Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#1972

1, A private key is personal to you while your public key is your personal key to the public to see/use. The private key is random numbers created and through the numbers you can create more random numbers that creates the public key. It’s all a way of encrypting transactions/messages etc and you can only generate/see the public key through a private key and never the other way around. To make it simple, when you want to encrypt information you want to send you’ll need the public key for that and the private key is used to decrypt that message.

  1. For encryption and digital signatures when secure communication is needed or the need for verification.
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#1973

We use the elliptic curve function to derive the public key, however the public key is hashed to get the address :slight_smile:

#1974

  1. a private key is a large number generated by your computer that can be used to sign transactions or unlock messages that were sent to you that have been encrypted by the public key relative to your own private key.
    the public key is a number that was generated by your private key through a long formula. People use this public key to send messages.

  2. encryption and digital signatures

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#1975
  1. Private keys are generated by your computer when you open up a wallet. The private key is what you use to sign that transaction. Private keys are almost impossible to generate copies from different accounts but if someone were to access your private key, they would have access to your funds. If you lose the key you would also loose access to your funds. The private key creates the public key. People can verify a transaction by checking the public key against the payment signature. If someone is sending a payment to you, they would send it to your public key address, or your bitcoin address. You access and spend those from with your private key. A private key, public key, and bitcoin address are mathematically linked, originating at your private key. It is impossible to find your private key based on your public key due to the fact that SHA-256 is a one way encryption system.
  2. Encryption and digital signatures.
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#1976

  1. Public and private keys are used as assurance that transactions are conducted safely and verifiably. A public key is generated with the use of a private key, using elliptic mathematical operations. The public key is used to interact with other people on a network openly, to send and receive information and other services. Public keys are used by others to identify ownership, and to transfer valuables to the owner of the public key. Private key is a extremely large random number. A private key is personal and it must be safeguarded with utmost care. The private key provides an address which can be subject to verification as proof of sender. It is used to encrypt messages.

  2. Public key cryptography can be used for signature verification, to identify individuals or an entity in a transaction. Its also used to generating digital signatures. It uses a pair of keys to encrypt and decrypt data in order to protect unauthorized access or use.

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#1977
  1. Describe the concept of public and private key with your own words.A private key allows for the owner to sign off on cryptographic transactions. In order to do so a (one-way) hash function will use the private key to generate a public key, keeping your private key secure and private. The public key then creates an address that can publicly used on the blockchain network for transactions, while maintaining sign off control by owner’s private key.
  2. What 2 use-cases can public key cryptography be used for? Encryption and Digital Signatures
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#1978
  1. Public key encrypts the wallet–large number combination meant for their eyes. Private key decrypts the wallet–is meant only for your eyes.
  2. Two use cases of public key cryptography: encryption and digital signatures. In encryption, Alice sends a public key-encrypted message/funds to Bob, which he decrypts with his private key. In digital signatures, Alice sends a message/funds to Bob, which he verifies via her digital signature + public key. With Bitcoin, digital signature is used to identify/verify sender: when Bitcoin is sent, your private key digitally signs that transaction so that everyone can see that you sent the message/Bitcoin.
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#1979
  1. A private key is a random number generated on your computer, a mathematical equation is used to generate a public key. The public key can be seen by “spectators” as the number can’t be used to generate a private key, this only works one way.
  2. First use case is for encryption like encrypting a message and second case is to identify integrity through a digital signature
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#1980

  1. Private key is a random, unshareable number generated by the computer for its owner to use only. Public key is derived from a private key for public use and encryption of messages. The encrypted messages with the specific public key can be decrypted only by appropriate private key. There is no way to know the private key from the public key - it is one way function.

  2. Two use cases:
    2.1. Encryption - to encrypt sensitive information which can be decrypted only by specific private key.
    2.2 Digital Signatures - for sender to sign message with private key and for receiver to verify the sender from appropriate signature and public key

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#1981

what is the elliptic curve function?

#1982

a private key a large number generated by the internet which is used as your private signature to send and receive your bitcoin on the blockchain, they public key is generated by your private key and can be seen by the public of which your private key is not for the public

public key cryptography c an be used for Encryption and digital signatures.
Digital signatures [private key] verify that you have personally sent bitcoin to a receiver

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#1983

  1. A private key is a randomly generated string, and the public key a different string generated using the previously generated private key.

  2. In cryptography, we can use the private/public key pair to encrypt messages and to sign transactions.

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#1984

We use the elliptic curve to derive public keys :slight_smile:

#1985

Its a function that can be represented as a curve on the coordinate system. It usually has a function like (k + j)H = kH + jH, where:
kH = PubKey
k = PrivKey (this is the number of transformations on the curve)
j = shared secret
kH + jH is publicly know
By using this function you can prove you know k by providing the solution to k + j without revealing k

A video that probably explains it better, posted by one of the students: :stuck_out_tongue:

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#1986

Thanks a lot!! This helps

#1987

1- The private key is a random number generated by a computer, with this private key through a mathematical formula the computer generates a private key, its infeasible to get the private key through the public one.
2- We can use a public key to send data to a private key. Without geting to know that private key!

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#1988

  1. In public key, the public key is used for encryption, as the private key is used by the receiver for decryption.

  2. For transactions and payments, secondly digital signatures are used the most to verify who sends a particular message.

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#1989

  1. Describe the concept of public and private key with your own words.
    A public key is generated by the private key to be a unique identifier in the crypto world. Just like hash, private keys can generate public keys, but public keys cannot be reverse engineered to determine the private key that generated it. The private key has all the power to sign signatures or messages, while the public key is simply one that is posted on the blockchain for everyone to see. I think of the public key as my routing and account number in a traditional centralized bank, while the private key is the correct combination of my account ID and password, or my ATM debit card and my PIN number. The former does not have any authorization and can be used by the public to determine where they could send funds to; while the latter (the account, password, card, and PIN) has the authority to make and sign transactions.

  2. What 2 use-cases can public key cryptography be used for?

  • encryption
  • digital signatures
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#1990
  1. Describe the concept of public and private key with your own words.

Public keys are used to display information that is available for the whole world to see. Private keys are used to decrypt data specifically for those who hold the key.

  1. What 2 use-cases can public key cryptography be used for?
  1. Encryption
  2. Digital Signatures
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#1991

You don’t really use the keys to send data. You can use them to either encrypt data to be sent over an unsecured network (the internet) or to sign a message to prove its origin. In short encryption and digital signatures :slight_smile:

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