Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#3779

Hash functions are unique inputs that generates a unique output. Changing the input in the slightest way will result in a total different output.

It’s used during mining, it is part of the block hashing algorithm.

Meaning that you can’t have two of the same input giving the same output, and that hash functions are one way - you can’t figure out the input via the output.

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#3780

  1. Hash function is a type of function where 2 conditions must be met: a unique input results in a unique output and it’s a one way function (i.e. you can only go from input to output and not the other way around)

  2. Miners have to hash the blocks header in order to get it equal or below the agreed target. Using SHA-256 function the hash will vary between 0 and 256 bits.

  3. Collision resistant is the characteristic of being super difficult to find 2 inputs leading to the same output

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#3781

A hash function gives any string of data unique 256 bit identifier, its impossible to guess the 256 bit sequence.

In Bitcoin the Hash function is used to hash transaction the data

Collision resistant means that it is very unlikely to get the same hash number

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#3782
  1. A mathematical function taking any form of data or any size (numbers, alphabets, media files) and produce an alphanumeric string creating a fixed length output as a unique identifier for the specific input.
  2. Blocks contain hashes of previous blocks that miners use to solve for the target.**
  3. So that two inputs will have exceedingly low probability of producing the same output.**
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#3783

  1. It is a unique fingerprint that results from a single input.

  2. They are used to link one block to the next block. Block 2 contains the hash of block 1 and so on throughout the chain. In addition, each hash represents the hash of all the information contained in each block.

  3. basically means that different inputs can generate the same ouput, this is not possible in this case.

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#3784
  1. hash functions convert unique input data into a string of numbers and letters that are unique and cannot be reversed.
  2. hash functions convert terms of any transaction into an immutable string of number and letters that cannot be reversed to find the nature of the input
    3 Collision proof means that two different inputs can never product the same hash output
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#3785

  1. A hash function performs a series of transformations on a given input. The output will always be the same for a specific input.

  2. Seed phrases are hashed to provide a unique private address for your wallet.

  3. Collision resistance refers to the need for a hash to avoid giving the same output for two differing inputs.

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#3786

  1. Cryptographic hash functions are used in information security practices such as digital signatures, message authentication codes and other forms of authentication.

  • The same message always results in the same hash value, meaning that the function is deterministic.

  • The hash value is calculated quickly

  • It is impossible to have to messages with the same hash value. (known as a collision).

  • It is impossible to intentionally create a message that gives a given hash value. The slightest change or a few changes to the message should change the resulting hash value to a large extent, so that it seems uncorrelated with the original hash code.

  1. The purpose of a hash is to create a secure data or to protect the integrity of the data. Collision resistance means that it must be impossible to find two colliding inputs.
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#3787

Hash functions is way to encrypt data and preserve its integrity while creating a digital fingerprint!

Bitcoin uses hash functions on a ledger with SHA-256 to obtain mathematically traceability and guarantee the security of the ledger with unbreakable cryptography.

Collision resistant hash functions means that 2 hash inputs does not have the same output!

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#3788

Hash functions are not used to derive public keys, for that the Elliptic curve function is used. :slight_smile:

#3789

  1. Hash functions take input data and irreversibly translate it into a output string, called a hash.

  2. Hash functions are used as part of the proof of work protocol in Bitcoin mining.

  3. A hash function is considered collision resistant if it is hard to find the same output for two different inputs.

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#3790
  1. Hash functions are equations that create secure, unidirectional algorithms
  2. Hash functions are applied to an input to create a string of a fixed length.
  3. Collision resistant means that the values returned in the output of the hash are highly unlikely to be the same
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#3791

  1. Hash Functions are unique, unidirectional inputs

  2. Hash Functions are used for deriving encrypted info (blocks, private keys, etc)

  3. Collision resistance is a property of a hash function that makes it computationally arduous to find two of the same inputs for one output.

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#3792

1: A hash function takes an input and outputs a specific fingerprint that cannot be reverse engineered

2: They are used in cryptocurrencies as a way to ensure the security and strength of the coin so that only the person intended receives

3: Hash functions are made to be difficult to find 2 inputs that give the same output, making them much stronger

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#3793

Functions, Hash Functions, Cryptography

  1. Describe hash functions with your own words
    • Hash functions is a way that you can create a unique, one and only output from an input. Once the input is created, you cannot change it or else it will give you a 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).
    • Bitcoin uses hash functions to write new transactions into 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).
    • It is important for hash functions to be collision resistant because that way you can be positive that you will not have two of the same inputs that will hash out to the same output. This would be important for many different scenarios such as important documents, like legal or medical, that are not meant to be altered. Or, as in the case of Bitcoin, you would not want someone to have another input that would hash out to the same output because then your resulting output could be compromised.

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#3794

  1. Hash functions are functions which take both numbers and letters and converts them into a unique output.

  2. Hash functions are used in cryptocurrency to record transactions.

  3. Hard to find 2 inputs that hash to the same output

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#3795

  • Describe hash functions with your own words
    Hash functions are hash algorithms with a cryptographically unique hash result.

  • 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 in bitcoin protocol are part of the block hashing algorithm . Through mining it writes new transactions into the blockchain.

  • 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 hash function is collision resistant when it is hardcore find 2 inputs that lead to the same output.
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#3796

  1. Hash functions are cryptographic functions that generate a unique output for every unique input. One single change in the text of the input will generate a completely different output. The input can be translated into the output, but the output cannot be translated into the input.

  2. Hash functions are used in cryptocurrency as a backbone to the system. It provides security of assets and value by encrypting the original data and providing a fingerprint to publicly store and verify transaction data. This protects ownership of data and prevents double spending or other fraudulent transactions.

  3. The need for hash functions to be collision resistant means that no two inputs should create the same output. Each unique input requires its own unique output.

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#3797

  1. Hash function is when you produce a unique input and then you get a unique output, and after you’ve done that, there is no going back to the input as its irreversible.

  2. In the protocol of bitcoin hash functions are part of block
    hashing algorithm and its used to do transactions
    into blockchain through mining process.

3.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; that is, two inputs a and b such that H ( a) = H ( b ). Every hash function with more inputs than outputs will necessarily have collisions.

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#3798
  1. Hash function takes array of bytes do magic and returns you array of byte with fixed length and there is no possible way to get input array if you have only output. Also for concrete input you will receive always the same output. As we can call it one way function
  2. It is blockchain clue. Every block contains previous block’s hash. And important thing that block hash equals SHA256(all block data + previous block hash). So it is append only structure. If you want to edit middle part of block chain, you will have to edit half of blockchain because of hash-functions clue
  3. In general set of inputs is much more than set outputs for hash functions. That means some different inputs may had the same hash. And collision-resistance is a property of a hash-function that means it is very hard to find two different array of bytes which be converted in to the same hash.
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