Homework on Public and Private Keys - Questions

[Mikos]

1. A user’s computer generates a private key which he will keep secure and to himself.
   The public key is generated from the private key using a mathematical formula and is intended for
   the world to see. This system allows for information / data to be transferred securely.

2. • Encryption
   • Digital signature

[dbtex35]

1. Describe the concept of public and private key with your own words.
   Public key is what you give out to receive funds.
   Private Key is used as a signature when you send funds.
   Public Keys are used to encrypt information and Private keys are used to decrypt the information containing the Public keys

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

[Reid]

1. Your computer generates a large random number. This random number is your private key. Your computer uses this “private” key to create a new number and this new number is known as the "public’ key. This public key has a mathematical relationship to the private key that was used to create it, but the private key can not be reverse engineered out of the public key.

2. The two use cases of keys discussed here were: Encryption & Digital Signatures
   With encryption you create a private key > public key. You hide the private key and display the public key. The public key is used by someone else to encrypt a message that they are sending to you. Due to the mathematical relationship between your private key and the public key, only your private key can de-encrypt the message.
   with digital signature you create a private key > public key. You send a signature to a recipient and this signature contains you private key. This recipient can look at your computer and see the public key. They can use the private key you sent them to verify with the public key you have on display to validate that you were who sent the signature.

[Alko89]

@dbtex35

Private Key is used as a signature when you send funds.

@Reid

and this signature contains you private key

Private key is not used as a signature nor does it contain it, that would mean you exposed your private key and that would not be good. You use the private key to sign a message/transaction

[Vivek20]

1. Private and public keys are numbers. A public key can be derived from a private key but never the other way around. You can use the public key of the recipient to encrypt a message that can only be decrypted by the private key. Or you can sign a message with your private key which can then be validated with your public key.
2. The 2 use cases are encrypting messages and signing messages.

[gonzo]

1. Describe the concept of public and private key with your own words.
   It’s like having a lock and two keys. One is used to open the lock (Private) and the other one is used to close the lock (Public).

2. What 2 use-cases can public key cryptography be used for?
   Encrypting messages and Bitcoin transactions.

[Lurkur]

1. Public keys are generated from the private key. Only the private key can decrypt a message encrypted with the public key.
2. Encryption and digital signatures.

[Rob1]

@ivan

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. Public and private keys are keys needed to communicate on a public network where people not a part of the conversation don’t need to know what you are talking about. It allows people being spoken too to know who is speaking to them, through private key signature that sender sends with message.

2. Encryption and digital signatures.

[thoth]

1. Private keys are number codes assigned to prove the ownership of an item in the blockchain. Public keys are numbers/codes derived from the private/ownership key to identifying the owner of the item for public transactions without giving away the location and title to the item.
2. Real estate transactions and Insurance

[dennisw]

1. the private key is for your eyes only .its private
2. plubic key. is for everybody to send you data.{btc} and digital signature

[CC123]

1. Private key is a random number that should only be visible to the owner, public key is number derived from the private key that can be shared with others. Only the holder of the private key can unlock something encrypted with the public key
2. Signatures and encryption.

[dgbit]

1. Private key is random generated number that is unique (probability of collision is infinitesimal). Public key is a number derived from private key using an algorithm.

2. Public cryptography can be used for message encryption (like https protocol) so that only the recipient that knows the public key can read the message. The other use is digital signature, by which the receiver of the message can verify that a signature is valid given the public key that is associated to the private key that generated that public key.

[Alko89]

@thoth

Real estate transactions and Insurance

I think both of these would utilize digital signatures. You can also use public key cryptography for encryption.

[carolb]

• Describe the concept of public and private key with your own words.
  A) The private key is mine and mine alone. It’s a secrete. Access is allowed to all on the public key. Everyone can see it.
• What 2 use-cases can public key cryptography be used for?
  A) Signature and encryption.

[paddyc1]

1. The private key is randomly generated and is what gives you ownership of your wallet. The public key is derived from the private key and cannot be used to access the private key, it is a one way encryption.

2. Public key cryptography can be used to encrypt messages, and for digital signatures which verify the identity of the sender.

[conwayddd]

1. The private key is what allows you to verify your identity, and can be used to derive the public key. The public key cannot derive the private key.

2. Data encryption and identity verification.

[J_Door]

1. The Public Key is the result of hashing your Private Key.
2. Verification of authenticity and encryting messages.

[AlexaE]

1. A private key is a random number that is your digital signature & you can use to sign transactions. From there, you generate a public key which can be out in the open to everyone.

2. When sending someone crypto or any messages, you take the person’s public key and encrypt in into the massage, so that you can read it. But only you! Then you can verify that the message is really from the person you think it is, by having them sign their digital signature.

[tung]

1. Public Key cryptography is a type of asymmetric cryptography involve a pair PubKey-PrivKey.
   PrivKey is a large prime number that is used to generate the PubKey (through Eliptic Curve Cryptography), which is available for everyone to see.
   You give PubKey to the sender to encrypt the their message. They send the encrypted message and only you can decrypt with the associated PrivKey.

2. The first use case is Encrypt-Decrypt Message. The second use is Verify if the message is sent by rightful owner. This is done as followed:

1. Use PrivKey to sign a message => generate signature
2. Send the Signature and PubKey to prove ownership of associated PrivKey
3. Everyone can verify the Message is signed by PrivKey associated with such PubKey. But they can’t derive the PrivKey from Message and PubKey.
   This is how Transaction Verification done in Bitcoin Network

[Alko89]

@J_Door

The Public Key is the result of hashing your Private Key.

We don’t use hashes to generate public keys, for that the elliptic curve function is used.