Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#5238

  1. Hash functions take any unique input and give out an encrypted unique output. Another important characteristic of hash functions is that they are one-way functions where you can insert an input to get an output but you can’t reverse-engineer it to pull in an output to get the original input.

  2. Hash functions can be used to secure private keys to people’s wallets and passwords to accounts. Since hash functions produce unique outputs, anyone without the correct password/key won’t be able to access the account; ideally the rightful owner will only have access. In terms of mining, the hash function is useful in verifying transactions before they added to the blockchain. Miners must find the correct nonce to input to produce the desired hash before being awarded BTC; incentivizing people toward honesty rather than attacking the blockchain.

  3. Hash functions need to be collision resistant, meaning that they are unlikely to produce the same output for two different unique inputs. This is important because if there is no resistance, it becomes easier for an attacker to figure out the inputs for a repetitive hash, resulting in undesirable scenarios (e.g. lying that they computed enough times to find the desire hash in mining or faking a digital signature on some contract that the actual party did not agree to).

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#5239
  1. An algorithm for each unique input it will produce it will produce unique output.
  2. They are used to create keys and block hashing.
  3. Collision resistant- If two input are different than there hash function always be diffrent.
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#5240

  1. Describe hash functions with your own words
    hash function take input and put through and outputs to a unique output of sha256

  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 is part of the mining process and the blocks are put through the hash process and checked and then written to the blockchain and way of checking information is correct.

  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 mean that two inputs into a function will not get the same output.

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#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 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).

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 “mine” (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 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 - 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 it’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 don’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 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 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 ).

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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 isn’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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