Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#203
  1. Describe the concept of public and private key with your own words.
    a private key is a large random number that is kept secret and only to owner should know. Mathematically derived from the private key, a public key can be generated and given to public use. There is no way to find the private key of a given public key.
    In case of BC: Others can send you BC to your public key (or the generated adress from the public key) and you’ll have access to them as long as you know the private key that generated the public key.
    The private key is used by you if you send the BC, to sign the transaction.
  2. What 2 use-cases can public key cryptography be used for?
    Encryption and digital signature
#204
  1. A computer can generate a random number as your private key. From there with a one way cryptographic function you generate your public key, which you could share. One more layer would be from there to generate your bitcoin address. You use your private key to sign a transaction.
  2. The two use cases of public key cryptography are Encryption and Digital Signatures.
#205

  1. Private and Public key are a pair two mathematically related cryptographic elements.
    Together they work to secure and authenticate data/messages.
    To decrypt the data/message on a public key you need to use its corresponding private key. The Public key is derived from private key, its public and open to everyone. The Private key should only be known by its owner, and its what grants ownership of funds on a given address.

  2. Encryption and Digital Signature

#206

  1. Public and private keys are used to govern security over a public network also known as an open channel. The keys can be used to lock and unlock messages and/or files, or they can be used to “sign” them. The author of a key pair establishes a private key with a large random number and a public key is generated from that. Others can encrypt with the public key, and the key holder can decrypt with the private key. The key holder can also create a signature with the private key, and anyone can verify it with the public key.

  2. Public key cryptography can be used to encrypt documents and to verify the signature of a private key holder.

#207

  1. Public key is a number generated from a private key, which is also a randomly generated number. The public key can be used to encrypt messages that can only be decrypted by the holder of the private key. Further more private keys can be used to sign messages and the public key can be used to verify the authenticity of the message. As the name implies public keys are public and private keys should be kept secret.

  2. Public key cryptography can be used to encrypt messages and keep them secret from people that do not have access to the private key. Also a private key can be used to sign messages, the signature can be verified using the public key.

#208
  1. Describe the concept of public and private key with your own words.
  • Public Key is used to encrypt a message when using a non-secure network, it is for everyone to see. The Private Key is a number randomly generated by the receiver’s computer and is used to decrypt the message sent, it is only known by the receiver.
    It is impossible to know the Private key paired to the Public Key.
  1. What 2 use-cases can public key cryptography be used for?
  • a) Encryption of messages
    b) Digital Signature: allow us to verify who sent a particular message signed with the private key of the sender, the receiver will verify the message using the know public key of the sender. (Example: verify bitcoin’s transactions)
#209

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

The private key is a randomly create number which is your digital signature. the public key is derived from the private key to be used in a transaction.

eg: Alice wants to send a message to bob. Alice creates a private key with which she signs the message to bob. Bob can take Alice’s Private key ( Digital Signature) and her public Key to verify the transaction.

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

Sending Bitcoin with the Private key and receiving Bitcoin to the Public Address.

The ability to send encrypted messages or Value transfer without anyone else being able to see the message. The transaction can be seen on the block explorer but not the message.

#210

  1. A private key is a randomly generated password from a crypto wallet that you should never give to anyone to use or they will have access to your wallet. A public key is generated from a private key in order to use as a transaction address to send or receive funds or information from a crypto wallet, this can be shared with public.

  2. Encryption and Digital signature to send and receive messages/funds.

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#211
  1. Public and private keys are random numbers that are used to ensure a stable security within a blockchain network.
  2. Public key cryptography is used for encryption and digital signatures.
#212
  1. Public key can be seen by all. Private for my eyes only.
  2. Encrypted Messages as well as signatures
#213
  1. A computer generates a large random number thus creating a private key. Then from the private key a number is derived (mathematically) producing the public key.
    2.Two use-cases:
    a)Encryption ⇒ If we want to send a message to person A we use public key (A) and we encrypt the information in the message. Then A uses his/her private key (A) to decrypt the content we sent.
    b)Digital Signatures ⇒ This is to verify the sender. Sender B creates a signature with his/her private key. Person C, using the public key of B, verifies the signature.
#214

  1. Public key is to be shared to the world and is used to encrypt messages. Private key is the key that you hide from the homosapiens, that you do not share and able you to decrypt and sign digitally.

  2. Encryption & Digital signature

#215

  1. If somone wants to send another person a private message they encript the message so only the private key can read it. The puplic key can be read by everyone.

  2. It can be used to encript a message or it can be used to identify a message.

#216

  1. Private keys are a collection of randomly generated numbers; public keys are derived from private keys. These keys allow for encrypted and private communication between agents, where anyone can message someone’s public address and be sure only its private key can see the messages contents.

  2. Encryption and digital signatures (so you can know people are who they say they are).

#217
  1. The wallet holds your private key. The private key should never be shared with anyone. The private key generates the public key, also your address. The public key can be used to receive and send Bitcoin.

2.The public key is used for sending Bitcoin and secure email

#218

  1. A private key is a random number generated by a computer. A public key is generated by a hash function that takes the private key as an input.

    1. Having encrypted conversations in public. 2) Digital signatures, so that you can tell who sent a message.
#219

A private key is a random set of characters that your computer generates in order to digitally sign your transactions on a digital ledger and to create your crypto address. The private key is the decoder of such transactions because your Public key is generated using the original private key characters. This randomly generated string has near zero chance that it will collide or match with someone else’s private key. (this key is for your eyes only!)

The public key on the other hand is generated using your private key and is shared with everyone on the network. This key allows you to encrypt your data and identify yourself to the network while keeping the integrity of the system in check.

  1. Public Key Cryptography allows for digital signatures, network integrity and to identify yourself.
#220

  1. Describe the concept of public and private key with your own words.
    A private key will be generated by your computer and will be a large number which will be completely private and not able to be viewed by anyone else. This private key then generates a public key which is visible by anyone. The public key can be used to send a message to another person which has been encrypted with their private key. This can then only be read by the intended recipient as they would need their own private key to read. You can never work out a private key based on the public key.

  2. What 2 use-cases can public key cryptography be used for?
    One use case is the use of digital signatures which is a key feature for Bitcoin transactions. It could also be used to encrypt messages that are being sent on an open network for security. Then only the recipient would be able to read the message.

#221

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

    Private and Public keys are used in cryptography to encrypt and decrypt messages. A Private key is random number generated and a public key is then hashed from the Private key output. If a person wants to send a message over an unsecured network they can encrypt the message to their public key then send the message to the public key published by the receiver and hashed from the receiver’s Private key, the receiver then un-encrypts the message using their Private Key. The encrypted message can only be decrypted by the recipient who has the private key that the Public key was hashed from.

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

    Encryption and Digital signature are two use cases.

#222
  1. Describe the concept of public and private key with your own words.

First off all without the private key you can’t do anything. When you set up a wallet you generate a private key. You keep this save and never give to anybody, that’s why it is called private key. This number is so to say your personal digital signature and the proof that this wallet or adress is yours.
When you have your digital signature- private key, you can generat a public key which is to give and share to everybody. When somebody has your Public key the only thing he can do is send you an encrypted message or cryptocurrencies.
It is almost 100% impossible to find your private key if he has your public key. An extra safety layer in some blockchains is that after you generated the public key you generate one more number that is actually the adress you can give to everybody who wants to sent you anything digital.

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

Public Key cryptography is to share with others who want to send you something encrypted or to generate a second layer of safety adress “key” wich is then actually your official public key. I think a good example exept Bitcoin Blockchain is ustopable domains. You get an adress like an email which you give to everybody to send you anything and before that you have generated a public key and before that your private key in a cryptoblockchainwallet. So three layers of security that no one can brake and actually hack your private key.