Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#5241
  1. Describe hash functions with your own words - A way to go from a unique input to a unique output that cannot be deduced from the 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).

The private key represents a hash to the public key (crypto address). Transactions linked together are hash of each other unique input with unique output (hash attached to it).

  1. What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best).

Means that it is hard to find to inputs that create same output.

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#5242
  1. Hash function it is a process of making a unique fingerprint from some data input, which can not be reversed.
  2. Hash function in Bitcoin network allows it to be pow blockchain. Where computers compete with each other to ā€œmineā€ (add) next block to Bitcoin blockchain.
  3. Collision resistant means that hash result for different inputs will be also different.
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#5243

Homework on Hash Functions - Questions

  • Describe hash functions with your own words

    • Hash functions are a one way function that gives a specific digital footprint to a specific 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).

    • Generating public keys and block hashing

  • What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best).

    • Collision Resistance - for two distinct inputs, the output of the hash function should not be the same.
      • Example: X1 output should not be equal to X2 output
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#5244
  1. A hash function takes data then converts it into an algorithm that produces a unique input to a unique output `always a one way function.
  2. they get used for mining, and bitcoin purchases, deposits, and withdrawals
    3.it means noone should be able to get 2 different input values that result in the same hash .
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#5245

  1. Hash functions are irreversible and serve as a universal translator for an input to a unique output.

  2. Bitcoin uses the SHA-256 hash function in its proof-of-work process. Proof-of-work is considered the original cryptocurrency consensus mechanism. SHA-256 is highly secure and gives the blockchain encryption to sensitive date that would otherwise be compromised.

  3. Collision resistant means that itā€™s not necessarily impossible, but highly unlikely for the occurrence of 2 unique messages or data set and produce the same hash. The importance of this is that I believe it would be nearly impossible for ownership to be questioned by another user with the same hash output of said asset.

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#5246

  1. A hash function is a unique digital fingerprint assigned to an input of data.

  2. Hash functions are used in Bitcoin for generating public keys and hashing the blocks being mined.

  3. When we want hash functions to be collision-resistant, we are essentially saying that we donā€™t want any two inputs to return the same output.

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#5247

hash functions is a one way function only you can input to receive an output but you cant output to recieve an input. it is the result of a hash algorithm

hash functions are used in bitcoin to convert data to bytes i.e sha 256. if you change just one simple value the output will be different.

collision resitant is it is hard to find two inputs that hash to the same amount

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#5248
  1. Describe hash functions with your own words

A hash function is a mathematical function that converts a numerical input (of any length) into another compressed numerical output (of a fixed lenght).

  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).

They are used to generate keys. Since they are one way, they can not be calculated back from output to input, so you need to have the exact hash to solve a function and gain access to the keys.

  1. What does it mean when we say that hash functions need to be collision resistant? (We didnā€™t use the term ā€œcollision resistantā€ in the lecture, but you will easily find this on Google, we add this question intentionally to make you research information on your own, thatā€™s how you learn best).

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 ā‰  b but H ( a ) = H ( b ).

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#5249

1It converts input in one direction.
2They generate digital signatures.
3No two inputs should create the same output.

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#5250

  1. A hash function is a computation that lets you get an output from an input but is too complex to go from an output to an input.

  2. Hash functions are used mainly for generating public keys from private keys and block hashing from Bitcoin mining and the blockchain.

  3. It means that two inputs cannot produce the same output.

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#5251
  1. Describe hash functions with your own words

A hash function is a fool-proof mathematical function that is able to convert numerical inputs (text, numbers, spaces, etc.) into outputs and not the other way around.

  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 in cryptocurrencies like bitcoin are sha-256 encryptions used to conduct transactions with anonymity.

  1. What does it mean when we say that hash functions need to be collision resistant?
    no two different inputs return the same output
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#5252

1 - A hash function can take something as input and encrypt the output into a line of hexadecimal string based on the base16 system. This cannot be reversed in the current SHA-256 used in Bitcoin.

2 - To try and find a hash beginning with at least 18 zeros

3 - It means that for two distinct inputs, the output of the hash function should not be the same. So for 2 distinct inputs X1 and X2, Hash(X1) should not be equal to Hash(X2)

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#5253

  1. Hash function converts an input and produces a numerical output or a digital fingerprint.

  2. They are mainly used for generating public keys and block hashing. 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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#5254

1. A hash function is a mathematical function that applies on an input and transform it into a result (= output) that is as hard as possible (ideally impossible) to revert.
2. Found a full mathematical explanation.
3. It means that it is hard enough to find two inputs that give the same output. If we find this too easily then the hash function isnā€™t collision resistant.

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#5255

1 - Hash functions convert the data in a only way that cant revert flow example :

Text => binary => function hash ( sha256 example ) => result of hash ( illegible data )

2 - Is used to identify address, transactions and blocks, is used like unique id that is cant be repeated

3 - Is a way to describe a possible collision when someone create a new hash and this is the same of another that really exist this is based in differents text before hashed, i think all the hash has this probability but the probability of this happens may be is a 0.000000000000000001% ( example )

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#5256
  1. Hash functions are functions that receives different sizes of data and converts them to alphanumeric strings.
    It is a one-way function.

2.Hash functions are used in cryptocurrency when mining. In mining, you have to calculate and hash out a result between 0 and 256 before a block is formed and the transaction completed.

3.When hash functions are said to be collision resistant, it simple means that there will never be same output for any 2 inputs.

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#5257

  1. A hash functions takes a set data and converts it into 256 bits of numbers which makes it hard to reverse engineer and a unique identifier for your set of data like a fingerprint.

  2. it is used for transactional data. when mining it is used for finding a specific hash combination with data in that block.

  3. it means two different functions not arriving to the same hash

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#5258

  1. Describe hash functions with your own words
    They are functions that take a unique input and produce a unique output. They are one way functions meaning they only flow in one direction, from input to other put. You canā€™t go the other by taking an output and going back to an input. They also serve as being data integrity checks.

  2. How are hash functions used in cryptocurrencies like bitcoin?
    They have several uses. Each block in the blockchain contains hashed data in which the hashed value of the previous block helps to calculate the current hash value. In other words it plays a large part in block creation. Its also used in mining and creation of bitcoin addresses.

  3. What does it mean when we say that hash functions need to be collision resistant?
    It means its very hard to find two inputs that hash the same output.

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#5259

Hash functions are any function that can be used to generate unique hash digest or hash values.

Hash functions are used to generate public keys and block hashing in cryptocurrency, also think of all private keys that is passphrase has unique public keys.

Collision resistance simply means, two different hash functions can not give the same hash value or hash digest.
In other words, each unique input gives a unique out.

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#5260

  1. hash functions are taking inputs and creating unique outputs

  2. hash functions take inputs like, petter paid sally 1btc on December 25th and create unique outputs based on their binary code/representation.

  3. collision resistance means that itā€™s hard to find collisions for the function. because the output space is smaller compared to the input space we could assume that there would be messages that map the same output.

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