Homework on Public and Private Keys - Questions

[Alko89]

@Eva

Encryption of messages where public view of messages is blocked by applying a formula to the message so the message output is representative characters of the real message rather than an easy-to-read message. The message is digitally signed by the private key of the sender and the receiver uses the sender’s public key together with the digital signature to identify the sender and decrypt the message.

Encryption is when someone encrypts the message with the public key where only the owner of the private key can decrypt it. What you are describing is a digital signature.

[funkpowerrocket]

• Describe the concept of public and private key with your own words.
  A private key is designed to only be known by the owner, this is your digital signature for transactions and allows the owner to encrypt outbound messages. If you own a private key it is possible to setup multiple public keys that act as an alias to your private key without revealing your private key details. Public keys can be recovered if you have access to your private key but not the other way round

A private key

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

Digital signatures and encryption

[Eva]

I do remember Ivan saying that now that you mention it… Lol.

I remember now I thought that was interesting as if you didn’t really know somebody, but you had their public key, you could send them a secret message… Pretty cool… Lol

[jott]

1. The public key is a string of numbers and/or letters which is derived from the randomly generated private key. The private key in crypto is used for signing transactions. So everyone who has the public key can verify that the transaction was made by the owner of the private key.

2. It can be used to encrypt or to sign messages / transactions.

[DJM]

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

Private key is a very long random number, public key is derived from the private key through a mathematical formula. The mathematical process is one directional. The private key cannot be derived from the public key.

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

• Encryption – public key used to encrypt a message that can only be de-crypted with the paired private key (sender uses recipients public key to encrypt the message). NOT really used in cryptocurrency
• Digital signatures – sender of message uses their private key to mathematically generate a signature on the message. The recipient can use a mathematical formula to compare the signature to the senders public key in order to verify that the sender sent it. This how Bitcoin is sent. Any legit public and private key pair is a legit Bitcoin address. Bitcoin address is generated from your public key.

[Darnell_Calhoun]

1. A public key generated from a private key. The private key is generated by a computers. Both keys are unique and are never duplicated. Each individual person has both a unique public and private key.

2. Two use cases that a public cryptography is privacy and verification. With the unique private key generated which allows a person access to their account. The public key is generated so that the acccount can receive information without access to reterive information from within. Verification with a public key (or digital signature for improved level of security) allows the reveiver or giver of information to verify that the giver or receiver is the right person.

[RagnarAces]

1.The private key is what unlocks a virtual identity and it’s what gives access to a Bitcoin address. The public key is derived from the private key and a one-way path.

2. Encryption and Digital signatures

[Mynor]

1. When creating a wallet on a blockchain, you are issued a private key at random, which automatically matches a public key to your private address. From there, using you public address you are able to safely transact in the network.

2. Sending secured encrypted data and sending value.

[Rob03]

1. A private key gives the user complete access to the account, similar to your password for internet banking except even stronger. A public key is like your account name where people can send money to your unique address without having any ability to touch the funds. Your public key is generated from your private key which allows for you to tell anyone your public key without compromising the account security.
2. Public keys can be used to receive funds. A public key can also be used to verify a signature is from a certain source and confirm that has not been tampered with.

[Alko89]

@funkpowerrocket

If you own a private key it is possible to setup multiple public keys

A private key can only have one corresponding public key, the way you can have multiple private keys through one master private key is to generate more private keys in a hierarchical fashion, this is how HD (hierarchical deterministic) wallets work. The concept is described in bip32

[daninvest]

1. When you first get your wallet, the computer generates automatically the private key. This private key will be necessary both to receive and send (signing transactions) cryptocurrencies. It is important that this private key won´t be known by anyone, otherwise they could steal your coins.
   The public key is generated by the private key, and it is way shorther. This public key, that encrypts the message, is shared with others.

2. It can be used to encrypt a message and to shared infomation with others

[Alko89]

@Rob03

Public keys can be used to receive funds. A public key can also be used to verify a signature is from a certain source and confirm that has not been tampered with.

Both of these are digital signatures, public key cryptography can also be used for encryption.

[Phlpp]

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

Every participant has a private key and a public key. The private key is a large number, which has to keep secretly. The public key is created from private key, but there is no possibility to get back to the private key. So if a message is send to a public key address of someone, the public key encrypts the message totally. Only the owner of the private key, which one is connected with this public key, can decrypt the message.

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

Public Key Cryptography can be used for encryption and digital signatures.

[dapp.coding]

Homework on Public and Private Keys - Questions

1. Describe the concept of public and private key with your own words.
   Easy peasy, look at it this way :
   The private key is a way to sign a transaction (special secret pen)
   
   
   
   Illustration source here

The public key is a way to verify a transaction (special public shared torch).

You keep the pen to yourself and it’s a random pen you generated.
You share the public torch but nobody can use it without the signed message.

2. What 2 use-cases can public key cryptography be used for?
   Cryptography can be used to
   A. Encryption of messages
   
   Source here

But also,
B. for digital signatures used mainly in the bitcoin network.

More about encryption here.

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[Jari_Landman]

1. The public and private keys are linked with each other in such a way, that you can use the public key to interact with the world, While protecting your address with a private key. This private key is very secret to the world and must be known only by the owner.
2. For encryption, where the public key is used to send an encrypted message to and the private key is used to solve the message. For Digital Signatures, where the private key is used to sign a message made through the public key.

[Jiaying]

This explains the math.

[Jiaying]

1. Private key is a random number that is generated by my computer. We use a one-way cryptographic function to generate a public key, which can be open to public. Bitcoin adds one more layer of security and generates bitcoin address.
2. Encyption and Digital Signatures

[Alko89]

@Jiaying

Bitcoin adds one more layer of security and generates bitcoin address.

Hashing public keys to addresses is not really a security measure, its main reason is to save on storage. The public key is 65 bytes long in comparison to a hash that is 20 bytes long

[funkpowerrocket]

Awesome thank you for clarifying will get reading on Bip32!

[Arisgo9]

1. Public Key is the generated hash everybody can see and it is generated from the Private Key, your personal key that ONLY you know/can see IF you have the credentials.

2. Encrypting messaged and for Digital signatures.