Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#3899

  1. Hash functions take specific input (text, numbers or even some media files) and give unique output that is a digital fingerprint of that input. That function can not be reversed.

  2. Hash functions encrypt transaction data.

  3. It means that two different inputs can’t have the same output.

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#3900

  1. Describe hash functions with your own words
    A) Each input has a unique output and can’t be reversed.

  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).
    A) (PoW) functions rewards miners with BTC and the (PoW) function is based on the SHA-256. This same function is used in some altcoins.

  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) To prevent hackers from being able to corrupt the system (like MD5) and keeping the blockchain safe and secure.

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#3901

  1. Hash function is a fingerprint for input symbols or even files.
    Which cannnot be translated backwards.

  2. Hash function is used for security purposes
    The hash of a transaction makes it easy to identify transactions on the blockchain
    It’s 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 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).

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#3902

1. Hash function is basically a coding method to encrypt your input that can not be reversed to see what the original input is. Any slight change to the input will give a totally different hash.

2. Hash functions are an essential part of, not only of the bitcoin protocol but of information security as a whole. 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. A Hash Collision Attack is an attempt to find two input strings of a hash function that produce the same hash result. … If two separate inputs produce the same hash output, it is called a collision .

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#3903

I was wondering about the collision resistance and general hash function.
In theory (to me) computer that uses and create the unique hash function could copy the same protocol to built a virus then could potentially clone each and every function in real time… now it would just the matter of speed which function arrives to the desired and matching output… so if this makes any sense…to me this potentially could be a security issue. obviously there is some logic to SHA256 and real time cloning of these function is possible too- if not- explain me why

#3904

1. Describe hash functions with your own words
Hash functions take a unique input of data and gives a unique output of fixed size, which can only compute unilaterally from input to output and not the other way around.

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 bitcoin mining where transactions are computed through the SHA-256 algorithm and miners attempt to solve a block through trial and error, and thus adding a new block to the blockchain. This is a proof of work function.

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 two different inputs cannot produce the same output. Each unique input has a unique output value.

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#3905

Wow! Your map is of hash functions is absolutely amazing!

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#3906

HASH FUNCTIONS

  1. A hash function is a mathematical process that converts a numerical input value into another compressed numerical value. The input to the hash function has a random length but output always has a fixed length. A cryptographic hash function combines the message-passing capabilities of hash functions with security properties.

  2. Hash functions are used in cryptocurrencies like bitcoin to check the integrity of messages and verify information. Cryptographic hash functions add a level of security to the content being sent and protect the identity of the recipient and sender. Hash functions provide anonymity.

  3. Collision resistant means that no two input hashes should map to the same output hash. IOTA is an example of a digital cryptocurrency that had collision vulnerability (Source: MIT Digital Currency Initiative via Investopedia)

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#3907

  1. Describe hash functions with your own words
    Hash functions are unidirectional functions where there is an input that produces an output; one slight change in the input will produce a complete 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). When a btc is transacted; a new hash is added to a block and the block to the chain

  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).
    That it is diffifult or impossible to find two inputs for an output.

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#3908

Describe hash functions with your own words
hash functions are able to produce unique output from user input which is secure due to its one way function.

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 transaction data in order to allow it to be secure and added to the blockchain, a way to verify transactions via mining the hash has to be solved.

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 it is computationally near imposible to find two inputs that will create the same output. This is important because the input refers to monetary values and in-order to create a trustless environment this needs to be as air tight as possible and each transaction needs to enure it has its own unique hash in order for the system to function properly.

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#3909

1- Hash is the output of a computer equation that translates any data input into an alphanumeric output and it cannot be reversed, i.e. it is a one way equation.
2- Any change in input data will modify the resulting hash, thus making transactions fraud proof. Also, since Also, it also serves to reward the miners who solve the hash algorithm.
3- Hash collision is when two different inputs have the same output. Hash collision resistance means that this probability is very hard to happen.

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#3910

[quote=“ivan, post:1, topic:8430”]
Describe hash functions with your own words
[/quote] A function which for each possible input, produces a unique output which can’t be reversed unless brute force is used which is typically too difficult

Hash functions are used by miners who try to calculate what the input should be in order to arrive at the right hash output. If they get the correct answer, they get to generate the next block and are rewarded with Bitcoin.

Collison resistant means that it should be very rare or almost impossible for two hash function inputs to produce the same output.

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#3911
  1. Describe hash functions with your own words

A highly secure way to transfer data where an input has only one output and what is used predominantly on the blockchain.

  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 transactions on the blockchain as a way of keeping transactions secure and giving a way for miners to verify 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).

It means that there should be no way for 2 separate inputs to produce the same output.

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#3912

I’ve got no idea how would you make a virus out of a function. Its just an algorithm :sweat_smile:

#3913

  1. Describe hash functions with your own words
    a hash function is a function that works with an input and returns an unique output known as hash.

  2. How are hash functions used in cryptocurrencies like bitcoin?
    Hash functions is used for in the process of writing new transactions into the blockchain. By having multiple input including data from previous block, timestamp etc, it is near impossible to alter any data in the Bitcoin blockchain without affecting previous data all the way to the genesis block.

  3. What does it mean when we say that hash functions need to be collision resistant?
    Collision resistant is an event in which 2 unique output leads to the same output. It can happened for hash functions but the possibility and timeframe for it to occur simultaneously is infeasible

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#3914

  1. Describe hash functions with your own words
    Complex mathematical process that turns unique data input to unique output.

  2. How are hash functions used in cryptocurrencies like bitcoin?
    Transactions are encrypted with hash functions. Also they prevent creating new bitcoin outside of mining.

  3. What does it mean when we say that hash functions need to be collision resistant?
    That you can’t get the same output via hashing function with different inputs.

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#3915

  1. A hash function is a one way function, which means that you can go from input to output but not the other way around. And every function creates an unique input and output (digital fingerprint).

  2. The inputs in the hash functions are the transactions that haven’t been confirmed yet. When it’s calculated in the function it adds a new block.

  3. It means that it’s hard to find 2 inputs that make the same output.

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#3916
  1. Describe hash functions with your own words
    A hash function is a uni-directional function, which takes an input and produces 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).
    For every transaction that takes place on the blockchain for that currency, the information regarding the transaction, plus the hash of the previous transaction, are hashed. This ensures that the chain of transactions cannot be altered later.
  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 of a hash function means that it is computationally infeasible for two inputs to create the same hash.
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#3917

  1. Describe hash functions with your own words - Each unique input which gives you a unique output with a digital fingerprint

  2. How are hash functions used in cryptocurrencies like bitcoin? 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. 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; that is, two inputs a and b such that H ( a ) = H ( b ).

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#3918

  1. Describe hash functions with your own words
    A hash function is an alpha numeric equation which when given a unique input it producers a unique output. A hash function is a one way function ie you can not use the output of a function to find the input of a function.

  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 like bitcoin because of their unique features and characteristics which make the blockchain trustless and 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).
    The term collision resistant hash means that the hash output of a function is unique to a specific input and can not be the same as another output derived from another specific input.

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