- Hash functions enable the generation of values from a string of text
- Hashing functions in bitcoin take transactions as input and run through a hashing algorithm to give an output of a fixed length
- hash functions need to be collision resistant so that inputs will have their own unique hash.
- a function that transforms an input into a fixed lenght output. it should be impossible to get to the input only knowing the output. the output is a fingerprint.
- itās used in mining. miners try to get the same block hash through trial and error. they are ahshing the components of the block to get the right block hash.
- that each uniqueinput creates a unique output (hash).
- A unique (one way) digital fingerprint that takes data of any size and returns a fixed length
- SHA-256 is used and used in such a way that āhey thereā produces the same sized output as āthe rain in spain stays mainly on the planeā.
- Each input has its own unique hash BUT its not collision free. It would take brute force for two inputs of like output to collide. And take so long that it wouldnāt matter.
What do you mean? Hashes are fixed length by default and if they would get the same hash, that would mean they would break collision resistance, which wouldnāt be good at all.
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Hash functions are one way functions that take and input of varying length and return an output of a set length. The same input will always output the the same value.
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Hash functions are used to encrypt data and sign transactions in cryptocurrencies like bitcoin.
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What it means for hash functions to be collision resistant is that using brute force to guess the input value at random for a given output should rarely produce the correct value. The odds should be so high that it is infeasible for any modern system to guess it in any reasonable amount of time.
- A function is a computation that has both an input and and output. The input will change what the output will be. A hash function, is a function that all ways produces an output of a certain length. Because of the convenience of having a deterministic output of a function, both in the length of the output and deterministically produced from the input, it can be used to verify that the input is the correct input that is sought. This can be used to verify the contents of any set of data, that that data is the original data that produced the hash functions output. This can verify that the data has not been changed, such as with a message or a program, or it can be used to verify unknown data, such as when it is used to very the signature of a private key.
- Hash signatures are used in at least two ways in bitcoin. One way is that it that the hash signature of the previous block in the bitcoin blockchain is added as a part to every new block. This is essential in making an immutable, append only, chain of data, which in this case is an account of transactions made. The other way that hash functions are used is identity verification. Each transaction must be signed using the private key that controls the transaction made using the public key. This verifies that at the very least the transaction has been made by someone in possession of the true private key. It does not guarantee that they successfully protected that private key, or the true identity of the person using that key. It only verifies that the private key itself, which was used in the transaction, is the true key that controls the bitcoin that is held in the blockchain ledger which uses its public signature. Also the difficulty of finding a key to match a hash signature is used to slow down the appending of the bitcoin ledger by creating new blocks, which node users are incentivised to āmineā. The time it takes to find the key that will produced the nonce by hashing the new block, slows down the addition of new blocks so as to not cause to many blocks at once being sent to the network. The miner is rewarded with bitcoin for using the computational power that they posses, to create this new block. The block is then sent for verification against the ledgers spread throughout the P2P network. Any fake block will be rejected, wasting a miner, who tries to be malicious to the networks interest in creating an accurate block of ledger data, time and computing power.
- Collision resistance simply means, that the algorithm used to produce a signed output from a private key, is very unlikely to produce that same output from a different private key. It is in theory conceptually possible, for there to be, algorithms which have collision resistance, such that it is virtually impossible for two private keys to be found that can produce the same signature. It is also however conceptually impossible to have any signature of a shorter length than the private key that is completely impossible for two private keys to exist that could produce it. It is just a matter of the extreme odds against it that secure data or identity, using a private key. One has to wonder with the advance of technology, Mooreās law and the seeming advent of quantum computing, if this will all ways be the case.
A hash function is a unique output (fingerprint) for any input, any changes to input creates a new hash.
Hash functions are used in bitcoin to write new transactions into the blockchain through mining. Hashes are also used for wallets public and private keys and passwords.
Hash functions need to be collision resistant in order to keep output hashes unique to their respective input, while itās still possible for collision in SHA-256 it is less likely for collision to occur
1. Describe hash functions with your own words
It transform your enormous data to a āsimpleā hash, if you change something, even a dot, the output transform to a different 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).
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 and verify transactions in bitcoin.
3. What does it mean when we say that hash functions need to be collision resistant? (We didnāt use the term ācollision 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, thatās how you learn best).
Collision resistant means that it is hard to find two inputs that have the same hash output,
Collision resistance does not mean that no collisions exist; simply that they are hard to find
- Describe hash functions with your own words
Hash functions take input and create an output of fixed length specific to the input.
- 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 include data input into the blockchain of cryptocurrencies such as bitcoin. This helps condense data to be suitable to fit in a block.
- What does it mean when we say that hash functions need to be collision resistant? (We didnāt use the term ācollision 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, thatās how you learn best).
From all the possible inputs and limited output there is a chance that two different inputs could create the same output. Collision Resistance is critical to ensure this is as rare as possible otherwise can corrupt the chain as too many opportunities for data output to get confused with something it is not.
Hash functions are not used in the creation of public keys. For that the elliptic curve is used.
Hash functions are not used to derive public keys. For that an elliptic curve is used. Hash functions are important to link the blocks in a chain
- one way function than creates unique output
- in bitcoin we use SHA256 and it creates unique 256 symbol output no matter how big or small is an input
- it means when all data blocks connected in a chain, we don`t want to have an identical hash
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Hash functions are functions with a complicated hash to add security.
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They are used to by encrypting the input to output, requiring massive processing power to solve.
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Collision resistant means that different inputs wonāt generate the same outputs.
a hash function is a function that generates a hash. A input give like a fingerprint output
Bitcoin uses sha 256. the input gives a specific output and same input will always give the same output but even a small change in the input will change the output totally. For now the output canāt be reversed to the input. If someone finds away to do that, then bitcoin is doomed!
to be collision resistant means that there is a need that different inputs will not give the same output if to outputs comes out the same then its a collision.
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A regular function you can determine the input from the output. With a hash function secured with a hashing algorithm like SHA256 it is infeasible to determine the input based solely on the output.
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Pointers and Lists are used to compare hashes and continuously build blocks. Once the hash is found that exceeds the difficulty level set, then a new block is created and rewards sent to the miner that found the unique hash.
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Collisions on a network will cause drops in traffic. In hash functions if they are the same I imagine it will cause missing data when a miner thinks he got the reward and he in fact did not. That is why a new block is made every 10 minutes rather than every 15 seconds. To avoid these types of collisions.
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Each unique input gives a unique output. Hash functions take an input and put out a 16 bit hex string.
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Hash functions are used in bitcoin for transactional data as well as plain text. The data is encrypted to a 16 bit hex.
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Collision resistance is the inability to have the same output (fingerprint) from a similar input.
Collision in a hash function means the likelihood of two inputs resulting in the same output.
Its 256 bit, hex is jut most commonly used encoding to display these numbers
Iām glad you said something. I was thinking characters rather than bits.
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It is a deterministic function that gives same length output from a specific input but it is infeasible to figure out from the output what the input is and to have the same output from two different inputs.
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Hash functions are used in mining to confirm a transaction. The miners have to guess the input that produces a specific output that is linked with the previous hash (block id).
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If a hash function is collision resistant then if H(A)=H(B) it is secure to say that A=B.