Homework on Public and Private Keys - Questions

  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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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 “double-spend”.

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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 doesn’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 can’t just take your truth (private keys) and go and PROVE it to someone else.

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  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. There’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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  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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  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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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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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.

  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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  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 someone’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 sender’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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  1. The PRIVATE KEY is a key generated by your pc from which a public key can be derived via a formula mathematically making the 2 keys relevant to one another.

Private key is exclusive to the owner unless it is stolen from/lost by the owner.
Private keys act as Digital John Hancocks, fingerprint, rubber stamp, wax seal, etc
Private keys are decrypters of messages encrypted using the public key derived from the particular private key.
Private key also facilitates identification verification of anything sent.
Private key leads to Public key
Public key CANNOT lead to the Private key.
Public keys lead to a private box which only the private key can open.
Public keys are available for anyone or to those whom it has been made available to see .
Public keys allow anyone with access to it, which is everyone, to encrypt a message for purposes of discretion.

Encryption
Digital Signatures

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  • A public key is generated from your private key. Others can see your public key and send money there (for example), but only you can access with your private key. Private key decrypts the encrypted message.
    1. encryption and 2. digital signatures
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  1. The public/private key works by the user having a unique private key that decodes a corresponding public key. The public key is available to the public to encrypt a message which can only be decrypted by the private key. Two users could exchange encrypted messages by using each others public keys.
  2. The first case is data encryption where the sender encrypts data using someones public key and sends it to them to decrypt with their private key.
    The second case is using public/private keys to verify the identity of the data sender. As a sender you can include your private key in a message to be cross referenced with your public key by the receiver.
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  1. Public & Private keys leverage the utility of hash functions by providing users a (private) key to access information and a (public) key to receive information on an open network. This way the information is secure and private on an open network.

  2. Public key cryptography can be used to securely send and receive information on an open network and in case of bitcoin, it allows people to keep their monetary value secure on an open network during transactions and because of private keys it also allows people to keep their monetary value in their own possession instead of in a bank.

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  • The private key is a random number from which a public key is derived by a one-way cryptographic function. The public key can be shared every where because it cannot be used to deduce the private key.
  • Digital signatures and encryption.
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1)Private key is a secret that no one will know unless it is leaked to the community. Public key is a key that is visible for everyone to see.
2)1st use cases is for encryption.It is where the use of private and public key to decrypt a message. 2nd use case is digital signatures. When sending a message, the sender will use its private key to sign the message and the receiver can use the sender’s public key to verify.

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1 Describe the concept of public and private key with your own words.
A private key is your unique digital signature whereas the public key, which is generated from the private key, is your public address

2 What 2 use-cases can public key cryptography be used for?
Verifiable digital signature
Encryption

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Homework on Public and Private Keys - Questions

  1. Describe the concept of public and private key with your own words.
  • Your public key is generated by your private key and can be used publicly to link back to your private key.
  1. What 2 use-cases can public key cryptography be used for?
  • 2 use-cases for public keys are for encrypting and for use as digital signatures.
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  1. The private key signs transactions and holds the crypto. The public key is generated from the private key to encrypt it so people cannot see the private key. The public key can be seen by anyone and can receive transaction on behalf of the private key.

  2. encryption: Hiding the message being sent so others cannot see it
    Digital signature: a way to identify that its you

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  1. One analogy of public and private keys in cryptography can be compared to a physical home address that anybody can look up and find but the key to unlock that home is held by the property owner and only that person. If the private “key” was compromised your property is also compromised. You can not derive the private key from the public key just as you can not feasibly reconstruct a physical key to unlock the physical home by utilizing the physical home address.

  2. Two use cases of public key cryptography are for Encryption and digital signatures.

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