Homework on Public and Private Keys - Questions

Blockchain and Bitcoin 101
#1732
  1. Describe the concept of public and private key with your own words.

Public key is like banking account or your name that you can share to others, but private key is like your password that you need to keep it secret otherwise you may lose your money and your identity. In crypto, public key is generated by private key

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

Encryption and digital signature

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#1733

Public key generated by private key (one way function). Public key is public and private key must be kept safe and secret.

Sending BTC or sending a message and signing

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#1734

Thanks for the correction!

#1735

  1. A private key is a randomly generated value, from which a public key is derived from. The public key can be shared with others (public), where a private key should be kept private.

  2. Public keys can be used to encrypt data, and can be unlocked or viewed with a private key. A private key can also be used to sign something as a form of verification.

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#1736

  1. Private keys are numbers created randomly. With a private key, a public key can be generated. The public key does not provide the identity of or access to the private key, however anything encrypted by the public key can only be decrypted by the private key.

  2. Public key cryptography can be used for encrypted messaging and to provide a digital signature.

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#1737

Homework on Public and Private Keys - Questions

  1. Describe the concept of public and private key with your own words.
    Private key produces public key, but not the other way around. Private is only for you to keep in secrecy and your public key is shown in public. You can sign a message or transaction with your private key and other people can use your public key check if the message really belongs to you or not.
  2. What 2 use-cases can public key cryptography be used for?
    Encryption and digital signatures. Encryption make sure the information secret and only the trusted party can unlock the secret with public key. Digital signature allows you to sign messages and everyone assuredly knows these signatures belong to you as the private key holder.
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#1738

  1. A private key is a (very) large random number generated by your computer, which you should keep safe and secret. The public key is a large number derived from the private key and can be shared with the public. While the public key is derived from the private key, there is no way to derive the private key from the public key - it only goes in one direction.

  2. Two use cases that public key cryptography can be used for are:

  • Encryption
    If you need to send a private message to someone, you can encrypt the message using the other personā€™s public key and they can then decrypt the message using their private key. This use case is not used very much in cryptocurrencies.

  • Digital Signatures
    If you want to send a message to someone and that person wants to verify that the message actually came from you, you can sign the message with a digital signature derived from your private key. The person receiving the message can then mathematically compare the signature with your public key and verify that the signature was was derived from the private key that generated your public key as well as the digital signature, meaning it was actually you who sent the message. In bitcoin, this is how transactions are sent - you sign each transaction with your digital signature so everybody can see it was actually your transaction.

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#1739

[quote=ā€œivan, post:1, topic:8431, full:trueā€]
Homework on Public and Private Keys - Questions

  1. Describe the concept of public and private key with your own words.
    A public key is generated by a private key to send a secret transmission from point A to point B. The public key can be seen by anyone on the network. The private key is kept secret by the owner. It is used to validate the senderā€™s authenticity and ownership. The public key is more like a verifiable address with no access to the private source.

  2. What 2 use-cases can public key cryptography be used for?
    The public key can be used for encryption to send messages or funds. The public key can also be used to identify the sender and ensure integrity of the message. This is called a digital signature. Anyone can see the public key. It is impossible to acquire the private key from the public key.

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#1740
  • Describe the concept of public and private key with your own words.
  • Private key is a unique number which is used to validate authenticity of receipt to a sender, and nobody must know it than ourselves. This private key can generate a public key o a blockchain address which is intended to be public, everybody may know it.
  • What 2 use-cases can public key cryptography be used for?
  • Encryption
  • Digital signature
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#1741
  1. private key is a randomly created number. From that number the public key is derived. it is impossible to derive the private key from the public key
  2. encryption and digital signature
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#1742

  1. A private key is used as digital signature, it can only be used by the owner or whoever holds that specific key. A public key derives from the private key and it is used to send or receive data. Anyone can see a public key.

  2. use cases: Encryption and Digital Signatures

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#1743

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

Answer: A private key is a unique identifier that can be used to decrypt messages or wallets so you can read them. A public key can be generated from a private key so that anyone can verify that a transaction has taken place on the public blockchain.

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

Answer: Encrypting messages so they can be sent securely and digital signatures to enable the exchange of value (i.e. cryptocurrency) on the blockchain without the ability to ā€œdouble-spendā€.

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#1744

Describe the concept of public and private key with your own words.
The public and private key cryptography is in some ways similar to that of hash functions in that it should be practically impossible to reverse engineer the public key that is derived from the private key. The difference from a regular hash function is that you can prove to someone that you know the private key without ever needing to share it and they will be able to verify that you are telling the truth.

My understanding of a public and private key cryptography in comparison to hash functions that doesnā€™t have the same characteristics but a few similarities. Is that you can say that it would be like you are able to prove to someone that you know the input to a hash function in relation to a specific output without ever needing to reveal the actual input to the person.

What 2 use-cases can public key cryptography be used for?
The two main use cases they can be used for is encryption and digital signatures. The encryption part is done through a creation of a random private key and derive a unique public key, then share your public key so that people can encrypt a message with it and only you or some other owner of the specific private key can decrypt the message. The private key is never in the need to be shared anywhere and the owner can still prove he is the owner of it and decrypt from the public key.

The other use case is important for Bitcoin and other cryptocurrencies in that of digital signature. Here we are not that concerned to hide what we send to a specific owner of a private key but instead PROVE that we sent a message and are the owner of a private key. We are using our private keys together with the message to create a digital signature that the other person can verify with the public key and the digital signature. Still the private key is never needing to be shared, thus we are solving the trustless process without needing to share any critical information.

This is at the core of the blockchain revolution in my understanding for the trustless system to work, to PROVE to someone that you are telling truth (owning bitcoins) but without showing the actual truth (private keys connected to Bitcoins) so that they canā€™t just take your truth (private keys) and go and PROVE it to someone else.

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#1745

  1. The concept of public and private key.
    Private keys are randomly generated by your computer and should be kept secret for security. A public key is generated by a private key and can be shared with the public for the transmission of messages. Only the person with the private key can decrypt the messages received via their public key. Thereā€™s no way a public key can be traced back to the private key.

  2. The 2 Use-cases for a public key cryptography are encryptions and digital signatures.

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#1746

  1. Public key is generates by the unique private key that allows everyone to see and use to receive funds. Private key is your identity that are generate by the wallet and it can decrypt the information with the use of public key.

  2. The two use cases are Encryption and digital signature.

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#1747
  1. The concept of private and public describes how messages and transactions can be sent on a public network while maintaining security between the participants of the message or transaction and any third party viewers. Any third party viewers of the message or transaction will only be able to see its public key, which is derived from a private key, which is only visible to the participants of the message or transaction.
  2. Public key cryptography can be used, in practice, with encryption or digital signatures. With encryption, the receiver of a message will be given a private key, which is a random number, and this then creates a public key, which will be visible to the public. Digital signatures on the other hand will give the sender of the message a private key, which also has a public key derived from it. Depending on which method is used, the private key creates a signature on the message, that can be referenced with the public key, to verify who is sending or receiving the message. But either way, any third party viewership can only reference the public key.
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#1748

Actually digital signatures are used so others can verify that you were the one that wrote the message. It is in a way the opposite of encryption. You use your private key to sign a message and others verify the message that it was indeed you who wrote it using your public key :slight_smile:

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#1749

Thanks, that makes sense. So with digital signatures, third parties will reference the signature and compare that to the public key. But with encryption, third parties only have the public key to reference. Got it.

#1750
  1. Public key generated message that anyone can see but private key is only for me to see. If someone send me a message I can read it only if I have a private key from sender.
  2. First use case is encryption and second is digital signature.
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#1751

  1. A private key is a randomly generated large number known only by the owner, while a public key is generated from the private key and known by all the network. If a message is encrypted with someoneā€™s public key, then the message can be decrypted with the private key belongs to the public key used for encryption. This is the encryption function (a message can be secured in this way). Also, a message can be encrypted with the senderā€™s private key, in this case with the public key belongs to the private key used for the encryption, the receiver can validate if the message came from the owner of the private key (digital signature).

  2. a. Enryption b. Digital signature

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