Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#607

1/ publick key is for everyone to see and encrypts the information . Privat key is only for me and decrypts the information
2/ encryption and digital signatures

1 Like
#608
  1. Private keys are the access to your wallet / account and should be kept, well…, private!!
    Public keys are the visible part of your private key, (an identifier).
  2. Public keys can sign transactions and encrypt messages.
#609

  1. A private key is basically a long random number from which is derived a public key. If you gain access to someones private key one can figure out their public key, but with a public key one cannot calculate what the private key was that was used to generate the public key. It is also practically impossible to guess a private key. They are so long that the number of possible permutations you would have to guess through is inconceivable. One would have to be guessing longer than the age of the universe in order to come across a previously used private key. The relation of the private key to public key is such that anyone can use the receivers public key to encrypt a message that will then only be able to be decrypted by the receivers private key. For this reason, in order to maintain the security of the message, one must keep ones private key secret.

  2. The two use cases of public key cryptography are

a) - Cryptography, that is, sending a message securely on an open channel. One uses the receivers public key to encrypt ones message. Only the receivers private key can decrypt it.

b) - Digital signatures, or the verification that a message comes from a particular sender. In this scenario, a sender or signer “signs” a message, file, or any data using their private key. The recipient or verifier uses the signer’s public key to verify that the signature could only have been created by the holder of the private key that was used to generate the given public key.

1 Like
#610

  1. Public and private keys are computer generated random numbers to be used by other computers for identity and security measures. The public key can be seen by anyone but the private key should only be seen by the person its intended for. Public keys are generated from private keys to grant others the ability to take action on your behalf. The private key is to secure that action or value transfer from others.

  2. Encryption for sending and receiving information, i.e. messages and digital signatures for sending and receiving transactions relating to value and or security.

#611

a public key and a private key is data connected together and used to encrypt data sent between parties

public-key cryptography can be used for sending data securely that is encrypted so no one can read them

1 Like
#612

A public key is open to see for everyone on the network where as a private key is only viewable by the owner of the wallet. (unless you are careless and someone gains access to your private key)

Encryption and Digital Signatures are the 2 use cases for cryptography. This provides security when sending value so you can know who sent and who received said value

1 Like
#613

The one way hash function creates the public key from the private key. The private key is unique because it is a random number from a practically infinite bunch of possible numbers.
Value or data transactions and digital signatures

1 Like
#614

  1. Describe the concept of public and private key with your own words.
    A public key and private key are used to sign and verify. Whereas public keys are out for the open and can private keys are secret.

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

1 Like
#615

  1. The public and private keys are key (no pun intended) for encryption. The private key is a randomly generated number by a computer that in turn is used to generate the public key. The private key is kept secret by the user and only the public key is observable by the public. Encrypted messages by public keys are only able to be decrypted by the use of the private key, thus providing security and privacy to the communicating parties.

  2. 2 use-cases for public key cryptography are encryption and digital signatures. As mentioned in A1, encrypted messages by public keys are only decrypted by use of the private key. Digital signatures however are messages that are signed by the private key and through use of the public key does one confirm the validity of the message that it came from the private key.

1 Like
#616
  1. Public key is the code you show everyone in order for them to send encrypted messages and transactions to you, but they cannot use your private key to take anything from your account or read your sent messages. The private key generates the public key and is used to sign secret messages and transactions. You must keep the private key safe.
  2. Encryption and data signatures
1 Like
#617

1: The public key is shared and is used to encrypt transmissions. The private key is kept secret and is used to decrypt messages.

2: Email and cryptocurrency transactions.

#618

  1. A public key is a random combination of numbers (like an address). From this string of numbers a function is calculated to derive a new string of numbers called a private key. Public keys are available for anyone to see, whereas private keys are kept secret and can only be seen by the idividual who generated them. You derive the public key from the private key but cannot derive the private key from the public key making this function pre-image resistant.

  2. The two use cases for public-private key cryptography are:

Encryption - Whereby a sender can use the public key of the receiver to encrypt a message sent across a public network, which can only be decrypted by the private key which is linked to that public key. Meaning only the reciever would be able to view the message. This was & is still used by dark web markets such as silk road for communication between buyers and sellers.

Digital Signatures - Whereby the public key generated by the private key can also generate an address on the network. when a transaction or exchange of a value occurs, the person sending the value will send it to the public address and use their own private key to sign the transaction and confirm to the network that the transaction was made by that address (or by them). Without this signature a transaction cannot be made meaning anyone who has access to a private key has access to any values/data/cryptocurrency that is associated with that particular private key.

1 Like
#619

  1. A private key allows you to sign transactions and to generate public keys which can be used to receive transactions publicly.

  2. Two use-cases that public key cryptography can be used for are encryption and digital signatures.

1 Like
#620
  1. Describe the concept of public and private key with your own words.
    • A private key is a randomly generated number. A public key can be generated from a private key using a one-way function.
    • Private keys can be used to create digital signatures that can be verified against the public key that was generated from that private key.
  2. What 2 use-cases can public key cryptography be used for?
    • Encryption
    • Digital Signatures → Identification and Integrity
1 Like
#621

  1. The public key is used by others to encrypt info that only you can decrypt with the private key. You can also use the private key to sign things with a unique digital finger print tied to you.

  2. public key cryptography can be used for encrypting a transaction and sending it to someone. The other use would be just to digitally sign something

1 Like
#622

  1. Describe the concept of public and private key with your own words: The public key is a random number generated by your computer while the private key is used to “open” the public key. In encryption, the private key generates the public key. In the case of digital signatures, the private key is used to sign the transaction. Everyone can see the public key while the private key is kept secret.

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

1 Like
#623

You need to sign a message to someone else public key using your private key. The receiver can verify the message with the digital signature that it is coming from you based on your public key. That’s the beauty of it. You don’t need to reveil your private key to proof your identity

#625

  1. A private key is a random number that is generated and used to derive a public key. This is used to encrypt data. The public key can be derived from a private key but you cannot get the private key from a public key.

  2. Public keys can be used for encryption and digital signatures.

#626

But not just any hash function. It uses ECDSA Elliptic curve cryptography

https://medium.com/coinmonks/private-and-public-key-cryptography-explained-simply-4c374d371736

#627

  • Describe the concept of public and private key with your own words.
    The private key is only known by the owner. The private key will generate a public key. This one is ‘shareable’. Both the keys can verify data. For example who sent the message (digital signature) and it can be used to encrypt data.

  • What 2 use-cases can public key cryptography be used for?
    First method is encryption (not used by bitcoin)
    Second method is digital signatures (used by bitcoin)