Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#2893

1 Describe hash functions with your own words
Its a very specific function which will never allow you to define the input trough output, algorithms can only be solved to find the ultimate hash output, they can not be reversed to calculate the initial raw data

  1. How are hash functions used in cryptocurrencies like bitcoin?

Bitcoin’s blockchain uses these important hash algorithm characteristics to run its consensus mechanism. In order to reward miners with Bitcoin, the currency uses the proof-of-work (PoW) function

  1. What does it mean when we say that hash functions need to be collision resistant?
    It means that it is hard to find two inputs that hash to the same output
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#2894 
1. 
• A hash function is a mathematical function that takes a variable input & maps it to a fixed value & each type of hash function has a different level of complexity and difficulty. . Hash functions are commonly used data structures in computing systems for tasks, such as checking the integrity of messages and authenticating information. The hash function of BTC is SH256, where as IOTA uses Curl. Hash functions should make it impossible for the input to be derived from the output, however this is not the case with regards to MD5.
2. 
• Hash functions are used to pass transactional information anonymously in the case of bitcoin, where new transactions are added to the blockchain. 
3. 
• Collision resistance refers to the hash function making it hard to find two inputs that hash to the same output, such as H(a) equalling H(b). Collision resistance does n’t mean that that no collisions  exist, only that they are difficult to find.
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#2895

1 Hash function is the proccess of hashing data (transactions) in a specific algorithm
2 Data in cryptos is hashed by nodes, than they translate and keep this information
3 there is no more outputs than inputs in function

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#2896

  1. Describe hash functions with your own words
    Hash function describes where a specific input gives a unique output dependent upon the hashing function used. It is unidirectional. To work out the input would be to have cracked the hashing function.

  2. How are hash functions used in cryptocurrencies like bitcoin?
    Bitcoin is essentially a digital ledger of hashes that uses proof of work along with SHA-256 to obtain mathematical traceability and unbreakability.

  3. What does it mean when we say that hash functions need to be collision resistant?
    A hash function will be collision resistant if it is hard to find two inputs that give the same output.

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#2897
  1. Describe hash functions with your own words
  • One way functions where inputs create a unique output.
  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).
    Public and private keys are created in order to create a unique output that can not be reversed to find the input.
  2. 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).
    If two outputs are created that are identical, it will be so hard to identify them making it almost nonexistent.
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#2898
  1. Describe hash functions with your own words.

A form of encryption whereby an exact input becomes an unidentifiable string of code (the length and complexity of which is based upon the type of hash function used). The input will always equal the hash (providing it hasn’t changed in any way) but is very nearly impossible to work out what the input was when only given the hashed output.

  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).

Transactions made on the bitcoin network are hashed before being placed into a block. These hashes are then paired to create a new hash which is then paired with another hash until a final hash of hashes exists. Blocks containing the hashed transactions are identified by this final hash (Merkle root) and miners have to find this hash result (and the nonce value) in order to claim the block reward to then have the block added to the chain. The new block will also contain the root hash of the previous block (hence the “chain” in blockchain) and provide a small part of the hash of the subsequent block.

  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).

Collision resistant means no differing inputs should ever be able to produce the same output.

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#2899

Thanks for the information, I’m going keep learning until I understand this crypto.

#2900

  • Describe hash functions with your own words
    Hash functions are algorithms that accept input data and generate a unique alphanumeric string to represent it, it is like a signature representing the input data. Usually the string is 64 bit, 128 bit or 256 bit in length. The algorthims are easy to use to create the same output string for the same input data but are almost impossible to reverse engineer the output string back to the input data.

  • 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 in all the headers of the blocks and the blocks are all in linked lists. Each block in the sequence has the hash from the prior block. Therefore trying to alter any block in the chain changes the subsequent hashes of every block after it.

  • What does it mean when we say that hash functions need to be collision resistant?
    Collision resistance is the (un)likelihood of two inputs producing the same unique hash. Therefore when a two inputs produce the same hash and are collision resistant then it is safe to assume both inputs are the same.

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#2901
  1. one direction function converts the input to unique output, and it can not be reverse
  2. minning problems, generate keys,
  3. different input A & B, H(A) <> H(B)
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#2902

1- Describe hash functions with your own words
A hash function give a result or output, that is unique and can’t be reversed to find the input.
It is a virtual fingerprint.

2-How are hash functions used in cryptocurrencies like bitcoin?
Hash function are used by the miner to add new block to the blockchain by solving complex calculation to find the output.

3-What does it mean when we say that hash functions need to be collision resistant?
It means that given an input, the hash function can’t have two output to be collision resistance.

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#2903

Collision resistance is the possibility of two inputs resulting in the same output because the number of inputs (basically infinite) is bigger than the possible number of outputs (2^256). :slight_smile:

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#2904

Hash functions are not used to derive public keys, for that the elliptic curve function is used. Hashing is used in the block creation process and also transactions are hashed to get the txid. :slight_smile:

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#2905

  1. Describe hash functions with your own words
    Hash functions is an algorithm used to create digital signature of a data

  2. How are hash functions used in cryptocurrencies like bitcoin?
    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?
    collision resistant means it is hard to find two inputs that hash to the same output;

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#2906

Hash functions are digital signatures if they were not collision resistant then it would be easier to break and fake the digital signature and for example submit a different paper as evidence

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#2907

  1. Describe hash functions with your own words
    Hash functions are mathematical algorithms that take input of any length and convert it into
    a fix length unique string of text. The resulting output is called hash value. For the same input the hash value will always be the same. The slightest change to the input will result in a totally different hash value. The resulting hash value cannot be used to determine the original input values. You can only go one-way from input to output. There are many formulas that can be used to generate hash values, for cryptographic we use SHA-256 algorithm.

  2. How are hash functions used in cryptocurrencies like bitcoin?
    Hash functions are used to represent the current state of the bitcoin blockchain.
    Every transaction has certain bits of information like the amount, sending and receiving addresses, and timestamp. These are converted into a unique hash value which becomes the transaction id for that transaction. These transaction id’s can be used to verify a transaction has occurred. The first block in a block chain is called the genesis block and contains all the transactions and when combined create a unique hash of all the transactions inside that block. When a new block is created all the transactions in the new block plus the hash value of the previous block (in this case genesis block) is combined to create a new hash value. Thus as new blocks are added to the block chain the values from every previous block is combined with subsequent blocks to create an immutable chain of transaction information and a transparent network.

  3. What does it mean when we say that hash functions need to be collision resistant?
    Since hash functions can have infinite input length and a predefined limited output length it is inevitable that two separate inputs may produce the same output hash value. If two separate inputs produce the same hash output it is called a collision and the hash function we need to use must be resistant (not allow) this to occur. Hence be collision resistant is the cryptographic property of hash functions to not produce the same hash value for different input values.

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#2908

Don Michelin - Questions

  1. Hash functions are functions used to take an input of data down to the binary code, then translate it to a hexadecimal output, and that becomes the unique fingerprint of the input. You must also never be able to use the output to find the input. If that happens like it did with MD5 it becomes broken/useless. Also any change in the inputs binary code must result in a new output hash.

  2. The hashes are used in Bitcoins Proof of Work mechanism. Miners work hard to solve the target hash to complete the block.

  3. Collision Resistance means that two or more inputs do not share the same output hash. If two or more inputs share the same output hash then there is a collision.

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#2909
  1. Hash functions are a unique input/output algorithm used to send data on the blockchain, these algorithm use cryptography to secure data.
  2. hash functions are used to transfer cryptocurrencies to an address or individual by means of computation done in the form of input to output.
  3. When a hash function is collision resistant if it is impossible to find two inputs that hash to the same output.
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#2910

Describe hash functions with your own words

A hash function is a one-way mathematical algorithm, which takes an input and will return an output (always the same result for the same 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).

In bitcion, hash functions are used to hash the transactions which will be inserted in the blockchain.
Each block in the chain is hashed. This hash is part of the input of the next block. So every block hash depends on the previous blocks.

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 there can’t be 2 inputs with the same hash output. So every input-ouput should be unique.

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#2911
  1. Hash functions allow you to go from input to a unique output, but does not let you go from output back into input.
  2. Hash functions for bitcoin are based on SHA256 & this hashing algorithm takes the data set and outputs a unique alphanumeric 64 digit number. If any part of the input varies, it will then produce another unique output.
  3. 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 such that H = H, and a ≠ b.
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#2912

[quote=“ivan, post:1, topic:8430, full:true”]
Homework on Hash Functions - Questions

Homework on Hash Functions - Questions

  1. Describe hash functions with your own words.

it a a means to mutate, change in encryptic alfa numeric maner anything,…it is ia one way street due to the nature of the Elliptical Curve Cryptographer,… it is irreversible code data. You can use it to code just a lette, a name, a phrase or even a bunch of data a file, a transaction anything that can be expressed in any language

  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 can be use in very many application, in financial transaccion, in supply chains, in email identity protection, in peer to peer money transfers or remittances or consignments, I need to research to see if Smart Contracts use them,… wait yes!!! I think that it is a MUST, due to the privacy liabilities, in the there nature of a contract for payment and verification. In the Medicine industries in al industries well need to learn more on how it is used or applied well in casino business in the video game industries just about every part of all of our human activities except for maybe making babies.

  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).

Collision Resistance I got carried away it fascinated me,… Well this is what I concluded it all is related to the Nature of computer input each is unique, (in the event , or for the event of each input) even if it was the same item or even a letter, that is being Hashed the computer will input and output only one at a time the first item or if you want a letter, it is input at a certain specific moment in time, whatever the time frame (I tried it,… Open two Tab in the web site that Ivan introduced us, the one that generates Hash,… well I had my two windows open in the same computer and tried to Hash the letter Y, I tried to be very, very synchronicity wise at the moment that I press Hash for both Tab one would be faster the the other, until it stalled so I had to turn it off and well) it can be, that the key to Collision Resistant. when you put the second item you key in “Y” and “Y” and “Y” again and again, “Y”, “Y”, “Y” in it will register a different digital signature due to the SPACE/TIME the moment and the space influence the effect OF THE UNIQUENESS in the Elliptical Curve Cryptographer so that makes it “COLLISION RESISTANT”, it is **unique Digital finger print EACH TIME… and there is only that one Hash different unique,… that is generated for each time you ask for “Y” and you Hash it will be a different Hash will be different. No CLONES, No Copies, No Plagiarism, No counterfeits, it is Trustless ! !

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