses the likelihood of two different networks solving the same hash at the same chance is minuscule.
-
A one way of Input data to get a unique digital fingerprint as output. No way to go backwards from output to input!
-
In order to earn bitcoins throughmining, you need to put a huge amount of work necessary to solve a block and by earning that reward you are locking in all of the new transactions into the block, which is added to the permanent record.
-
By definition - strong collision resistance, the hash function does not enable finding Y given arbitrary X such that H(x)=H(y)
-
Describe hash functions with your own words
They generate a unique signature for representing a set of data
-
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).
By generating unique signatures to represent and chain 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).
It means no two hashs should ever be the same
- A hash function is a computer program that takes an arbitrary input containing an unspecified length of data, known as preimages, messages or input, then calculates a cryptographic output data bit of a specific length, known as digest, hash or output. The cryptographic nature of the ouptout makes it infeasible that the input could ever be deconstructed from the ouput - a ‘one-way’ funtion.
- Cryptocurrencies like BitCoin use algorithmic hash functions to encode its transactions. It is the encryption properties inherent in these functions the ensure the validity and security of the coin transactions. The hash function processes the arbitrary input of a transaction and creates an encrypted fixed-length output of it. These hashes are the (building) blocks that make up the entirety of the blockchain.
- Collision resistance refers to the possibility that two different inputs or messages put into the cryptographic hashing algorithm will create an identical digest or hash output. A well-designed algorithm must resist creating these duplicates as an avalanche of failure will result inside the blockchain.
-
Hash functions are functions that produce a unique output and cannot be reversed.
-
It is used in hashing transactions and mining.
-
It means that it is hard to get the same output in a hash function.
-
Hash functions are one-way functions in which every input creates a unique output
-
In the context of cryptocurrencies like 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.
-
Given two different inputs A and B where H(A) and H(B) are their respective hashes, it is infeasible for H(A) to be equal to H(B). What that means is that for the most part, each input will have its own unique hash.
[quote=“ivan, post:1, topic:8430, full:true”]
Homework on Hash Functions - Questions
-
Describe hash functions with your own words, A secret code way to rearrange any set of information so as the original input information can be verified but not known unless known from the input side. so a reverse of the information is not possible from only looking at an output hash
-
How are hash functions used in cryptocurrencies like bitcoin? the hash function is used to keep the key safe for the chain of UTXO, by not allowing anyone to reverse the hash of the private key, hashes are the language in the blocks that build this chain of transactions between the addresses, hashfunction as a language can only transmit information in one direction, and the origin of information can not be reversed be reversing the hash of the input information,
-
What does it mean when we say that hash functions need to be collision resistant?
Collision resistance comes from the ability that we can effectively reduce the probability of a collision of Keys for example with Bitcoin, which is actually impossible with Hashfunction sha 256, but as an example with a backup phrase of 24 words can have a larger number of wallets and keys and that some of the wallets could potential be unlock with a number of phrase word combinations.
-
A hash function is a function that takes an input and converts it to a specific value of a unique number of characters based on the Algorithm doing the hashing.
-
Bitcoin uses sha256 hashing in mining the previous block’s hash is needed to start the next block on the chain.
-
Collision resistant is preventing the likelihood of two items to have the same hash. Like having two differently keyed keys opening the same door.
Homework on Hash Functions - Questions
-
Describe hash functions with your own words
Hash functions convert an unique input into an unique output (which has always the same size) and is not reversable. -
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 also used in mining or to create public and private keys. -
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 means that 2 different inputs cannot produce the same output.
-
Hash functions means that when you insert an input you will get a unique output that is like a fingerprint. If you have this fingerprint there is no way for you to figure out the input. And if you change a single thing in the input you will receive a completely different output.
-
Hash functions in Bitcoin are used to write new transactions into the blockchain through the mining process.
-
A hash function is collision resistant when it is hard to find two inputs that create the same output.
- Hash functions are one-way functions that take an input of random length to elaborate an output of fixed length. Given the properties of the hash functions the output represents a fingerprint of the input.
- Hash functions are used in bitcoin to give an immutable fingerprint to every block and every transaction. They are also used for mining by hashing the previous block’s hash together with a randomly taken number called nonce.
- It means that two inputs A and B it must be infeasible to have the same hash so that H(A) = H(B). In other words we should be able to assume that if H(A)=H(B) --> A=B
A hash function is a function that allows a unique input to give unique output and it is infeasible to find the input through the output.
Hash functions are used in bitcoin mining, miners have to use inputs that start with 111000 to guess the hash target.
Collision resistant means if two different input give the same output and it will take a very long time for this to happen.
-
Describe hash functions with your own words
Is a function that when you put in a unique input, it will always produce a new unique output. No matter how little a change there will always be a new output. -
How are hash functions used in cryptocurrencies like bitcoin?
It is used in mining and transactions, giving them unique digital fingerprints that can not be altered. -
What does it mean when we say that hash functions need to be collision resistant?
A hash function is collision resistant if you put 2 different inputs and it’s hard to find the same output for both.
-
A hash function takes an input, performs an operation upon it, and produces an output. The input may be of any length, but the output is always of a fixed length which varies according to the type of hash function (e.g. MD5 = 128 bits; SHA 256 = 256 bits). The same input will always produce the exact same output, and changing even the slightest element of the input will produce a completely different output. A hash function is a one way operation, meaning that you cannot (easily) begin with an output and figure out what the input was. Given a particular output, one can theoretically perform a brute force attack in order to guess what the input was, but this will be very time/energy intensive.
-
a) A hash function is used in proof of work. Nonces are added to latest block & the resulting concatenations are hashed by miners until an output that begins with number of zeroes required by the current difficulty target is found.
b) A hash function is used to generate bitcoin addresses from a public key.
c) A hash function is used in creation and verification of digital signatures.
-
For a hash function to be secure it must produce outputs such that two different inputs cannot produce an identical output. When two different inputs produce the same output this is called a “collision”. Collisions undermine the security of a system that relies on the hash function.
- Hash functions take an input and encrypt it into an output.
- Hash functions are used to encrypt transactions, public keys and private keys on the blockchain.
- Collision resistance relates to the likelihood of 2 separate hashes being identical.
1/ Hash function transcode data input to specific output in 256 bit. Its imposible to reverse this proces so u canot get x out of y. it gives unique fingerprint to data
2/ Hashing transaction data
3/ it means you cannot get same hash code for 2 different things
hash functions are functions that can be used to take any input of arbitrary size and return a input that is fixed in size.
-
hash functions are used in cryptocurrencies like bitcoin for mining. New transaction data including timestamps, a reference to the previous block and arbitrary input data from miners is used to calculate a unique output.
-
hash functions being collision resistant means the inputs of any 2 hashes have an extremely low chance of generating the same output
Hash Functions are when you create an input it creates a “unique fingerprint” output that is only related to that specific input. No other data can create the same output as the input that was created.
Hash functions are used in cryptocurrencies like bitcoin in their Proof of Work mining algorithm. New blocks are generated by mining which requires hash functions.
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 such that H(a) = H(b), and a ≠ b. Every hash function with more inputs than outputs will necessarily have collisions .
-
Describe hash functions with your own words
A hash function takes an input and gives an output that is (as of now) impossible to brute force in a human lifetime. By giving an input into a hash function, the out put acts as a unique fingerprint in which if anything down to an individual bit of data is changed in the original input, it would give a completely different output. -
How are hash functions used in crypto currencies 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 the block header (it reads the previous hash from the previous block) and at the end of the block. Miners do this by hashing the transactions in a block with the hashed header from the previous block. Once they find the nonce, and are verified by others and accepted, it locks in the hash at the bottom of the block, that miners will use to verify in the next block. -
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 simply means that it is highly unlikely to generate the same hash from two different inputs. This is important because bitcoin relies on individual inputs creating individual outputs to guarantee its security.
Question for the community and or mods
Is this an statement an example of collision resistance in bitcoin ?
Statement- While theoretically it is possible to generate a wallet that already exists and holds the keys to an already existing wallet with existing input and output transactions, with current computational power the time require to do this would be eclipsed by the time the sun would supernovae and destroyed earth. So while it is theoretically possible, it is so improbable it is collision resistant?