Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#4928

I am not sure if I understand your answers well🤔.
The two cases are encryption and digital signatures.
You can sign a message (or transaction) with your private key and everyone that knows your public key can verify that you are the signer of the message.
The other use case is encryption, this one is not used in Bitcoin, but someone can use your public key to send you a hidden message over an unsecured network (the internet) that only you will be able to decrypt and read with your private key.

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#4929

1. Describe the concept of public and private key with your own words.
A private key is a random computer-generated number that in turn creates a public key.
The public key is visible on the blockchain to anyone and acts as the wallet address like a bank account number.
The private key is a secret number that is used to prove that you own the wallet address and allows you to spend what’s inside. Your private key cannot be generated through your public key, so as long as you don’t share your private key, your coins are safe. If someone gets your private key they can steal your coins.

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

  • Encryption of messages and information
  • Digital signatures for identification
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#4930

A private key is a string of random unique numbers generated by your computer and can be used to encrypt or verify information or data. A public key is also generated by your compute but is derived from your existing private key. A public key can be verified mathematically through comparing digital signatures and and a private keys… if I understand this correctly.

Encryption and information verification

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#4931

  1. Describe the concept of public and private key with your own words.
    Because in the bitcoin network there is no central authority that keeps track of all transactions, this must be done by the wallets in the network, and each wallet is based on a public-private key pair.
    The private-public key relationship is at the center of what makes blockchain secure, transparent, and verifiable by everybody in the network.
    In cryptography, the private and public keys are very large, random numbers, that are generated by a computer.
    The private key is meant to be kept secret by those who generate it, because it is their only way to retain access and control their transactions (messages, money), without external interference.
    The public key is also generated by a computer and derived from the private key, .

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

Encryption
In the scenario where 2 parties want to communicate privately in an open and unsecured environment, each one of them need to alternate between 2 roles: the receiver and the sender.

  • the receiver: generates (through a computer) a private key (that he keeps secret), and through a special formula, generates another key (public key) that is based on the private key. The receiver then shares the public key with everyone (on the Internet) and awaits the messages from the sender.
  • the sender: makes the message private, unreadable (encrypts it) by using the receiver’s public key, and sends it to the receiver.
  • the receiver: in order to read the encrypted message, uses the private key and decrypts it. Only those who have the private key from which derived the public key used for encryption, can decrypt the messages.

Digital Signatures
It is a more important use case for cryptocurrencies than encryption, because it is used to verify who sent a particular message.
And this crucial because when someone sends a BTC TX, her/his private key signs that TX so that everyone in the network can see that it was her/his TX to spend and no one else’s.

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#4932

Homework on Public and Private Keys - Questions and Answers

  1. Describe the concept of public and private key with your own words.

    Public key infrastrcuture (PKI) leverages asysmetric encryption in the fact that every node/person requires their own public and private key though simply with these two keys they can securely talk with anyone else.

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

    Secure communication with nodes in a network topology. Cryptocurrency :slight_smile:

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#4933

1,2. Public and private keys are unique keys that are used for security and identification. A private key can act as your digital signature that lets the network verify your transactions are authentic. A public key can be used by others to send you encrypted data that you alone can access with the use of your private key.

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#4934
  1. Private key is a large randomly generated number and is working as a kind of proof of ownership of the derived public key. The public key refers to the private key but is impossible to use in order to access the private key.
  2. Encrypt messages so that only the owner of the private key is able to decrypt messages that were encrypted using the corresponding public key.
    Sign documents using the private key and sharing the public key for others to verify the digital signature.
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#4935

  1. Public and private keys are used in cryptography to encrypt and decrypt information. The public key of person A is required by person B in order to send person A an encrypted message. Person A then uses their private key to decrypt the message sent to them by person B.

  2. Encryption and Digital Signatures

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#4936
  1. Describe the concept of public and private key with your own words.
    Private key is just a huge random number which we’re using to decrypt messages, if you lose private key - you lost all your coins. Public key is derived from private key and is used as your public address from where people can get in touch with you and send you data. If I want to send a message to Vitalik I would need to know his public key in order to encrypt my message.
  2. What 2 use-cases can public key cryptography be used for?
    First one is encryption - If I send a message to Vitalik, I am going to encrypt message with Vitalik’s public key. In order for him to see my message he will decrypt my message with his private key.
    Digital signature - when we send message to someone, we use our private key to sign it, so that that someone knows that message has came from us and not someone else.
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#4937

  1. Describe the concept of public and private key with your own words.
    -> a public key gets calculated from a private key and is made public. The owner of the associated private key, can prove that he created this public key without sharing his secret private key.

  2. What 2 use-cases can public key cryptography be used for?
    A)To send encrypted messages via an unsafe/public network, so that only the recipient can decipher it
    B) digital signatures, whereby the owner of a private key can prove that he signed something without having to disclose the private key

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#4938

  1. A public key is derived from a private key. The public key is, in my opinion, better described as a lock, which can be unlocked only by its corresponding private key, for decryption or identity verification.

  2. Encryption & digital signatures.

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#4939

  1. Describe the concept of public and private key with your own words.
    Private key is randomly created, with this key you can create a public key, that can be shared. with private key you can sign documents or decrypt any data that was encrypted using the public key, private key as the name suggest, should never be revealed to anyone.

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

a. digital signatures - using the private key you can sign documents that can be verified by others that you are the source.
b. encryption - for example message.

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#4940

  1. You create a privat key this one is save and should never be shared. From this on its possible, threw a a one way funcion, to create a digital siganture and from this one you can create a public key. The public key can be shared everywhere. Its posible to tell threw a mathematic formular that the public key and the sigature are created from the same privat key. With all of that you can encrypt and decypt massages.

  2. 1.encryption 2.digital signatures

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#4941
  1. Public key is generated from a private key. Public key can be shared around on the network but it can only be unlocked by a private key. Sharing your private key means giving away the key to your public key which leads to your bitcoin in this instance.
  2. A. For digital signature B. Message encryption
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#4942

1. Describe the concept of public and private key with your own words.
Private and Public keys are strings used in encrypting and hashing (creating a signature) functions; the Private key is a key that is meant to be kept hidden (private) from everyone else, whereas the Public key (which is derived from the Private key) is meant to be shared with anyone. When hashing an input with the Private key, you can hash the same input with the Public key to match the output, this can be used to verify a message came from a specific person.

2. What 2 use-cases can public key cryptography be used for?
Public key cryptography can bed used for encrypting raw text in order to send it securely to another person, as well as for creating a digital signature for raw text to be used to verify if a message has been tampered with or not (as well as if it came from a trusted source).

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#4943
  1. To me a private key is like a master invisible key. It can unlock what a Public key is meant to hide. Being that it is invisible, no one can find out the Private key (assuming it isn’t physically stolen, or spotted online). The public key comes from the private key, you can use the private key to get to the public key, but you cannot get the private key from looking at the public key.
  2. You can use the process of encryption to “encrypt” messages. The public key is used to secure or “encrypt” messages, they are only secured through the private key though. Digital signatures are another use case. In a transaction, you use a public key and a “digital signature” to complete the transaction, however the private key is needed to confirm that the complete transaction is true. It is never seen, but it is needed to verify the transaction.

Blockquote

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#4944

Hello all!

  1. Private keys are generated by your computer randomly and are intended to be only known by the user and are also used to generate public key which can be safely seen by the world and other users.
  2. Public key cryptography can be used to verify a certain person is encrypting a message or when sending transaction to a specific person.
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#4945

1.) When you want to make a bitcoin wallet you generate a private key who is large random number of digits, from the private key i get the public key and from the public key i get the bitcoin adresse. its impossiblke to get from the bitcoin adress to the private key, you only come from the private key to bitcoin adress. If i want to make a transaction i sign the transaction and the recipient can with the public key from the sender verifiy that the transaction really comes from the right person.

2.) encryption and digital sign, but for cryptocurrencies mostly used the digital sign.

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#4946

  1. The public key is public for everyone to see. Its generated with the private key. The public key can not be used to generate the private key.

  2. Its used for encryption and signing.

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#4947

  1. Describe the concept of public and private key with your own words.
    As there is no central authority that manages any of the accounts (aka wallets) in a blockchain network, the PUBLIC and PRIVATE key pair is at the core that makes the blockchain/cryptocurrency industry possible.
    The PRIVATE key is a large random generated number that a user keeps secret. Through a special formula, the PRIVATE key creates a PUBLIC key. Currently, there is no way mathematically that you can use the PUBLIC key to determine the PRIVATE key.
    !IMPORTANT!: If you lose your PRIVATE key, you can’t sign any transactions and you have lost your coins. -OR- if someone steals your PRIVATE key and is able to “sign” the transaction for you, they have stolen your coins.
    The PUBLIC key is shared on the internet (shared with the public).
    Today’s BITCOIN network utilizes a 3-step process: (1) wallet generates the random PRIVATE key number (2) PRIVATE key generates the PUBLIC key (3) PUBLIC key generates a BITCOIN address (NOTE: this 3rd added step was a necessary security feature from 1st implementation of BITCOIN).

  2. What 2 use-cases can public key cryptography be used for?
    (1) Encryption (2) Digital Signatures
    Use Case #1: ENCRYPTION
    User1 encrypts their message with User2’s PUBLIC key. Now that it is encrypted, nobody can read it, with the exception of User2 by providing the PRIVATE key.
    User Case #1 is not used in Cryptocurrencies.
    Use Case #2: DIGITAL SIGNATURES use PUBLIC and PRIVATE keys in a different way.
    Digital Signatures allows you to IDENTIFY yourself and ensures INTEGRITY of a message.
    User1 encrypts their message with their own User1 PRIVATE key to sign the message. User2 takes User1’s PUBLIC key, compares User1’s PUBLIC key with User1’s PRIVATE key signature to confirm its validity, then is able to decrypt the message.
    When SENDING in BITCOIN, you use your PRIVATE key to “sign” the transaction.
    When RECEIVING in BITCOIN, people send funds to your BITCOIN address, which is linked to my PUBLIC & PRIVATE key pair.

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