Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#4821

  1. hashing your data gives you a unique fingerprint with which you can verify the integrity of your data. when you send your data with the unique hash number, the receiver of the information can check if the data is not tampered with.

  2. hash functions are used to create new blocks on the blockchain, which can be used for transactions, wallets etc.

  3. collision resistant means that the used hash cant produce 2 the same hash outcomes. hence that no document/data/whatever can be verified by another hashcode

1 Like
#4822
  1. One way function because you can know the output based on the input but not the other way round. Each unique input has a unique output.
  2. In bitcoin, the input for a hash function is a new transaction that has not yet been added to the blockchain.
  3. When in a function, no two inputs can have the same output, then the function is said to be collision resistant.
1 Like
#4823

1 - Hash function is a mathematical algorithm that converts any input data to a hash that can be an hexadecimal number. This hash is unique to each data input. If just a single coma or space is changed in the original data, the output hash will be different.

2 - Hash functions are used in the mining process that write new transaction in the blockchain.

3 - It is mathematically possible that two different inputs result in the same hash, called hash collision, however it is important that this possibility is very low creating collision resistance.

1 Like
#4824
  1. Describe hash functions with your own words
    It is a algorithm that converts any input into a unique output that isn’t possible to reverse.
  2. How are hash functions used in cryptocurrencies like bitcoin?
    Bitcoin uses hash functions to run its consensus mechanism.
  3. What does it mean when we say that hash functions need to be collision resistant?
    Collision resistance is a property of cryptographic hash functions. A hash function is collision resistant if it is hard to find two inputs that hash to the same output.
1 Like
#4825

  1. Describe hash functions with your own words
    A hash function provides a digital fingerprint that give it a digital test as an input. It is difficult to extract an input from an output. A hash function used in bitcoin is known as 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).
    I believe hash function as used as part of the mining verification 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).
    This means that no two inputs when hashed provide the same output.

1 Like
#4826
  1. Describe hash functions with your own words
  • In a good metaphor - hash functions are like vegetables that have been put through a blender, where the nutritional meaning still remains but the input is unrecognizable and you can’t put the output back together into its original input.
  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).
  • As input is processed into a finger-print like output, it allows the bitcoin to have uniquely identifiable transactions.
  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).
  • Collision resistance means that two different inputs can not produce the same output.
1 Like
#4827
  1. Hash Functions give Data a unique unbreakable digital code.
  2. Mining Bitcoins, aka, solving the Hash for a Bitcoin Block, as of time of writing, must start with at LEAST 18 ZEROS! This takes the combined processing power of ALL computers on the network to solve… and STILL TAKES ROUGHLY 10 MINUTES.
    It’s a staggering amount of computation power.

It’s this need for such a large supply of processing power that dictates Bitcoin to be mined slowly over along period of time.

In Bitcoin mining the Inputs for the Function, are all the most recent, Not yet to be confirmed transactions, along with additional Inputs which relate to the timestamp and a reference to the previous block.
3.If Hash Function isn’t collision resistant an adversary can break the function with little effort.
You have a set X of possible inputs… for each input x E X the hash function F with output h=F[x] note that there are more than one x that will give the same h as a result, and the set of all possible results of F is finite, unlike x.
The functions role is to make it difficult for the attacker to find any x’ so that F[x’] = F[x’] = h.

1 Like
#4828

  1. It is a complex algorithm which produces a unique output (similar to a fingerprint), which means that even if there is the smallest change in the input the output will be completely different. Additionally, there is no way of inferring what the input is but viewing the output and in this way, the only operate in 1 direction, from input to output.

  2. hash functions act not only to create unique identifiers, but also to challenge the computational power of miners, which are not only affected by levels of difficulty, but also statistically low chances of solving the computational problems set.

  3. It simply means that no two inputs can ever have the same output.

1 Like
#4829

  1. In a hash function each input creates an unique output. Inputs cant get recreated if you know the output (one way function)

  2. In Bitcoin hash functions are used for mining new transactions in the bitcoin blockchain.

  3. Colision resistant means two different things cant get the same output.

1 Like
#4830
  1. Hashing is converting data into a fixed-length of output.
  2. Hashing is used in Bitcoin to store transaction data into hashes.
  3. collision resistance means that two different inputs will never have the same output hash.
1 Like
#4831
  1. Describe hash functions with your own words
  • hash functions are a universal translator that will produce a unique output or digital signature when given an input, and it is regarded as mathematically not possible to reverse the output for the initial input.
  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).
  • Hash functions are used in cryptocurrencies to derives unique private and public keys
  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).
  • two different inputs should not equal the same hash output
1 Like
#4832
  1. Hash Functions is an algorithm that takes a value and computes it into an abitrary size. Specifically for Cyrpto, it uses SHA-256.

For example.
I type (input) “Hello Sir.” then the Hashing happens and you get an ouput = 10211031cc63c0ff6873d89795b7ff2c6c626fb874ce9d5d6161be01a11ffcdf . Which is the SHA-256 Hashing system.

  1. Hash functions are used in mining for new coin on the blockchain. These hashs are inputs until approved by POW then added as output. Hash functions act as the security and “firewall” that prevents attackers from finding your key and taking the bitcoin you posses.

  2. Collision resistance is a hash function that makes it hard to track and pinpoint the inputs to the outputs. An example of a no longer collision resistant hash function is MD5. A hash function that is being used today is SHA-256 which has no collision.

1 Like
#4833

  1. they’re complex, special functions where you insert data, you get an alphanumeric unique fingerprint output that cannot be reversed to find its input.

  2. the transactions are taken as input then put into a hashing algorithm, like sha-265 in bitcoin, then gives out an output

  3. it means that it’s impossible to find an output with 2 inputs, which is a basic rule in mathematical functions.

1 Like
#4834
  1. A function that turns an input into a unique output (digital fingerprint) for that specific input. It should not be reversible and if so it’s no longer a true hash function.
  2. Used to turn transactions into a unique fingerprint so you can follow the transaction.
  3. So two different inputs lead to the same output hash. In other words, a hash function needs to turn all inputs into unique outputs if two inputs have the same output, it is not collision-resistant.
1 Like
#4835

  1. Hash functions are functions with a unique input and a unique output thus creating a unique digital fingerprint.

  2. Hash functions are used to hash transaction data.

  3. It means that it is difficult to find two inputs that provide the same output.

1 Like
#4836

  1. A hash function is a function that maps an unique input to a hash of fixed value.

  2. Hash functions are used for authentication and validation.

  3. A hash fucntion is collision resistant if it is hard to find two different inputs that generate the same output.

1 Like
#4837

  1. A function that a given input will only produce one unique output. Given the output data, it is impossible to retrieve the input data. Numbers and letters (as numbers) can be in the input data and output data.

  2. Hash functions are part of the block hashing algorithm which is used to write new transactions in to the blockchain via the mining process.

  3. A collision resistant hash function is one in which any output can only be produced by a single unique input. Meaning that 2 different inputs can not produce the same output.

1 Like
#4838

  1. A hash function is a mathematical algorithm that produces a unique hash. This output is a digital fingerprint of the input, however you cannot reverse calculate the input using the output.

  2. With cryptocurrencies like bitcoin, the transactions act as the input thats ran through the hashing algorithm, giving you a digital fingerprint (output) of a fixed length. To solve a block miners must combine the input with their own piece of input data, to come up with a hash that has at least 18 zeros. With the combined procession power on the network, it takes about 10 minutes to solve one block. By solving a block, they earn rewards and forever lock away the transaction into a block, joining the blockchain.

  3. Collision resistance means that it is hard to find two inputs that hash to the same output. A hash function with more inputs than outputs will have collisions. Collision resistance doesn’t mean that no collisions exist, they’re just hard to find.

1 Like
#4839

1 Hash functions are that smart functions that will basically get you unique fingerprint for each unique input its one way function

2 . Hash functions used in mining blocks and eventually verify new transactions in bitcoin.

3 Each input is transformed to unique output and probability of two different inputs transforming to same output is infeasible if not impossible.

1 Like
#4840

  1. Describe hash functions with your own words.
    Hash functions are a unique digital fingerprinted alphanumeric code where input data will produce an output. The development of this code can only traverse from input to output making the input highly secure.

  2. How are hash functions used in cryptocurrencies like Bitcoin?
    Hashing is a mathematical function that can take any form of data (alphanumeric) size and produce a fixed-length output unique to that particular input. The input hash function comprises of transaction details along with time stamp and other recent data. Output data length is always fixed to the algorithm’s specifications hash length of 256- bits. The mathematical hash functions vary largely in complexity making it difficult for a hacker to brute force into. This revolutionary technology is enabling decentralised currency and peer to peer transactions highly appealing to the modern day public.

  3. What does it mean when we say that hash functions need to be collision resistant?
    Collision resistance is a property of cryptographic hash functions. A hash function is collision resistant if it is hard to find two inputs that hash to the same outputs. If collisions were possible they would allow an attacker to take authentic messages.

1 Like