Homework on Hash Functions - Questions

Blockchain and Bitcoin 101
#4299

1Hash functions are one way functions where each input produces an output or digital fingerprint, each result is unique.
2 it makes each Bitcoin unique
3.Collision resistance means that is very difficult to find 2 inputs that produce the same output in a hash function. This is an important property in cryptographic hash functions.

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#4300

1: Hash functions are unique inputs that produce a unique output.

2: Hash functions are used in crypto to secure the network from outside attacks.

3: Collision resistant means that it is hard to find two inputs that produce that same output.

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#4301
  1. Describe hash functions with your own words
    Hash functions work by generating a unique output from any given specific input that can not be reverse engineered. You can not discover the input after finding an output because inputs are converted to a binary sequence which is then pushed through SHA-256 to generate a completely random output in a base16 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).
    Hash functions are used in cryptocurrencies like bitcoin in mining. When adding a block to the blockchain you must solve for one of these hash functions will an insane about of possibilities. When solved the block is added to the chain producing an output that will be at this point impossible to reverse engineer ensuring that all transactions on the blockchain are valid safe secure and irreversible
  3. 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).
    It means that no two inputs can ever spit out the same output. This is important so that multiple inputs can never be placed on the blockchain, meaning that inputs can ever be replicated in order to cheat the blockchain. It is important so that there is no means of fraud on the blockchain and that all transactions are indeed unique and can not be replicated.
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#4302

1. Describe hash functions with your own words?
1.A. A hash function takes in data and processes the data through an algorithm to create a unique fingerprint specific to that data.

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).
2.A. Hash functions are used in mining from transaction blocks, keys pairs to merkle trees to ensure verifiable data and hard encryption.

3. 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).
3.A. Collision-Resistant hashing is a term used to describe the low possibility of hashing the same fingerprint or output of two or more differing data sets. Due to the random nature of hashing, its possible for one or more outputs to be the same. SHA256 is more Provably secure than SHA1 and MD5 making it just as hard to solve the encryption.

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#4303

1.hash function is a one way input that creates and output digital fingerprint that cannot be reversed.

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

  1. 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 ā‰  b but H ( a ) = H ( b ).[1]:136 The pigeonhole principle means that any hash function with more inputs than outputs will necessarily have such collisions;[1]:136 the harder they are to find, the more cryptographically secure the hash function is.
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#4304

  1. A hash function is used in cryptography to map an input of any size to a number which has a specified number of digits.

  2. Altering the bitcoin ledger by a dishonest node would require successfully hashing the altered ledger to the target value. This would require an immense amount of computing power greater than the combined power of the honest nodes. Therefore hashing helps secure the bitcoin network. Hashing is also used to generate private and public keys.

  3. A hash function H is collision-resistant if it has a unique output for every different input.

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#4305

it is a one way function that consists of a coded message and that message cant be viewed unless you have the hash code

Hash functions are used by miners to solve transactions to receive rewards for there work

If the hash functions are not collision free then we would run to the problem of miners confirming the same hash functions twice

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#4306

  1. Describe hash functions with your own words
    Each unique input gives a unique output and a hash function is oneway only ( input - 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).
    In Bitcoin protocol, hash functions are part of the block hashing algorithm which are used to write new transactions into the blockchain. Thru the mining process, its the need for this large amount of processing power that means new Bitcoin get mined over a long period of time, not all at once.

  3. 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 is the property of a hash function that it is computationally infeasible to find to colliding inputs.

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#4307

Homework on Hash Functions - Questions

  1. Describe hash functions with your own words

  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).

  3. 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).

  4. Hash functions work by taking a set of inputs, of any size, and producing as output some for of table or other data structure, that contains fixed-size elements.

  5. In cryptocurrencies hash functions can be used to guarantee authenticity of data, when they are designed to resist attacks from malicious sources. A hash function in Bitcoin is used to hash transactions in each block. Since each transaction has a unique output the blockchain becomes very secure.

  6. Collision resistant means that two inputs cant have the same output.

#4308
  1. Hash functions work by taking a set of inputs, of any size, and producing as output some for of table or other data structure, that contains fixed-size elements.
  2. In cryptocurrencies hash functions can be used to guarantee authenticity of data, when they are designed to resist attacks from malicious sources. A hash function in Bitcoin is used to hash transactions in each block. Since each transaction has a unique output the blockchain becomes very secure.
  3. Collision resistant means that two inputs cant have the same output.
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#4309
  1. Describe hash functions with your own words
  • Hash functions are one way functions where each input produces an output or digital fingerprint.
  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).
  • The transactions are taken as input and run through a hashing algorithm, such a SHA-256, which gives an output of a fixed length.
  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).
  • It means to reduce the chance of having two different Input that will result of as same output, almost infeasible.
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#4310

  1. A function which takes a set of data and creates an output.

  2. Hash functions are part of the block algorithm within bitcoin and form part of the mining process in which new blocks are mined by mining computers solving algorithms via a public network in order to create more coins.

  3. Collision resistance is the property of a hash function that it is computationally infeasible to find two colliding inputs

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#4311

  1. Describe hash functions with your own words
    Hash Functions takes input in form of numbers, alphabets, pictures and videos and convert into alphanumeric characters.

  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 generates blocks of data and it adds up more block of data as more nodes participate.

  3. 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).

Hash functions should not be decoded or decrypted.

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#4312

  1. Hash function is a one way function where a unique input will generate a unique output. You can cannot go from output to input.

  2. Hash functions are used for mining where the outputs of the hash function must be the target.

  3. When two inputs cannot equal the same output.

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#4313

  1. Describe hash functions with your own words.

    You can take an input, put it through a hash function and get a unique output. You cannot go from 
output to input unless the hash function is broken. Once you change a single bit in the input, the 
output will be completely different so it is easy to spot if the data was tampered with.

  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).

     In mining, you have to come up with a hash function that has a certain number of zeros starting at 
 the beginning of the output of the function, this is what is needed to create a single block. This 
 takes a lot of computational power and thus, electricity. This is also what gives bitcoin, its security 
 because to add some new information to the blockchain, requires a lot of resources, and once 
 you put all of this information out there, everyone on the network has to agree with it.

  3. 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 is how hard it is to break a hash function using brute force attack and also it 
   should not have 2 inputs that would give an identical output, ideally it 
   should cost more resources to break a hash function than there is to be gained in case the hash 
   the function is broken and the information within is revealed.
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#4314

  1. Hash functions are functions that us a unique input to get an output which is stamped with a hash (finger print of input)

  2. Has functions are used to write new transactions into blockchain through the mining process.

  3. Hash functions need to be collision resistant meaning that youā€™re unable to break the algorithm buy taking a unique output to solve for multiple unique inputs

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#4315

  1. Hash functions are one-way functions, where each unique input gives a unique output and itā€™s not possible to get the input from the output.

  2. In the bitcoin protocol, 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 resistant is a property of cryptographic hash functions, which means if it is hard to find two inputs that hash to the same output

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#4316
  1. Hash functions are taking data and creating a unique fingerprint for it. This process makes reversing the transaction impossible.
  2. In the case of Bitcoin, hash functions are used to file away transactional data. Only the intended recipient can decrypt this based on the use of keys.
  3. This means that two different sets of data do not receive the same hash, ever.
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#4317

  1. A hash function is a universal translator that takes data and translates it for computers.

  2. They are used in the mining process of (PoW) protocols to generate new blocks on the blockchain.

  3. This means that it should be difficult for two hash functions to produce the same output.

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#4318
  1. Hash function is a function that has a deterministic characteristic. It means that any given input will give a unique output. Even the slightest changes in the input will create totally different output. But the same input will give us the same exact output all the time. Second, it is a one-way function that means you can only get the output from the input without being able to reverse the output to figure out the input. This means that from the output, it is virtually impossible, or mathematically and computationally improbable, to determine what the input is.
  2. It is used to create a public key from a secret key for example.
  3. A collision is when a hash function produces the same output, for more than one input. If hashing data1, for example, a spreadsheet, and hashing data2, which for example a picture, produce the same output, then a collision has occurred.
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