Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#2701

  1. A private key is a random number generated and is used in conjunction with a public key through encryption to send or receive a message privately in a public arena. Your public key is generated from your private key through a one way function and is linked to the private key but in no way can the public key be used to derive the private key. A sender can use the receivers public key to encrypt a message and the receiver can decrypt that message using their own private key. The sender can also digitally sign a message or transaction using their private key and the receiver can verify that signature using the senderā€™s public key.

  2. Encryption and Digital Signatures

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#2702

1.my private key is a secret code known only to me
my public key is known to everyone i send it to
2.i can use a public key to recieve bitcoin
or sign some kind of digital file like a documet or email

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#2703

  1. When creating a digital signature you are getting a set of keys. One private that only you see and another, generated from the private key, a public key for all others to see. You can use your private key to sign something, not visible to others, however the public key will be visible to others so they can confirm that it is definitely from you

  2. Public Key Cryptography can be used for Encryption and Digital Signatures

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#2704

1- a public key is a unique alphanumerical string that is generated by the private key issued to a piece of data by the computer through a hash function. the private key could then be used to decipher any date encrypted to the public key issued by the specified private key in relation to the signature provided.
2-for generating digital signatures, and encryption

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#2705

  1. The private key is a random number that generates a public key that is another random number and together they are used to encrypt and decrypt messages.

  2. Case 1: The public key is shared publicly and then someone can send encrypted information and only the person with the private key that generates that public key can read the message. Which guarantees a very safe way to send information to a certain person.
    Case 2: Using the private key, a digital signature can be generated that will confirm that this particular person sent the message

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#2706

The public key is not random. You start with a random private key and the public key is ā€˜calculatedā€™ from it using eleptic curve cryptography

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#2707
  1. Princess and Chest story: asymmetric encryption. Princess locks with with her pvK. Prince receives chest but its locked. Then he puts his pvK on it and sends it back. The Princess now opens with her pvK and the Chest goes back to the Prince. Finally he can open it and is 100% sure its untouched.
  2. Encrypting data & digital signments
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#2708

Homework on Public and Private Keys - Questions

  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?

1- The private key is created by the User consisting in a long number, from which, through a specific formula the Public Key is created. This is a One Way Function, therefore it is impossible to go from the Public Key to the Private Key.

2- The first use case is encryption, in which a message is encrypted and con only be read if the receptor has the public Key of the sender.

The second use case is to generate unique digital signatures. The private Key generates the Public Key that creates de Digital signature, the receptor can verify that the signature comes from The Private Key that generated the Public Key.

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#2709
  1. private key for encryption and decrypting - public for sharing

2.The public key is the address you share so other people can send you Bitcoin to that address that you digitally signed.

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#2710

Homework Assignment : Public and Private Keys (Answers)

  1. Client created cryptography.
  2. 2 uses cases:
    a. Sending encrypted messages via public key.
    b. Digital signatures
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#2711
  1. Describe the concept of public and private key with your own words.
    -the private key is a randomly generated number that must be protected, because with it you will sign your transactions to verify it was you who spent that bitcoin. the public key is generated from the private key and can be displayed for the whole world to see, because you will receive funds through your public key. but even though people know your public key they canā€™t figure out your private key from it because of the unidirectionality of the hash algorithm.
  2. What 2 use-cases can public key cryptography be used for?
    -for encryption and digital signatures
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#2712
  1. The public key is a string of numbers and letters generated by the private key. Your public key is for sharing your private key is for yourself. With a public key, messages can be encrypted and sent to a private key where they can be opened.
  2. You can use a public key for encryption and digital signatures
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#2713
  1. A pair of private and public keys are apart of a cryptographic system that are primarily used to encrypt and identify data to its correct owner and recipient. A private key is a randomly generated number that can be compared to a password. A public key is generated from the preceding private key and like the name applies, can be shared to others with no exposure to the private key. It is mathematically impossible to derive a private key from a public key.
  2. Public key cryptography is mainly used for privacy and digital signatures of data. Given a public key, one can encrypt data with said key so that only the party with access to the corresponding private key can decrypt and view the data. Additionally, one can sign data with a public key. All parties in possession of the data can verify that the data was indeed signed with the public key.
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#2714

  1. The public and private keys can be used to receive and send messages securely over the bitcoin network. They encrypt and decrypt messages.

  2. The Public key is derived from the private key that can be used to receive messages.
    It can also be used to encrypt a message to send to another address.

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#2715
  1. User creates a random private key and keeps it secret. From this key she creates a public key. The public key can be shared with anyone. Messages encrypted with the public key can only be read using the private key.
  2. Encrypting private messages & digital signatures.
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#2716
  1. Private Key is a big random number generated by a computer. From the Private Key the Public Key is hashed. You can alway calculate the Public Key hashing the Private Key but you cannot make this calculation backward to find the Private Key based on the Public Key.
    The Private Key is like the name already says yours and must kept secret. The pUblic Key you can share with the world.
  2. Encryption and digital signature.
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#2717
  1. Private keys are unique to a specific user and are private. These are used to generate public keys that can be used in transactions.
  2. Encryption and digital signatures
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#2718
  1. Computer generate private key, private key generate public key. Public key encrypt data, private key decrypts it.
    1. Public key encrypt data
    2. You can check signature with senderā€™s public key
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#2719

Public keys are derived using the elliptic curve function, not SHA256. :slight_smile:

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#2720

A private key is a big number generated by your computer. This one should not be shared with anyone. A public key is another big number generated from the private key, which is used publically to send and receive transactions. Basically other people can use your public key to make transactions with your private key(which is your wallet).

Public key cryptography can be used for secure messaging between two parties and secure payments.

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