Homework on Hash Functions - Questions

[kirstentait]

1. Hash function means taking an input (could be text, numbers - short or long) and putting them through a process which gives you an output - which is a set number of digits/letters. The output is called the digest, or the fingerprint because it represents whatever was the input.
2. Hash functions are used in bitcoin when someone makes a transaction, and that transaction is the input information. It is hashed and the result is a long string of numbers/letters which represent that transaction.
3. If a hash function is collision resistant, it means that it would be exceedingly unlikely to be able to find 2 distinct inputs that gave you the same output. They do exist, because the combination of numbers/letters is finite, but to be able to find them would be almost impossible and very impractical.

[CryptoCamel]

1. It is a one-way function that produces a unique output given a unique input.

2.They are hashed into other hashes creating a merkle root with a final hash which is the transaction ID.

3.It means it should not allow two unique inputs to produce the same output.

[CryptoFi]

1. Hash functions takes an input ie a string of text and creates a cryptographic output using a complex formulae. This is a oneway function i.e it is near impossible to trace the input from the output alone.

2. Bitcoin utilizes proof of work combined with SHA-256 to obtain mathematical traceability and unbreakability.

The process through which this is ensured is called Bitcoin mining that utilizes Bitcoin hashes generated through SHA-256 function at various steps of mining.

3. 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

[Pattylion]

1)hash is a mathematical functions which is created one way to enable security during the process of the message intended for a particular recipient only .
2)bitcoin uses the SHA-256 hash algorithm to generate verifiable random numbers in a way that requires a predictable amount of CPU effort.Generating a SHA-256 hash with a value less the current target solves a block and wins you some coins.
3)Collision resistant is a security notion of cryptographic. A collision of a hash function is a pair of different INPUTS which give the same OUTPUT .

[Sergio_Garay]

1. Describe hash functions with your own words
   Hash functions have an input and an output that is unique for each input. It´s like a fingerprint. You can´t go from the output to the 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).
   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? (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).
   Hush function is collision-resistant if is it hard to find two inputs that hash to the same output.

[Fabrice]

How Bitcoin addresses are created:

Bitcoin Basics - Discussion

Yes, Some kind of double hash of a public key with a prefix and checksum. How to create Bitcoin Address The correct way to create a Bitcoin address is to use well tested, open source, peer reviewed wallet software. Manually handling keys has resulted in funds loss over and over again. Unlike other centralized systems losses in Bitcoin are usually unrecoverable. Here is a brief overview of how address generation works, for informational purposes: 0 - Having a private ECDSA key 18e14a7b6a307f4…

[Roger777]

1. Describe hash functions with your own words
   Hash function means its a one-way streak from input to output.

2. How are hash functions used in cryptocurrencies like bitcoin?
   In Bitcoin, hash function is used to create addresses, private and public keys. Transforming transactions which can be recorded as hashes in a ledger.

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 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 ).

[PapatoniC]

1. Describe hash functions with your own words

• Hash function translates an input into the same output as a result.

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 translates transactions with SHA-256 hash algorithm into outputs. This is secure since its not
     possible to find the source transaction from the function output and efficient , since we always get a
     fixed output no matter how long its the input.

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 means that it is not possible to find the same output for 2 different inputs of the function. So the output of a hash is always unique like a fingerprint.

[mbruno]

1. Hash functions is where you insert an input and generates a unique output like a fingerprint.
   The output will be in a 16 bit base format with letters and numbers using SHA256 .

2. Hash functions in bitcoin are used to write new transactions into blockchain through mining.

3. its means that its needed so makes it harder for the possible attacker to break the function.

[Alko89]

@CryptoCamel

2.They are hashed into other hashes creating a merkle root with a final hash which is the transaction ID.

Transaction id is the transaction hash and a merkle tree is a tree of hashes whose leaves are the txids. The root of the merkle tree is calculated from these txid which is then used in the mining process to generate the block hash.

[Olivier]

1. Hash functions provide a digital finger print (output) to any input entered. To be efficient it can only go from input to output and not the other way.

2. Hash functions are used in the algorithms used to write transaction into the blockchain through mining.

3. It means that it needs to be able to have a different output to every input entered. If we have the same output for 2 different input we have a collision.

[Wanda]

1. A hash function is a function used to encrypt inputs. They are one-sided functions made to make the output of the function unreadable, in order to protect the input from the public.
2. Hash functions are used in cryptocurrencies to protect private keys. the hashed versions are called public keys, its what allows the ledger to be public.
3. When a hash function is collision resistant, it means no 2 inputs will have the same output. This is a very important feature to have in a hashing function.

[Danielito]

1.Each unique input generates a unique output. If only one character is changed, the entire output changes. Importantly, this function is a one-way function. That means you don’t come back from the output to the input.

2.Hash function SHA-256 (Secure Hash Algorithm with 256Bit -> 64 characters) used as proof of work in the Bitcoin mining algorithm, creating addresses like private and public keys

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

[JuanitoPecados]

1/ the hash function is a way to encode data in such a way that its fingerprint is unique and impossible to know the information that it contains, having only the output

2/ It is used to store information in such a way that it is transparent, secure and accessible to all as long as certain conditions are met

3/means that the hash function has the characteristic that it is almost impossible to obtain the same hash from 2 different inputs

[Fosback]

@ivan

• Describe hash functions with your own words

A hashing function encrypts digital information only one way, it is very unlikely for anyone to be able to revert a hashed string to its original state.

@ivan

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).

The hash function is used in the creation of new blocks. The previous blocks hash is combined with the contents of the new block and appended a nonce. If the new hash is lower than the difficulty level it is approved by the network and added to the blockchain.

@ivan

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 possible for the hash to generate the same output for two different inputs. Though extremely rare it can happen. To be collision resistant means that the likelyhood of this to happen is close to impossible.

[Alko89]

@Wanda

Hash functions are used in cryptocurrencies to protect private keys. the hashed versions are called public keys,

@Danielito

creating addresses like private and public keys

Hash functions are not used to derive public keys, for that the elliptic curve is used. However the address is a hash of the public key.

[Lior]

1. Describe hash functions with your own words

Hash function can take any string input and convert it to a unique string with a fix amount of characters depending on the hashing algorithm. the hashing function most perform with 100% consistent results for each 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).

hash function been used all over the cryptocurrencies world from wallet address or seeds, private keys, block indexing and hashing, and for mining algorithms puzzle solving.

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” meaning that there’s no two (or more) inputs that will produce the same output.

[MattL]

1. Hash functions are a way to secure inputs but creating complicated and original outputs that cannot be traced back to what the input was. A key security component of Bitcoin.
2. Hash functions turn inputs into unique and complicated outputs in order to secure data on the blockchain.
3. Collision resistance refers to hash function inputs that never have the same output. The harder it is to duplicate outputs or inputs then the more secure the system.

[mattwmc]

1. A function that creates a unique output from a unique input and is near impossible to crack (relate the output to the input)

2. hash functions are part of the block hashing algorithm which is used to write new transactions into the blockchain through the mining process.

3. Collision resistance is important because it provides security and stop attackers from being able to figure out the input from the output

[jarekpiot]

Homework on Hash Functions - Questions

1. Describe hash functions with your own words
   Bitcoin has funtios are one way computation functions that have unique outputs
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 transaction has its own hash
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 is when an input has an identical hash output, ie its very important in cryptography that this does no occur