Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#4059
  1. Describe hash functions with your own words:

Hash functions are functions that produce a unique ‘fingerprint’ or output that is based on unique input. It is repeatable, but if any character in the input is modified at all, it will produce a new, totally different unique 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).

Hash functions are used in bitcoin to validate the existence of bitcoin, as well as all the transactions in the blockchain. Miners use them to validate transactions and create new blocks, whilst they try to earn bitcoins.

  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).

Hash functions need to be collision resistant by ensuring that no two inputs produce the same output. Failure to do this can cause double-spending of bitcoin and leave the blockchain vulnerable. There’s also pre-image and second pre-image resistance, two other security issues derived by the ability to determine inputs from a weak hash algorithm.

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#4060

  1. Hash functions are mathematical functions that create a unique output for a given input that can be replicated every time that same input is given, but will be completely different if anything about that input is different. They are also one-directional and can not be reverse engineered from the output.

  2. Hash functions are used in the block minting process and in creating public and private keys for addresses.

  3. Collision resistant means it is statistically improbable to have two inputs create the same output of a hash function.

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#4061

  1. A cryptographic hash is basically a digest or digital fingerprint of a certain amount of data in which each unique input will produce a unique output. Each keystroke generates a new cryptographic hash equivalent, a SHA256 Hash of the input text.

  2. On the block hash the four leading 0000s describe when a block is valid or not. This method will take in a Block from the Blockchain and hash that block into some fixed length string.

    1. The collision resistance property indicates you can’t find any two inputs to map to the same output. It must be a one-way hash function.
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#4062
  1. A hash function is a one-way function that takes any string of data as input, and outputs a string of a set, unchanging size. Computation of the hash is not difficult, but to reverse the operation is completely infeasible.
  2. Hash functions are used in Bitcoin mining, as well as other functions such as block signatures and generation of public keys.
  3. Collision resistant means that it will be computationally infeasible, and therefore extremely unlikely, to find two different sets of input that result in the same output.
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#4063

  1. Hash functions create a unique alphanumeric output of a set length for a given input of any size using a mathematical function and are unidirectional, meaning the input cannot be derived from the output.

  2. Hash Functions are used to create hash values, which in bitcoin are an integral part of the mining of blocks, which allow for the verification and confirmation of transactions into the blockchain.
    Hash Functions are

  • Deterministic
  • Collision Resistant
  • Pre-image Resistant
  • Efficient
  • Impossible to Reverse Engineer
  1. Given that outputs in a hash function are of a set length there are a finite number of outputs that a hash function can produce. Inputs can be of any length, thus the number of inputs that can be computed by a hash function is infinite. With infinite possible inputs and finite outputs, it is a mathematical certainty that more than one input can create the same output, this is a collision. The aim of a cryptographic hash function is to make the likelihood of two different inputs result in the same output so improbable that it reduces the risk to nil, such a cryptographic has can be called collision-resistant.
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#4064

  1. Describe hash functions with your own words
    A hash function converts input data into a unique output data code called a hash. Changing one or more data bits at the input of the hash function and the output hash data output will be different. Feed the same original data input into the same hash function and it will produce the same hash code output.

  2. How are hash functions used in cryptocurrencies like bitcoin? Hash functions are used by mining nodes to confirm a transactions is valid.

  3. What does it mean when we say that hash functions need to be collision resistant? Two different inupts shouldn’t be able to produce the same output hash.

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#4065

  1. A has function is a mathematical process of to go from an input to an output but is only one way so it can’t be reversed from output to input.

  2. Hash functions are used in crytocurrencies for proof of work, mining. It is used for the consensus mechanism. To keep it secure and controlled.

  3. Collision resistance refers to more than one output being the same for multiple inputs. Therefore once you have one output for a certain input, if you found the same output for a different input you could substitute one input for another.

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#4066

1 Hash functions are functions that when you give an unique input you get an unique out. Ie when you you out the input in you will get a output like a finger print. This can not be reversed or anything.
2. Hash functions in Bitcoins are using in mining for new transactions on the blockchain. The inputs for the hash function are the unconfirmed transactions plus additional data related to time and the previous transaction. To solve the block miners try to combine all of the inputs along with data of their own so the outputs start with a bunch of 0’s. It takes a lot of computing power and guessing
3.Collision resistance means that is very difficult to find 2 inputs that produce the same output in a hash function. This is an important property in cryptographic hash functions.

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#4067

Homework - Hash Functions
Functions, Hash Functions, Cryptography

Describe hash functions with your own words

Hash functions have a unique input in which with a mathamathical equation will give you a unique output, its also a one way system, Also If for example you have two hash input which are very similer in digits, then the output of those hash funtions would still have the same fixed length but would not be similer in digits in fact the outputs would have completely different digits, even if only one digit is changed in 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 in cryptocurrencies are used as the building blocks in many applications. Hash funtions are commonly used as digital signitures in cryptographic applications in fact without hash functions bitcoin wouldnt exist. Hash functions are also what makes bitcoin secure. Hash funtions also protect against copying and forgery.

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 collision is when two or more inputs that are distinct from each other produce the same output. The Md5 algorithm has had this issue in the past which makes it vonerable. Hash function in cryptography are preferred to be collision resistant for integrity and security.

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#4068

Describe hash functions with your own words:
A hash function is a function that can be used to map data of arbitrary size to fixed-size values.

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 part of the block hashing algorithm which is used to write new transactions into the blockchain through the bitcoin mining process

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 in cryptography means that for 2 different inputs into a function, the output has to be different and hard to have the same output.
In crypto currency this is important because the hash function outputs has to be unique to prevent tempering of the record

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#4069

  1. Describe hash functions with your own words
    A unique function where the input produces a digital fingerprint

  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 encrypt the transaction data so it is secure

  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 means: given two different inputs A and B where H (A) and H (B) are their respective hashes, it is infeasible for H (A) to be equal to H (B).

For cryptocurrencies, hash functions have to follow this property. Otherwise the output can’t be unique*

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#4070

  1. A hash function is a one-way function that produces a unique output based on the input, giving it a unique digital fingerprint.

  2. Hash functions are used to write new transactions into the blockchain by solving unconfirmed transactions.

  3. Collision resistant means that there is a very small likelihood 2 different inputs will hash out the same output. This is important because this makes it less vulnerable to malicious activity.

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#4071
  1. Hash functions take data and transform it into an output that are difficult to reverse back to the input
  2. Hash functions are used in cryptocurrencies like bitcoin to secure data on the blockchain
  3. Hash functions needing to be collision resistant means that one input cannot produce the same output as another input.
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#4072

Describe hash functions with your own words
Hash functions are one-way functions that create unique outputs that can’t be matched with the input. These outputs are often called digital fingerprints. It would take centuries to match the hashes if someone were to brute-force.

How are hash functions used in cryptocurrencies like bitcoin?
Hash functions are used to verify the transactions and the miners are rewarded with Bitcoin for every block completed.

What does it mean when we say that hash functions need to be collision resistant?
Collision Resistant means that it should be hard/impossible to find 2 inputs that hash the same output.

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#4073

  1. Describe hash functions with your own words
    Hash functions give an unique output for every input, such that the input cannot be known from the output alone.

  2. How are hash functions used in cryptocurrencies like bitcoin? for digital signatures and for creating blocks.

  3. What does it mean when we say that hash functions need to be collision resistant? Hard to find two inputs that give the same output.

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#4074

  1. Hash functions decipher digital data into another digital output - a string of numbers and letters for the observer. The underlying process is that there is a predetermined algorithm how each input particle is transformed into the hash with different levels of complexity for different hash functions. The benefits and characteristics of hash functions are: security, because the functions and output is not reversible back to obtain the input. Another common characteristic is that no matter what type and size the input data is, the output hash will have the same fixed size (within a hash function but can differ among various hash functions). And finally- the output hash result cannot repeat - it has way too many options therefore different inputs cannot somehow end up having the same hashed output. Also even similar inputs will have very different and completely unrelated hashed outputs.

  2. Hash functions are used in cryptocurrencies for security and data integrity reasons. The characteristics of hash functions mentioned in question 1. ensure that cryptocurrencies transactions data is deciphered in a standartized algorithm where it is impossible to find out the data origins from the output and any attempt to manipulate the data in the blockchain would be noticed because any small change to input changes the hashed output completely. The standartization aspect helps with efficiency - meaning that each transaction is not stored in a different format or size, which is hard to compare and verify.

  3. Collision resistant means that two different inputs cannot have the same output hash, i.e. the range of alternatives for has outcomes is so large that they cannot repeat themselves. It is an important characteristic of a hash function because it ensures data integrity - no two transactions can accidentally be mixed up, they are truly unique.

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#4075

  1. A way to secure & confirm a transaction irreversible.

  2. Mathematical process that takes input data of any size, performs an operation on it, and returns output data of a fixed size.

  3. It is virtually impossible to have Output vs input, there is only the contrary Input vs Output who is possible.

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#4076
  1. Hash functions are a way to convert input to output in a unilateral way. Basically, outputs cannot be reverse engineered to determine the original input.
  2. Hash functions perform as data security to ensure data inputs cannot be determined from outputs. These functions create the exact same output if provided the exact same input.
  3. Hash functions must be collision resistant to ensure different inputs do not produce the same output.
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#4077

  1. Describe hash functions with your own words
    Hash functions are functions that can only be solved linearly (in one direction) that give a unique 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). Transactions of any length are uploaded into the blockchain and verified. During this process the information is ran through the hashing algorithm and a unique, fixed length output is given.

  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 resistance in hash functions means it is very difficult to find 2 different inputs that hash out to the same output.

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#4078

Describe hash functions with your own words

  • one way, non reversible

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).
-by confirming the transaction which recorded in a ledger

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).
-no two inputs that result in the same output in a hash function

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