Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#3946
  1. Describe the concept of public and private key with your own words.

Public key is public and you can share it. Private key is hidden due to its features and tasks.
You generate a PRIVAT KEY which is a random number. U use a formula to derive a PUBLIC KEY from that PRIVAT KEY. You send a message to ALICE and you sign it with your PRIVATE KEY. The receiver (ALICE) can check if this is your message by checking if the PUBLIC KEY and the signature are matching the PRIVATE KEY because when you send a Bitcoin transaction, your PRIVATE KEY signs that trx, so everyone can se that you spent that Bitcoin
There is no way to derive a PRIVAT KEY out of a PUBLIC KEY. Due to this, it is a one-way function

  1. What 2 use-cases can public key cryptography be used for?
    Encryption and digital signatures
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#3947

  1. Describe the concept of public and private key with your own words.
    The public key is derived from a private key. The private key is a random set of numbers that a generated by a person or a computer. This process is again unidirectional, meaning that with the same private key (input) you will get the same public key (output) but one can not derive the private key from the public key.

  2. What 2 use-cases can public key cryptography be used for?
    It can be used for encrypting messages/information or for digital signatures. The former works by using the public key to encrypt messages only the owner of the private key can decrypt. The latter is done by using the private key to create a signature (like in the crypto wallet). This signature can then be verified with the public key. This is done by a mathematical verification process that shows that the signature was created by the private key that also generated the public key.

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#3948
  • Private and public-key encryption is a way to obfuscate data from anyone without a private key. Similar to hashing, an input is provided and encrypted with the public-key generating an encoded output. A private key allows you to decrypt the encoded data and see the information.
  • Public-key cryptography allows anyone to send data using the public key. A public key can never be reversed and compromise a private key. A private key allows only the user to decrypt the data obfuscated by the public key.
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This process can be reversed to verify private keys/digital signatures. Encrypting data with the private key can be decrypted by the public key.

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#3949
  1. Describe the concept of public and private key with your own words.

Your public key can be seen by everyone in the network. Your private key creates your public key and you should not share it with anyone and keep it safe.

  1. What 2 use-cases can public key cryptography be used for?
    Sending a encrypt message or sending funds. Digital Signatures
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#3950

Functions, Hash Functions, Cryptography

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

  2. Public key is like the mailing address where anyone can send you correspondence

  3. Private key is like the safe in your house that has a code that only the owner of the safe will know and no one else.

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

  5. Encryption

  6. Digital signatures

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#3951

  1. The concept of public and private keys are generated by your computer to enable you to send and receive encrypted messages.

  2. 2 use cases for public key cryptography are encryption and digital signatures.

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#3952
  1. Describe the concept of public and private key with your own words.
    A private key is generated by your computer first using random number, then a public key is derived from the private key. You can give your public key out to others to send you money. Your private key will then decrypt it.
  2. What 2 use-cases can public key cryptography be used for?
    Encryption and Digital Signatures
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#3953

  1. Describe the concept of public and private key with your own words.
    A private key is a randomly generated sequence of digits that gives you authority to sign outgoing transactions.
    A public key is a sequence of digits generated from your private key that cannot be back-calculated and allows the private key holder to send encrypted messages or create wallet addresses.

  2. What 2 use-cases can public key cryptography be used for?
    Encryption and digital signatures.

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#3954

  1. public and private keys have 2 functions, encryption and digital fingerprints.

  2. Use case number 1 - When sending encrypted messages. Bob sends a message with his public key and Alice is able to read it with her private key.

Use case number 2 - Digital Signature. Bob can verify that the signature is from Alice by using his private key or by seeing that Alice used her public key to sign a document.

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#3955

Describe the concept of public and private key with your own words.
Private key is generated by the computer to encrypt and send a message. The private key is can decrypt the message as well.
Public key is an address that anyone can send message or information to.

What 2 use-cases can public key cryptography be used for?
Encryption and Digital Signature

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#3956

  1. A private key is used to create a public key that is visible on the blockchain. A person can take your public key and digital signature hashed from your private key (in Bitcoin) to receive and verify a message is from you.

  2. Encryption and Digital Signatures

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#3957

You explained how it works and mentioned encryption. But PK cryptography can also be used for digital signatures which is heavily used in cryptocurrencies. :slight_smile:

#3958

  1. Encryption is unidirectional, you can decrypt the public key with a private key but not another way around. In crypto, we use our public key (that is generated from our private key) to generate our Bitcoin address, and use the private key to sign transactions.

  2. The 2 major use cases for public key cryptography is Encryption and and Digital Signatures

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#3959
  1. A private key is a randomly generated number which is hashed in to a public key. The private key cannot be derived from the public key, but anything encrypted by the public key can only be decrypted by the private key, and NOT the public key.

Wallet—random Private key—random Public key—BTC adress

  1. For encryption and digital signatures.
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#3960
  1. Describe the concept of public and private key with your own words.
    A private key can be used to sign a message or transaction. It can also be used to generate a public key. You can decrypt the public key with the private key, but not the other way around. It is a one way street. The public key can be used to generate your bitcoin adress.
  2. What 2 use-cases can public key cryptography be used for?
    The 2 use-cases for public key cryptography are encryption and digital signatures
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#3961

Thank you for the reply, it made me realise that you can reverse that process to verify singnatures/private keys.

Input > Private key < Public Key

#3962

  1. A private key is personal ( keep it secret ) and can de-crypte messages or generate signatures. A public key is generated from the private key. The public key encrypt messages that can only be de-crypte with the private key.
    Signatures generated with the private key, can only be verified by the public key.

  2. To encrypt messages or verifie signatures.

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#3963
  1. Describe the concept of public and private key with your own words.
    -Public keys are used in encryption to receive information. Private keys are used to decrypt the information that has been received as well as to send information to another public key as well as generate signatures. Private keys can generate public keys but public keys cannot generate private keys.
  2. What 2 use-cases can public key cryptography be used for?
    -generate digital signatures to receive information and authenticate identity
    -encrypt information to be sent to another public key
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#3964

Homework on Public and Private Keys - Questions

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

Concept is based on idea that one can use publicly available information of one party to hide content and allow only this party to read content.

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

It can be used for encryption and digital signatures.

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#3965

  1. First of all, public key is generated from private key. Public cannot be traced back to it private key.

  2. To encrypt message in order to ensure only receiver will be able to encrypt back using his private key. Also it’s widely used in crypto such as Bitcoin.

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