Homework on Hash Functions - Questions

[efuentes]

Homework on Hash Functions - Questions

1. Describe hash functions with your own words
   A hash function allows you to securely obtain an output using an algorithm that does not allow you to know 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).
   Hash functions are used to validate that transactions in a block are accurate and valid.

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).
   The hash function should use an algorithm that makes it extremely difficult, or virtually impossible, to find 2 different inputs that would give the same output.

[UDAYJADI]

1. Hash functions are that give a unique output when given it any input

2)Hash functions are that is used in crypto is used to generate the public keys

3)collision resistance is that there is no two inputs that produce same output in hash

[Nurka]

1. Describe hash functions with your own words
   Hash is a coding that takes inputted data and decodes it using numbers and letters as output.
2. How are hash functions used in cryptocurrencies like bitcoin?
   It is used in cryptocurrencies to run its consensus mechanism.
3. What does it mean when we say that hash functions need to be collision resistant?
   Hash function collision resistance is when it is hard to find two inputs that hash to the same output.

[Eternalx]

1. Hash functions are types of functions that takes in an input and gives an output depending on the difficulty of the block that the person is trying to hash, so it can be solved to unlock the next block.
2. They are used in BTC by keeping the coins secured on their trusted function sha256, since the hash rate and difficulty to hash is already significantly high.
3. When a function needs to be collision resistant. It means that there cannot be two different types of inputs that can give the same output answer.

[Marta_Tofan]

1. Hash functions generate unique keys. Any small modification in input will completely change output. In that case any changes can be easily defined. In the hash functions we can go from input to output, but never reverse the way. In case it happens Bitcoin might be broken.
2. They are primarily used for generating public keys and block hashing. Block hashing is a core concept of Bitcoin mining. In this process, a block of unconfirmed transactions is fed to a hash function and a hash digest is generated.
3. 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). … ) hash operations on random input is likely to find two matching outputs.

[BalancedBaldy]

1. Hash functions can be described as one way functions that have a unique input and put a unique output and is extremely difficult if not impossible to reverse.
2. Hash function are used in cryptocurrencies by miners for transactions on the blockchain they use unconfirmed transactions along with other information as the input to get unique output that cannot be reversed.
3. What is meant by hash functions need to be collision resistant is that two inputs should not produce the same output in a hash.

[christop242]

1. Describe hash functions with your own words
   a hash function is a process with a set of steps governed by predetermined rules that will take an input and produce a unique output value that cannot be reverse engineered to find the original input data.

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 by miners to prove that through a lot of time(in computing terms) and computing effort, they have successfully solved a mathematical problem and created a hash (produced a unique out) of a particular size that proves they did ‘work’ (proof of work) on the input, which is a combination of hashes from previous blocks on the blockchain as well as other pieces of information. When this is done, the first miner has (won the right to add another block to the blockchain?).

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 simply means that 2 two unique inputs can not produce the same unique hash function output.

[ellieD]

1. Describe hash functions with your own words

A hash function receives an input and provides an output as a fixed length digital representation, regardless of the input size. Making any change whatsoever to the input will result in a wildly different 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).

Confirming transaction accuracy in mining proof of work.

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).

The protocol would be vulnerable if two different inputs resulted in the same hash output.

[North2L]

A function or procedure that generates a fixed-length bit string without any regularity from an arbitrary-length bit string.

Hash functions are used for digital signatures and mining legitimacy.

The hash function is collision resistant if it is difficult to find two inputs that hash to the same output

[Abel]

1. Describe hash functions with your own words

it is a cryptographic function that for each input it will give you an unique 64 digits Hexadecimal number.
They are one way function, it is computationally cheap to calculate the hash of and input but it is really hard or near impossible to figure out the input from the 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).
The hash functions in bitcoin are used to link together the blocks, to create the block chain and also they are used in the mining process, the miners have to guest the nonce that together with the block it gives a value below the target.

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).

A collision ocurres when you get an identical output from two different inputs. using the SHA-256, this has a likelihood of 2^256 , and it is considerer good enough. ( it is a bigger number than atoms in the universe)

[MariaPetronela]

1. Hash functions are functions that convert strings of different length into fixed-length strings. A hash function scrambles data and converts it into a numerical value. And no matter how long the input is, the output value is always of the same length. The output values cannot be inverted to produce the original input.

2. Within the Bitcoin ecosystem, the hash function provides security and is used in two areas:
   • creation of the address
   • mining (Proof-of-Work)

3. A hash function is collision-free when no two strings can map to the same output hash (every input string must generate a unique output string).

[cryptocashin]

1. Hash Functions are unidirectional algorithms that provides a unique output for a given input.

2. Hash functions are used in bitcoin by providing a way to give ownership to each wallet address. This is accomplished by having the public key represent the “input” and the private key represent the “output”.

3. Having a collision resistant hash function means that the function exists in a way that no 2 inputs can create the same output. This is important to guarantee users that someone with a different public key then you wont be able to access your funds by having your private key.

[shadowfaz16]

1. Describe hash functions with your own words
   functions that encrypt data into 256 bits and can’t be deciphered (reversed) to find the original data.

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 bitcoin, hash functions encrypt data and blocks are formed. in order to form a new block, you need the hash of the previous block together with transactions and a nonce (number) to create the hash of the new one.

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).
   a collision resistant block menas that even though number 1 and number b are different, they might produce the same hash, so hash functions have to be collision resistant which makes this very very difficult.

[MilanC]

1. Hash functions are a function where each unique input has a unique output. when a hash function is used it puts the data in to alphanumeric sequence where the output cannot determine the input.

2. hash functions are mainly used in other crypto currencies for generating public keys and block hashing.

3. collision resistance means that it is very hard to find two inputs with the same output.

[_Vincent]

1. Describe hash functions with your own words
   This is a function taking a unique input to produce an unique output. It enables to store in a little part of data a value, file, media, etc … very big at the beginning. The size of the output can be various (64, 128, 256, etc…).
   With the output, we cannot retrieve input 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).
   Because Bitcoin blockchain is a great big digital ledger, a hash function enables to encrypt this ledger, a part of this ledger in a little size of storage in each block.

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).
   When two distinct inputs, for a hash function, give the same output : this is a collision.
   A hash function need to be collision resistant in order to prevent that someone is able to find easily another input with the same output.

[AlexanderLeyland]

Q1. Describe hash functions with your own words
A. Hash functions produce a large, unique number (hash) for a given input in such a way that the original input cannot be discovered by the output.

Q2. 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 functions produce the digital signatures for each block in the Bitcoin blockchain. ‘Mining’ is the process by which the hash is calculated for each block, confirming it and adding it to the chain.

Q3. 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).
A. ‘Collision resistance’ refers to the ability of a hash function to produce hashes in such a way that it becomes impossible for two inputs to produce the same output. Hash functions work best when they produce completely unique hashes, similar to fingerprints.

[Davewick]

1. Hash functions are a function that can change an input into a unique output, that should be impossible to reverse.

2. Hash functions are used in cryptocurrencies to take an input of varying lengths or data and output it to a fixed length, with a unique makeup. Hash functions are used as it adds security to the transactions. Hash functions can also not be reversed.

3. Collision resistant means that no 2 hash inputs will produce the same output, unless it is an identical input.

[bvtran]

1. Hash functions take any unique input and give out an encrypted unique output. Another important characteristic of hash functions is that they are one-way functions where you can insert an input to get an output but you can’t reverse-engineer it to pull in an output to get the original input.

2. Hash functions can be used to secure private keys to people’s wallets and passwords to accounts. Since hash functions produce unique outputs, anyone without the correct password/key won’t be able to access the account; ideally the rightful owner will only have access. In terms of mining, the hash function is useful in verifying transactions before they added to the blockchain. Miners must find the correct nonce to input to produce the desired hash before being awarded BTC; incentivizing people toward honesty rather than attacking the blockchain.

3. Hash functions need to be collision resistant, meaning that they are unlikely to produce the same output for two different unique inputs. This is important because if there is no resistance, it becomes easier for an attacker to figure out the inputs for a repetitive hash, resulting in undesirable scenarios (e.g. lying that they computed enough times to find the desire hash in mining or faking a digital signature on some contract that the actual party did not agree to).

[chiranjivi_patnaik]

1. An algorithm for each unique input it will produce it will produce unique output.
2. They are used to create keys and block hashing.
3. Collision resistant- If two input are different than there hash function always be diffrent.

[Scott815]

1. Describe hash functions with your own words
   hash function take input and put through and outputs to a unique output of sha256

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 part of the mining process and the blocks are put through the hash process and checked and then written to the blockchain and way of checking information is correct.

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 mean that two inputs into a function will not get the same output.