Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#3784

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

    Public and private keys as a pair, are used to encrypt and decrypt messages sent between two people in a public and unsecure network, where the private key is randomly created, and the public key derives from the previous.

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

    ENCRYPTION - The ability to send private messages through the network.

    Practical example:
    Person A wants to send a message to person B.

    • Person B generates a private key from which it derives a public key
      (At this point person B has access to the private key, and everyone else to the public key)
      • Person A encripts the message with person B public key and sends it
        (The message becomes encrypted and impossible to read)
        • Person B reads the message using the private key

    DIGITAL SIGNATURE - The goal is to verify the sender’s identity (no encryption required)

    Pratical example:
    Person B wants to verify that person A sent the message

    • Person A generates a private key from which it derives a public key
      (Again, the public key can be access by everyone at this point)
      • Person A uses the private key to send the message to person B
        (Person A has created a unique signature by linking the private key to the message)
        • Person B receives the message signed, and compares the signature with the public key to see if it corresponds with the private key

P.S - This was a tough one to resume… :upside_down_face:

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#3785

  1. Describe the concept of public and private key with your own words. - public key allows people to encrypt a message when sending transaction between each other and the private key can decrypt the message

  2. What 2 use-cases can public key cryptography be used for? - encrypt messages and verify transaction sender via digital signature

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#3786

Describe the concept of public and private key with your own words.
A private key is a randomly generated number which is used unilaterally to hash a public key. The public key can be used publicly, such as on websites, to receive messages and transactions. The public key is derived from the private key, and the private key cannot be deduced from the public key.
What 2 use-cases can public key cryptography be used for?
Encryption - to add a layer of security and privacy to messages on a public form. And digital signatures, which is used for identity verification of the source of the sender.

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#3787
  1. Public key is generated by a private key and when using that public key to encrypt the information only its private key can decrypt the encrypted information.

2 Encryption and Digital Signature.

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#3788

  1. A private key is used to generate a public key. The public key can be used to encrypt information and the private key can be used to decrypt it again. However, a public key cannot be used to figure out what the related private key is.

  2. It can be used to encrypt data/messages, as well as to create a digital “signature”.

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#3789

  1. Describe the concept of public and private key with your own words. Private key is a randomly generated number that is to be kept secret and very safe and what identifies me while public key is derived from my private key and can be shared with others but the private key can not be traced back from the public key.

  2. What 2 use-cases can public key cryptography be used for? Encryption and digital signatures. Encryption - Used in emails and public, public key (generated by the randomly created private key) available for all to see yet only the private key holder can receive/decode the messages. Digital Signatures. Uses private key of sender to verify identity of sender by using public key to verify that the private key actually was derived from same source. Then public key ( generated from private key) is used to create wallet like bitcoin wallet to buy/sell coins.

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#3790
  1. Describe the concept of public and private key with your own words.

A private key is a randomly generated unique number that is used to access some time of information. A public key is a number generated beginning with your private key.

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

Digital coins. Encrypted messeges.

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#3791

  1. Describe the concept of public and private key with your own words.
    Public key is generated from private key. Private key gives ability to either decrypt or put a signature.

  2. What 2 use-cases can public key cryptography be used for?
    to decrypt encryption or to use as a signature.

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#3792

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

The private key is only your own to see and you must hide it safely. The public key is free for everyone to see and it’s safe since you can as in a function never go back to figure out the private key from the public, as the public is made from the private in this one way function way.

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

  • Encryption (ie messages, the message is encrypted with the sender’s public key, and the only way to decrypt is with the senders private key).
  • Digital signiture (personal id and integrity). (signing with private key).
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#3793

The use of public and private keys allows for the secure transfer and corresponding of transactions and messages between independent parties without the need of a central authority. The private key is only known to the one party, hence it is private and must be secured. The public key is an address that anyone can. The combination of using public key with private keys is the combination that makes it a secure system. While am I more clear about the concept now, i still need to review to get more clarity on how the decryption of the message or info by the receiver occurs.

Public key cryptography can be use to send and receive secure messages or to digitally sign transactions. Bitcoin primarily uses the second use in its ecosystem.

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#3794

  1. Describe the concept of public and private key with your own words.
    with a public key you can only encrypt anything but not decrypt , to decrypt it you need private key

  2. What 2 use-cases can public key cryptography be used for?
    digital signature and to verify transaction

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#3795

Can someone confirm or clarify (at the highest level) if my understanding of the concept as described below is correct at a high level? (or if someone has a better analogy)
I am trying to find a simplified analogy to use when explaining to other. (similar to the analogy of hash function with blender and ingredients)

The bitcoin address is similar to the address on a home. (number, street, city, state, zip). In order to get into the house you need the private key which allows you inside the front door.
The combination of the private key and public address creates a digital signature which has characteristics that lets the receiver of the digital signature know that the info came from the inside of the home.

#3796
  1. Describe the concept of public and private key with your own words.
    The private key is a random number which is generated and it is used to derive the public key. Public key is visible to everyone and is used to generate an address. Private key->public key->address is unidirectional which means that there is no way to derive the private key from the public key or address. The private key is used to sign transactions and if it is disclosed or shared with someone, one can loose their bitcoin
  2. What 2 use-cases can public key cryptography be used for? encryption and digital signatures
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#3797

You’re on the right track, I would say digital signature is like a watermark or a seal that can be verified by the receiver to be sure the message is from a valid sender. :slight_smile:

#3798
  1. Describe the concept of public and private key with your own words.
  2. What 2 use-cases can public key cryptography be used for?

A.1. Public and Private Keys are terms used in encryption and decryption of sensitive information, and the creation of digital signatures.

Public Key—Bitcoin public key is a cryptographic system that uses pairs of keys i.e. Public Keys and Private Keys. Both Public and Private Keys are used to encrypt and decrypt data. However, Public Keys are used for identification purposes and to ensure data integrity.

Private Key—Bitcoin private key is a secret number randomly generated by a computer. This allows users to encrypt and decrypt data i.e. send and receive Bitcoins. When a Bitcoin address is issued it also contains a Bitcoin Private Key. As the name indicates, Private Keys should be kept safe and secure as these are also used for authentication purposes. Private Key cryptography is faster than Public Key cryptography mechanism.

Note: The security of the Blockchain system concerning Private Keys comes one-way that is getting from the Private Key to the Bitcoin address. It is not possible to trace back the Public Key from the Bitcoin address; likewise, it is also not possible to trace back the Private Key from the Public Key.

A.2. Public Key cryptography use-cases are as follows:

Case 1: Encryption and decryption of data
Case 2: Digital signatures (recipients identification and ensure data integrity)

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#3799
  1. Describe the concept of public and private key with your own words.

Private key – is a secret key that I keep for myself. Public key – is to be shared with others. When this public key is used to encrypt messages on another side – only me with my private key can de-crypt it.

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

Encryption and Digital Signatures.

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#3800

  1. Whatever is encrypted by the public key can only be decrypted by the related private key. Public and private keys are large prime numbers that are mathematically related to each other but not expressed in writing the same.

  2. The two use cases for public key cryptography is cryptocurrencies and digital signatures.

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#3801
  1. Public and private keys are essential tools in encryption. They offer enhanced security against hacking on public networks when 2 parties wish to transact.
  2. Public keys, which are derived from private keys are used to encrypt a message to the author of said public key. His private key is then used to interpret the message. A public key can be used in digital signatures. The recipient of a transaction involving a digital signature can use the sender’s public key to verify the corresponding private key matches.
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#3802

  1. A public key is a shareable address generated/defined by adding a unique/secret private key into a formula. Doing so enables you to receive mail at a public and locked location that can only be accessed/viewed by knowing the private key while simultaneously verifying the source of the mail sent to you.

  2. Encryption and Digital Signatures.

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#3803

  1. private key is generated by the receiver of data, and is used to generate public key in which can be used to encrypt data to be sent by the sender of data. Private key is also used to generate digital signature by the sender, in which can be verified by the receiver by using the sender’s public key.

  2. encryption and digital signature

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