Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#2559

1- computer generated set random numbers a private key creates a public key, public key can be shared,
it is to encrypt sensitive info and private key decrypts this info that was encrypted with the use of the public key. The private key can be used to sign, as a signature or fingerprint.
2- The 2 use-cases are encryption and digital signature/fingerprint. Digital signatures verify the message since private key derives the public key which creates address. Cryptography and using public and private keys solve security issues using the internet

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#2560
  • private key: computer generated number that is near impossible to guess
    -public key: a mathematically generated number that stems from the private key, that can be shared with anyone, without compromising the security and privacy of the private key
  • encryption
  • digital signatures
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#2561

1 - Private key is random number that is generated by my computer. We use an one-way cryptographic function to generate a public key which can be seen to public.

2 - Encryption and digital signatures.

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#2562

  1. Private keys are the seeds to generate public keys. Using private keys one can generate a public key but the private key can not be guessed from the public key, this is called asymmetric encryption.

  2. Cryptographic public keys can be used for two things:
    a) To encrypt messages so that only those with the correct private key can read them (Message encryption)
    b) To sign a message with a private key, so that it can be validated that the message was indeed signed by a given public address. (Identity Integrity)

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#2563

1.The private key is a very long number generated by your computer which is used to produce a public key. You can use the private key to generate the public key but you cannot use the public key to generate the private key. The public key is for the world to see and is for public use but is connected with the private key.
2. Public key cryptography is used for encryption and digital signatures. With encryption, one can encrypt a message using another’s public key and the receiver can read the message by using their private key. With digital signatures, a person can sign the transaction using their private key to verify the transaction.

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#2564

  1. A computer randomly generates a private key. Public key is derived from that private key. Message is then encrypted using the public key (available for everyone to see) but can only be decrypted and read using the private key.

  2. Public key cryptography can be used for encryption and in the case of Bitcoin - Digital signatures. Digital signatures are used to verify who sent the message.

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#2565

  1. Public and private key concept is a form of cryptography used to encrypt data and produce digital signature. Everyone can see ones public key but only the person who really needs to see the message/data has the private key and you need to have both to get access to the message/data. And to encrypt the data that one wants to send, one needs to use public key from the person they want to send that data to, and that public key is generated from that recipient private key.
    As for the digital signature, it is a cryptographic way to assure certain data comes from certain adrress. The signature comes from private key,but there is no way someone can get your private key simply from your public key.

  2. Digital signature and encryption

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#2566

Here’s my take on Pub/Priv Key after re-visiting this topic many times.

  1. PubKey is derived from PrivKey (256bit random number) using Elliptic Curve Cryptography.
  2. The reason a hash function is not used because we want to sign the transaction with the same Private Key, and then later let everyone verifies the signature with the PubKey. Hash function provide digital finger print (ensure tamper-proof) but no ability to verify.

Please share your thought on this @ivan @filip

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#2567

  1. When your private keys are generated you must be sure to keep them safe and secure, this will be used to decrypt messages as the recipient. Your public keys on the other hand are then used for transactions on the network, to either send or receive encrypted messages.

  2. Sending or receiving transactions or messages.

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#2568

  1. Private key is effectively a random large number which is generated and held by your wallet. The private key is what signs all your transactions and allows you to “access and spend your funds” in the blockchain. It must be kept private and known only to yourself at all times. In contrast, public key is also a number derived from your private key, but can be freely shared anywhere. The mathematical relationship between these 2 numbers is such that anyone can use the public key to encrypt a message, and only the private key can decrypt the message. Bitcoin has no accounts thus any legit public & private key pair is automatically a legit Bitcoin address. If you lose your private key, or if someone gets access to it, you will have lost your funds

  2. In normal computer science, you use public key cryptography for:
    a) Encryption: To add layer of security to a message (privacy)
    b) Digital Signatures : Identification and to verify the integrity

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#2569
  1. The concept can be descibed as a one way function, strating with the private Key which when generated will then generate the public Key, everyone can see the public key, but only you hold and see the private key and also the private key is never visible in the public key.Anything encrypted by the public key can only be seen or decrypted by the private key.
    .
    1. Encryption of messges or information 2. Digital Signature for sending funds or a message
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#2570

  1. Public and private keys are used to encrypt data and transfer it over unsecured or public means. A private key is known only by the person generating the pair, and the public key can be used by anyone to verify that some data was generated by the party who controls the public key.

  2. Data encryption and digital signatures.

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#2571
  1. Describe the concept of public and private key with your own words.
    The private key is randomly generated by a computer and the public key is derived from a private key.
  • An another words you can say that; * Your public key is your account number where you can access you wallet and * Your address is your account number too.
  1. What 2 use-cases can public-key cryptography be used for?
    You can use your public to receive encrypted messages, you can use it for receiving BTC. The public - key is visible to everyone as well. It is impossible to go from public to private, it is a one-way function.

Also as a digital signature.

*Basically you need your private key to access your wallet, so make sure not to reveal it to anyone.

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#2572
  1. Private key is kind unique code/signature that allow decrypt message, transactions encrypted by public key witch is generated based on that unique private key.
  2. (i) Encryption (ii) Digital Signature
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#2573

Q 1) Private key and public key have been around for some time and were original uses to encrypt messages sent on a computers on an open and unsecure network unsecure. The private key is a very long random number generated by a PC this is then mathematically used to generate public key. The private key now has a mathematical relationship with public key.
The public address key is unique personal address it can be on the Internet and show on any website. An encrypted message using the public key can now be sent another person who decrypt the message using the private key.

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#2574

You only described encryption. Do you know what the other use case may be? :wink:

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#2575

  1. Describe the concept of public and private key with your own words.
    Using Public Key Pairs to Ensure Both Security and Identity
    But the order of using the key pairs can flip to ensure the identity of the sender. If a sender uses a private key to encrypt a message, the recipient can use the sender’s public key to decrypt and read it.

  2. What 2 use-cases can public key cryptography be used for?
    Public key cryptography uses a pair of keys to encrypt and decrypt data to protect it against unauthorized access or use. Network users receive a public and private key pair from certification authorities. If other users want to encrypt data, they get the intended recipient’s public key from a public directory.

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#2576

You switched the two. You use the public key to encrypt a message, but you do use the private key to sign a message. :slight_smile:

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#2577

Homework on Public and Private Keys - Questions

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

The concept of public and private key is that end user one sends a message which generates an encrypted Public Key and signature which is provided to End User two, who in turn compares the Public Key and Signature using the Private Key to decrypt the message.

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

The two major use cases are Encryption and Digital signatures

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#2578

1.Private Key is a randomly generated string of numbers and letters allowing you to access your bitcoin.
A private key is mathematically related to your bitcoin wallet address but is impossible to reverse engineer.
Your public key is generated by your private key which then generates your wallet address in order to allow transactions with others.
2. Encryption and Digital Signature

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