Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#3679

  1. a hash algorithm is a universal translator for computers. It is able to receive any form and size of data, including digits, letters or even larger media files, and translates them into an alphanumeric string of a certain size. IN bitcoin the hash function, SHA-256 is used to run its consensus mechanism

  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. a hash function is collision resistant if it is hard to find two inputs that hash to the same output

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#3680
  1. Hash functions are one way input that produces an output. The output is the fingerprint of the input.
    2.Hash function is part of block hashing algorithm. Used to write new transactions into the blockchain. Bitcoin miners use this proof of work as their mining core to solve the block.
  2. This is about difficulty (meaning costly and time consuming) during mining process.
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#3681

  1. Describe hash functions with your own words: It’s a unique digital fingerprint made up of numbers and letters.

  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).It takes the message you want to hash (encrypt), mixes it all up in a blender, and spits it out in an un-hackable, safe address.

  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). You don’t want to ever have two inputs that hash the same output.Two inputs should never collide together in this way, otherwise they would no longer be safe and secure.

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#3682
  1. Its a way to encrypt a transaction by giving an input and getting an output: the hash (encrypted transaction), theres no way you can go reverse and try to get the input from the output.
  2. It hides the transaction in the blockchain and give them a hash, in mining the computers are calculating. the hashes for transactions and being more difficult to solve as there are more bitcoins in the market.
  3. To distribute all the hashes so theres less chance that two different inputs results in the same hash.
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#3683

Collision occurs when two inputs to a hash function result in the same output. A hash function is collision resistant if its hard to find two inputs that would result in the same output. :slight_smile:

#3684

  1. Describe hash functions with your own words
    Hash functions create a one way digital fingerprint for the given input.

  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 crypto hash functions are used to secure the network and its users.

  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 always create an unique output for a given input.

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#3685
  1. hash functions take an input which can be understandable text and converts it into text that is not understandable and of fixed length. hash functions are “one way,” meaning that you cannot convert the hashed text back into the original input text.
  2. In bitcoin, sha256 hash encyption is used to enable transactions to be verified and recorded anonymously
  3. hash functions need to be collision resistant meaning that that no two input hashes should convert to the same output hash. in fact, subtle differences in inputs typically result in dramatically different outputs making it easy to determine if a change was made to the input value after the fact.
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#3686

  1. Hash functions are special functions that when you insert data into them you get a unique fingerprint for that data. Even a small change to the data input such as a space, comma or extra number or letter will result in a completely different fingerprint being generated.

  2. Cryptographic hash functions are widely used in cryptocurrencies to pass transaction information anonymously. For example bitcoin, the original and largest cryptocurrency uses the SHA-256 cryptographic hash function in its algorithm.

  3. Hash functions need to be collision resistant because if a hash function is not then an adversary can break the function with little effort. Collision resistance is the property of a hash function that is computationally infeasible to find two colliding inputs. Cryptographic hash functions are usually designed to be collision resistant.

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#3687

Question #1: Describe hash functions with your own words

Hash functions are equations that for each unique input results in a unique output. Used in cryptographic functions causing a one-way hash for data. Outputs should not be able to be reversed to find the input.

Question #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 in Bitcoin are used to write new transactions into the blockchain via mining PoW efforts. The inputs for the hash functions are new transactions yet to be confirmed. The miners run hashing algorithms until a block is created and permanently written into the Bitcoin blockchain.

Question #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 is the difficulty of having two inputs that result in the same output. It is important that hash functions be collision resistant to avoid a fork in the blockchain. This split in the database where a block is solved by two different miners will have to be resolved with consensus to set the public ledger with the correct data moving forward.

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#3688
  1. The term “hash function” is derived from the French word “hacher” which means to “chop into small pieces”. So a hash function is designed to chop the data. Hash function takes input/message of arbitrary length and does some mathematical calculations and produces hash/digest of fixed length. Output has some characteristics here, it hides the information of input/message. The output is random where input can’t be guessed.
    Hash functions used in cryptography has to be computationally efficient, it should produce hash relatively fast.
  2. Hash functions are used in bitcoin protocols, they constitute the backbone of the proof of work process for validating the addition of new block.
    3.Collision resistance is the property of the hash function which means no two messages passed to the hash function produce the same digest/hash value.
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#3689
  1. a cryptografic algo which converts a string of characters into another string. The resulting string is always unique belonging to the input string and of a fixed length as defined per the used algo - independently of the size of the input string. The input string can not be calculated back from the output string.
  2. hash functions are the basis for the proof of work process and ensure protection against manipulation o f the blockchain and the stored transactions
  3. it is almost impossible that an output string is produced of more than one input string
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#3690
  1. Hash functions are complex ways of coding certain information. It is a sort of universal translator for computers.
  2. SHA-256 is the hash function used for bitcoin. It is used to solve complex mathematical algorithms with computers and software. An input is used with the SHA-256 algorithm to produce an output in bitcoin.
  3. A hash function is said to be a collision resistant hash function if it is a collision resistant one-way hash function.
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#3691

  1. Hash functions or output determined algorithms are essential in Bitcoin security for both authentication and mining functions in the transactional ecosystem.

  2. hash functions can increase or decrease mining difficulty in order to regulate rewards based on the number of miners engaged in maintaining the bitcoin net. The security of SHA256 is used to authenticate individual transactions among several authenticating miners and serve as both PoW and allow the transactional nature of the network to function as intended.

  3. The fact that SHA256 hash’s are collision resistant means that very few inputs can result in the same algorithmic outputs or “hash”.

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#3692

1: Hash functions take an Input of any length and turns it into an alphanumeric fingerprint of a specific length. The input is thereby represented by the output hash, any change to the input will be recognized as the output has would be different.

2: Each Block in the Chain contains a Hash pointer that points to the previous block and contains all its hash. This way all blocks are linked and any change would result in the whole chain having different hash which in a consensus based decentralized environment is not possible.

3: Collision resistant hash functions will not produce the same hash from two different inputs.

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#3693

  1. Hash functions are functions that produce a unique output for a unique input. The output is like a fingerprint for the input. If you change a single bit in the input file, the generated hash will be completely different.

  2. Hash functions are used to add new blocks to the blockchain through the mining process. The inputs for the algorithm are all of the most recent and not-confirmed transactions, timestamp, and reference to the previous block.

  3. In a collision-resistant hash function it is hard to find two inputs that generate the same output. The harder is to reproduce this scenario (two inputs that generate the same output), the more cryptographically secure the hash function is.

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#3694

  1. A hash function generates a unique output for every input . It is unilateral function that prevents reversal discovery of source data.

  2. Hash functions are used in cryptocurrencies to pass transaction information anonymously.

  3. CRHFs are necessary to maintain the trustless environment found in cryptocurrencies.

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#3695
  1. Hash functions are functions that are one way functions. This allows for inputs to be converted to outputs but outputs cannot be converted into their original inputs. This therefore allows for any change in original data to be detected as the original hash will not match the new hash. The hash will be repeated only if the inputs are identical.
  2. Hash functions are used in crypto in order to produce blocks. Miners essentially hash all data along with their arbitrary data in order to create the correct hash i which confirms the transaction. Take a lot of trail and error, hence the need for powerful mining hardware.
  3. Hash functions that are collision resistant indicates that within those hash functions it is nearly impossible to create the same outputs with different inputs.
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#3696
  1. Describe hash functions with your own words. Hash functions are equations that will produce a unique output to an input. The output is in alphanumeric form. The input cannot be re-aquired.
  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 gets “transferred” using hashes which give it the unique ability to be transferred without going back. One way street, no reversal.
  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). Two different inputs should not (almost ever) equal the same output.
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#3697

  1. Hash Function is a function that has a unique input, process it and generate unique output.

  2. Hash function are used in cryptocurrencies to validate and write a new transaction into the blockchain which serve as a proof of authenticity for that transaction.

  3. Hash function need to be collision resistance; so that it will be difficult to find or guess

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#3698
  1. A hash function takes any string of data and converts it into 256 bits. This process is impossible to reverse and provides a unique identifier for data.
  2. In Bitcoin the Hash function is used to hash transaction data. Also 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 not getting the same hash.
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