Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#4239

  1. Compared to normal mathematical functions, hash functions produce a certain output, which can to be reversed in order to get the input.

  2. Hash functions are part of the hashing algorithm, which is used for writing new transactions into the blockchain through the mining process. It’s the need for this large amount of processing power that means new bitcoins get mined over a long period of time, not all at once.

  3. If it is hard to find two inputs that hash to the same output.

1 Like
#4240

A hash function is a one-way function where you insert an input and get a unique output or fingerprint.

Hash functions are used in cryptocurrencies like bitcoin by hashing or processing and verifying transactions

Collision resistant means two different inputs not giving the same output

1 Like
#4241

  1. Hash functions have two features. One, it gives a unique output for a unique input. Two, it is impossible to find the input of the output.

  2. In bitcoin, hash functions are used in mining (proof of work). When a transaction is requested, miner tries to find the input that gives an output of for example having 30 zeros at the start.

  3. Hash function give a unique output for a unique input. Therefore, two different inputs cannot have the same output.

1 Like
#4242
  1. a Hash function will take any file, text or code and give it a unique fingerprint.
  2. Bitcoin uses hashing algorithm SHA256, the transactions are takes as input and run through the hashing algorithm which will give the output(a hash)
  3. When we say it needs to be collision resistant we mean that when we use two input strings and find the same result as output(get the same hash as output).
1 Like
#4243
  1. Hash Functions converts Data in an ‘Alphanumerical’ algorithm, in other words and encrypted output.
  2. In cryptocurrencies like bitcoin, hash functions are encrypted demands used in Blockchain computations. In other words creating complex mathematical equations in order to add new blocks to the Blockchain.
  3. Hash Functions being ‘Collision Restraint’ means to make it extremely unlikely at two inputs would produce the same output.
1 Like
#4244
  1. Describe hash functions with your own words. - They are one way functions that are based on a hexadecimal representation of the input that cannot be recovered if SHA256 is used.
  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 mining. Miners then are guessing a hash number of input and if the value is less or equal to the output number the next block is added to the blockchain and a miner is awarded some bitcoin.
  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 are collision resistant because every input produces a completely different output even if only one digit is changed in the input. This is a basis for the finality of the blockchain technology.
1 Like
#4245
  1. Describe hash functions with your own words
    Hash functions are functions that are unidirectional meaning an input leads to an output. But the reverse is nearly impossible to deduce.
  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 part of the hashing algorithm used to create new transactions in the blockchain through mining.
  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 need to be collision resistant to ensure security… it should be difficult to guess input values from outputs.
1 Like
#4246
  1. Hash Functions are one way functions which produce a unique Output.
  2. Hash Functions are used to verify a transaction. Blocks are created by successful verification of the hashes.
  3. Collision Resistant means hard to find two inputs that hash the same output.
1 Like
#4247

  1. Describe hash functions with your own words
    Algorithm that produces a unique outcome to a unique 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).
    Each coin or portion of a coin has a unique hash address, this cannot be duplicated.

  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).
    2 Different inputs cannot give the same output, this provides security to the network

1 Like
#4248
  • Describe hash functions with your own words

Hash function is a one way function where one unique input produces an unique output like a digital fingerprint. There is no possible way to go from output to input.

  • How are hash functions used in cryptocurrencies like bitcoin?

The hash function SHA-256 is used in bitcoin to encrypt each block of the ledger.

  • What does it mean when we say that hash functions need to be collision resistant?

Collision resistant in hash functions mean no two inputs can result in the same output.

2 Likes
#4249
  1. Hash functions are way to incript informaion, in a form of digits and letters. The outputs are tottaly unique because output cannot be reversed. Its digital fingerprint.
  2. Hash Functions are used to create secret code for the transactions of Bitcoin and more. They are stored on the blockchain as every new function need to be validated with the previouse. This job is done by the miners and require lots of computing power because they are very complex!
  3. Collision resistant mean that is impossible to have 2 diferent input functions with the same output!
1 Like
#4250

  1. Hash functions like SHA-256 are one way functioning algorithm, taking unique input to obtain a unique hexadecimal output such as base 16, the digital fingerprint of the transaction hashed.

  2. Hash functions are used in cryptocurrencies like BTC to process transactions in a decentralized trustless environment. Using the proof of work protocol to run the SHA-256, miners hash the input over and over to produce the same output. The 16 base hash generated establishes proof of work for the blockchain.

  3. Collision resistant hash functions refers to a situation in which two different inputs hash out to the same output.

1 Like
#4251

A Cryptographic Hash Function is a matematical algorithm in which each input of an arbitrary amount of data is taken to produce its own unique output; in illustration, it is an irreversible one-way function that coverts input data into a 64 digit long hashed address code consisting of 10 numbers [0-9] and lower-case roman letters [a-f], and this output is that data’s “finger print” because they are exceedingly different from each other as two inputs will never have the same outputs.

Hash Functions are utilized in Bitcoin for two purposes:

A) SHA256 is the first hashing function to have ever been utilized by Blockchain technology (Bitcoin) to perform a process called Proof-of-Work; which is a solved cryptographic ‘puzzle’ or in other words a data of evidence that an incentivized miner achieved to solve a complex mathematical problem, which after consensus approval the new block consequently can be added to the chain.

To Illustrate an example: Let’s say there are two miners, who are owners of specialized nodes (i.e. computers used for mining) on the blockchain network; Gilgamesh (G) and Hammurabi (H). G finds a mathematical problem which he can solve to acquire an answer. His answer is then hashed through the SHA256 algorithm system to generate a unique, irreversible, and unmatchable output. Thanks to bitcoin’s transparent nature, H can see the on the ledger that G completed the puzzle, but H does not know how G acquired the result nor can he see the answer. All H can see is a 256-bit fixed-length string, which is a hash. He then only has to compare the G’s hash with the hash he has in order to determine the answer is correct if both hashes are identical.

B) The second function that SHA256 was assigned for in blockchain is the generation of new public addresses; a process in which the public key of a block is converted to a public address. Technically speaking, transactions are taken, and the input of that public key is hashed into a 256-bit fixed-length string, which acts as a public address code.

Before Blockchain, these keys were invented for the purpose of sending private messages on the Internet. In Blockchain however, these keys are used to generate public addresses to transfer funds from one wallet to another. Each block consists of a #, a public key, and a private key. The public key derives from the private key through a process called Elliptical Curve Cryptographic [ECC] multiplication. Since the private key is the creator of its public keys, it therefore can decrypt the encrypted data that it received on its public keys. The public key then gets hashed in to a public address to-which anyone can send encrypted data. Therefore, absolutely nobody, but only the key owner can decrypt and read the messages it received.

Cryptographic hash functions are designed to be collision-resistant, a property of the hash function that prevents the collision of two different inputs producing the same output.
Although they’ve been designed to prevent brute-force to cause collision attacks, unfortunately MD5 and SHA1 ultimately had been broken.

Collisions occur when the same output, H(a) = H(b) , has two different inputs, a =/= b .

So far SHA256 has proven itself to be the most securable and collision-resistant hashing function for cryptocurrencies such as Bitcoin. If we calculate 2^256, we get a chance of 1 in over 115 quattuorvigintillion to find a collision.

1 Like
#4252

1 take any data and transcribe it into a alpha numerical fingerprint of that data
2 hash functions are used to hide the input while still keeping the original information intact
3 no way to get the same output from different inputs

1 Like
#4253

  1. A hash function is a one way function that computes a (hopefully) unique fingerprint in the form of a fixed length bit string (the hash) for it

  2. Firstly, they are used for generating the public bitcoin address from the public key derived from ones private key. Secondly, they are used for the proof-of-work algorithm (miners try to find a hash that starts with a certain amount of zeroes as a proof of work, whoever solves it first can add the block and is rewarded bitcoins for it). Thirdly hashes are used as transaction ids.

  3. “Collision resistant” means that it should be extremely unlikely that the hash function produces the same output for two different inputs.

1 Like
#4254
  1. Describe hash functions with your own words

A Hash function is a one-way cryptographic algorithm that maps an input to an output. It is a one-way function and cannot be reversed.

  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).

It is used as proof of work.

  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).

SHA-256 is collision resistant, meaning that it is hard to find two inputs that hash to the same output, making it hard to duplicate and create forgeries of files.

1 Like
#4255
    • One way mechanism, no reversal of a hash possible
  • Example: fruit mixer, blended fruit impossible to reconstruct
  • The slightest change in a hash, will result in a complete different output
  • PoW = Proof of work function, Bitcoin miners try to generate a new block for the blockchain with computer power and mathematical solutions and get rewarded in bitcoin

In cryptography, collision resistance is a property of cryptographic hash functions : a hash function H is collision - resistant if it is hard to find two inputs that hash to the same output; that is, two inputs a and b where a ≠ b but H(a) = H(b). … ) hash operations on random input is likely to find two matching outputs.

1 Like
#4256

  1. A hash function is a cryptographic computation that takes any input and outputs a unique digital fingerprint of the data.

  2. Bitcoin uses hash functions to encrypt the data of each block, and link them together by including the hash of the previous block in the data that is hashed for each subsequent block.

  3. It means that the hash function used should minimize the possibility of any two different inputs resulting in the same hash. This is important to ensure the security of the network. If two inputs produced the same hash, and a bad actor was able to use them to hack any transactions, it would jeopardize the entire blockchain.

1 Like
#4257
  1. a hash function takes an input and basically gets a digital fingerprint of the input as a result.
  2. Hash functions are used as blocks of hashes which represent unique transactions, so basically the blockchain would be a chain of one digital fingerprint of another digital fingerprint containing more data to add to the chain database.
  3. collision resistant means two different inputs are their respective hashes, it is impossible for the hash of A to be equal to the hash of B
1 Like
#4258
  1. Describe hash functions with your own words

They are one-way functions where each unique input gives a unique output, yet not vice-versa.

  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).

BTC uses a SHA 256 hash that creates a “fingerprint” of each transaction on a block in the chain. A BTC protocol has hash algorithms used to write new transactions in the blockchain through the mining process.

  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).

Cryptographic hash functions are collision resistant so no two inputs will create the same output. In other words, “two inputs (are mapped) to two different values.” Hence, no collision. MD5 and SHA-1 are susceptible.

1 Like