Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#1022
  1. Describe hash functions with your own words

A hash function is a mathematical function that converts a numerical input into another compressed numerical value. These values that are returned by a hash function are called the message digest or basically the hash values.

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

The bitcoin protocol uses hash functions as part of the block hashing algorithm which used to write the new transactions into the block chain through the mining process.

  1. What does it mean when we say that hash functions need to be collision resistant?
    Collision resistance is property of cryptographic hash function. Collision resistance does not mean that no collisions exist; simply that they are hard to find. Essentially meaning that two of the same inputs would unlikely ever create the same output.
1 Like
#1023
  1. They are “one-way” functions. Given a unique input you get a unique output.
  2. Blocks are hashed and the network verifies the data integrity of each block according to the hash generated.
  3. You cannot have different inputs generating one same hash.
1 Like
#1024
  1. Describe hash functions with your own words- Hash functions are one-way functions that have a unique input for every output and are used to create a finger print of a collection of data.
  2. How are hash functions used in cryptocurrencies like bitcoin?- When miners are mining for bitcoin they are looking for an input that will produce a match to the given output. Hash functions are also used to hash financial transactions and user addresses.
  3. What does it mean when we say that hash functions need to be collision resistant?- Collision resistant means the function has a very low chance of finding two inputs that hash into the given output. This is important because two sets of data should not have the same hash.
1 Like
#1025

  1. Hash function is a formula which gives one time finger print output to given input. Unlikely to traditional functions, Hash function output will not allow to find input. It is used as data integrity check.

  2. Hash functions are used for verifying the integrity of messages, and files, verification of password, generation of digital signature and verification. This will allow registering correctly the transactions in order to avoid duplicating. This is also used in mining.

  3. Collision resistant means it is very hard to find 2 inputs that will hash to the same output. Collision attach is brute force attack to randomly try the numbers to resolve. Some Hash functions believed to be collision resistant in the past were broken. SHA-1 and MD5 by much easier techniques than collision.

1 Like
#1026

1.) A hash function is a function that takes an input and produces an unique output; an analogy of the human finger print. This input / output is consistent so as Input X will always equal the unique Hash Output. This process is one-way though, and is near mathematically impossible to reverse engineer so as to ascertain the original input via the hash output.

2.) Hash Functions by themselves represent an important part of security and protecting the information (i.e. the original input) from being discovered. Within Cryptocurrency Hash Functions continue to serve this security function, but also part of the algorithm responsible for writing new transaction to a block chain by mining.

3.) Collision Resistant means to decrease the probability that two unique inputs might result in the same hash function output. This would be problematic to say the least.

1 Like
#1027
  1. A hash function transcripts a text input into an output code
  2. Hash functions are used in the block mining process. Blocks are connected by containing the prior blockhash.
  3. Every hash input will have a unique output - by that avoiding collisions
1 Like
#1028

  1. Describe hash functions with your own words
    from a unique input i obtain a unique output which is a string.

  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).

for any transaction is created its hash

  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 hashes of two different input are “almost” always different

1 Like
#1029

  1. Describe hash functions with your own words. A hash generates value from an input with a unique code.

  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 run through ( SHA-256) algorithm which gives an output of a fixed length, instead of remembering the input data, you can just remember the hash.

  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).

Each input will have its own unique hash.

1 Like
#1030
  1. Hash functions are a set of unique code fro an unique input which allow for information to travel safely.
  2. hash functions are used to write new transactions into the block chain through the mining process. it is the need for large processing power that new bitcoins can be get mines over a longer period of time and not immediately.
  3. collision resistant mean that it makes it harder to find the inputs that create the output. which in turn makes the code hard to crack.
#1031
  1. Something that takes an input and outputs a hash/fixed length output.
  2. Bitcoin is a digital ledger of hashes that use proof of work along with SHA-356 to obtain mathematical traceability and unbreakability. Very important in mining bitcoin.
  3. Each input will have it’s own unique hash, for the most part. Although it is easier to break than pre-image resistance because of the birthday paradox concept.
#1032

Describe hash functions with your own words
Has functions are functions where given the same input, the output is unique. Furthermore, they are considered to be “one-way” functions in the sense that given the output, we cannot deduct the function’s input.

How are hash functions used in cryptocurrencies like bitcoin?
Hash functions have a purpose of verifying data. Some cryptocurrencies like Bitcoin use the SHA-256 hash function, though other functions are available (SHA-1, Streebog, MD5, MD6, etc).

What does it mean when we say that hash functions need to be collision resistant?
It means that they need to be hard to find the solution for, for security purposes. Basically two inputs will not “collide” with their hash function output by being the same.

#1033
  1. Hash function is one-way function that take an input, making mathematics calculation, and giving a specific output valid only for that input.
  2. Hash function used in bitcoin, the input is a transaction data. Mining and finding a nonce requires finding a number that generates a specified hash in combination with data unique to that block.
  3. Collision resistant means two different things are not getting the same hash.
#1034

  1. Hash functions, it is special functions , when you insert something and you get a unique finger print. If you change something in hash function, that finger print changes completely.

  2. 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.

  3. 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.

#1035
  1. Describe hash functions with your own words

Hash Functions is the solution to encrypting information, by securing the data so its almost impossible to find the input, and it also ensure data integrity so we can see if something has been changed.

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 and other blockchains, HASH functions are used to first encrypt an input of transactions (unless the wallet is public). It is used in mining since it is needed to solve the puzzle to unlock bitcoin. It can be Very Public or Private when its needed.

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, just means that we should not have more then one of the same Hash output for a different input. It can happen, but it is so insignificant it is not an issue.

#1036
  1. Describe hash functions with your own words
  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).
  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).
  1. A one way function with a fixed length digest.
  2. Each block on the blockchain is turned into a hash, which is then stored as the block header in the next block. This makes it so that any attempt to change the data in a block results in a complete change to the hash connecting the previous blocks, and shows a break in the chain.
  3. Collision resistance is important because the more likely you can generate the same outcome from different inputs, the more susceptible it is to exploitation.
#1037

  1. Hash functions are one way functions, in which each input generated a unique outlook; a digital fingerprint for the input.

  2. Bitcoin hash functions is used on transaction data and mining programming operation.

  3. Collision resistant means 2 input will have the same output.

#1038

A hash function establishes a unique alphanumeric key to identify specific data structures (regardless of type or size) using an algorithm. The digital key cannot be reversed to reveal the data structure, but the data structure will always output the same key as long as no changes were made to the original data.

Hash functions are used in crypto like BTC to input transaction data from the network into the hashing algorithm, resulting in confirmed transactions.

Hash functions needing to be collision resistant means that the likelihood of two separate, simultaneously competing inputs should never have the same output. So the hash function should always have more variation in outputs than inputs.

#1039

QNS 1. Describe hash functions with your own words
Hash functions are one way function, where each input generate a unique output code specially tracked back to the input only.

QNS 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 function will be used for bitcoin mining and the transaction of data blocks to secure the network

QNS 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).

Hash functions need to be collision resistant as it means that the likelihood of using the two inputs for a same output will not be possible.

#1041

  1. Hash functions are functions where any string can be entered and will convert it to a digital fingerprint (SHA256) to 256 bit.

  2. 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).

Changing a small part of the input for a hash function results in a completely different output. This property is crucial to the ‘proof of work’ algorithm involved in mining: to successfully ‘solve’ a block, miners try to combine all of the inputs with their own in such a way that the resulting hash starts with a certain number of zeroes.
solving the hash for a bitcoin block – which must start with 18 zeros – requires an extremely large amount of computation (and so the combined processing power of all the computers in the network still takes approximately 10 minutes to solve a block).

It’s the need for this large amount of processing power that means new bitcoins get mined over a long period of time, not all at once.

In order to earn bitcoins through mining, you need to put in the huge amount of work necessary to solve a block – and by earning that reward, you’re locking in all of the new transactions into a block, which is added to the permanent record of all previous transactions: the blockchain.

  1. 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 = H, and a ≠ b. Every hash function with more inputs than outputs will necessarily have collisions. [Wikipedia]
#1042

  1. Describe hash functions with your own words
    Hash function is the algorithm that is encripting the input into a fixed 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).
      In Cryptocuresncy Hash Functions represent the current state of the block chain and are used to ensure the ummutability of the process. The transaction information is being encrypted and that creats the hash value. That hash value is the output that is used for identification and confurmation of the transactions into the block chain.

    2. 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 Resistans is preventing the hash funcions from “unmasking” the input. It should be impossible for Hash Functions to have different input with the same output.