Homework on Public and Private Keys - Questions

[Cryptojuice]

1. A private key is just a random number generated by your computer. It is for your eyes only and will be used for identification purposes. A public key is generated from the hash of the private key. The public key is used to encrypt data sent to you. The private key ensures that only you can read it.

2. Encryption and Digital Signatures

[Gemstar]

1. Private Key is a random number used for digital signature and should be kept secret and safe.
   Public Key is derived from Private Key and is the key you share with the public and used to send BTC or receive sender’s BTC. Anyone can use Public Key to encrypt (secret, sensitive) messages, which only Private Key can decrypt.
   Both keys are large numbers that are not duplicable.

2. a) Encryption ensures that message is sent securely and stays a secret so that it is not meant to be known or understood by the public in an open, unsecured network such as a public forum, but only by the intended receiver of that message.
   b) Digital Signature is for identification purposes and all about verifying WHO sent info or message, ensuring integrity of message.

[SimonO]

1. Public keys are derived from private keys (but NOT vice versa) and are used to encrypt messages that can only be decrypted with the corresponding private keys. While public keys are available to anyone, private keys are kept secret by an individual. Private keys can also be used to sign messages in order to securely identify a particular user.

2. Message Encryption & Signatures

[David_Walsh]

@ivan

• Describe the concept of public and private key with your own words.
• What 2 use-cases can public key cryptography be used for?

1. Private Key is a very large randomly generated number and the public key is derived from the private key but this only works one way. The private key cannot be derived from the public key. This makes the private key so important in terms of not losing it or letting it fall into the wrong hands.

2. (1) A public key can be used to encrypted a message which may be sent over an open network and the intended recipient can then decrypt the message with the corresponding private key.
   (2) A public key can be used to received bitcoin but you need the private key to send bitcoin by signing the transaction with the private key generating a signature which can then be verified by the network.

[leemac]

1. The private key is a randomly generated number from which the public key is mathematically derived. The public key can be made publicly available for anyone to encrypt data with. Encrypted data can only be decrypted with the private key. The private key cannot be derived from the public key

2. Public key cryptography is used for encrypting data and for digitally signing data

[Gerard_Goldski]

1 A private key is a large random number generated by a computer. From this private key another computation is done to achieve a public key Then an address is made from the public key . Overall the message/transaction is digitally signed on the public key. Only the private key holder can do this. That is why it is paramount to protect the private key.
2. (A) Storing and protecting data… Health /Military/financial information systems.
(B) Verifying and protecting the ownership of data. The unique private key is the identifier and proves ownership.

[Lacho]

1. Describe the concept of public and private key with your own words.
We need it for Encryption.
The public key : Is the one you share.
The private:Is the one you use to encrypt the message.
Is a digital signature or finger print.
2. What 2 use-cases can public key cryptography be used for?

1. For ENCRYPTION.
   2… Is like a Digital signature.
   Use for: Identity and Integrity.

[Leo_T03]

1.Private/Public key is how you access and spend your address balance. Private is yours to keep and is used to sign transactions while the public is available for all to see.
2.Encryption & Digital Signatures for verification

[sweeesh]

1- The public key is the generated from the private key and it is what you may show to the world.

2- Two important use cases for public key cryptography are digital signatures and sending / receiving crypto.

[Jmsn]

1 - The private key is the randomly generated number from with all the other keys are generated, related to and controlled from.

2 - Digital signatures and encryption.

[cryptomarls]

1. Describe the concept of public and private key with your own words.
2. What 2 use-cases can public key cryptography be used for?

A1. A public key and private key is used to send and receive messages over an open source network.
For example when sending a message your computer generates a unique random number, this is your private key and this is the key you would need to send/receive messages. this key MUST be known only to yourself and no one else. From this private key a public key is generated and this is the key that is sent over an open source network. This is the key everyone on the network can see. public and private keys work as a pair directly related to each other, It is also not possible to derive a private key from a public address it only works one way.

A2. The 2 use case scenarios a public key can be used in cryptography are encryption and digital signatures.

[Sarah]

1. A public key is derived from a private key. A public key cannot be used to access a private key. A public key can be shared with other people on the network. Its easy to create the public key given the private key, but its extremely difficult to calculate the private key from the public key.
2. Use cases for public key cryptography are Encryption and Digital signatures.

[Mauro]

@JustG

that are encrypted with the Private key can only be decrypted by using the Public key.

You encrypt with the public key, and decrypt with the private key. There is no point in encrypting with the private key if everyone will be able to decrypt it with the public key.

[GOMEZ]

1. Public key allows you to receive an encrypted message and private key allows you to be the only one to open it.

2. Send encrypted messages and sign transactions.

[Mauro]

@Karl

Questions:
The public key is generated by using private as input in a hash function.
The signature is generated by using the private key as input in another hash function.
How are public key and signature connected?
Or are public key and signature generated by same hash function, just by using different second input additional to private key?
How ist the process of taking signature and public key to verify signature? Is it a problem to be solved? A defined output to becreated like 0?

Please help

A public key is generated using the Elliptic Curve Digital Signature Algorithm. A signature is created by hashing, using the Digital Signature Standard. You can click on the Digital Signature Standard to see the book. I think it should have everything you need to know if you want to understand how public key and signatures are connected. In addition to that, I do recommend you check out the book called “Mastering Bitcoin” by Andreas Antonopoulos, as it
covers bitcoin in depth. Personally, I don’t think you need to got that much in depth, but if you want feel free to do so. Even I don’t fully know the math behind it. Hope that helps you out.

[Mauro]

@whip23

2.) Public key cryptography can be used to encrypt a message or be used to encrypt anything of value.

Encryption is one use-case. What is the other use case? Hint: We can’t verify transactions in bitcoin without it.

[Mauro]

@Javchisau

2. The function of the public key is to received a message also known as signature from a private key.

1st use-case: A public key is used to encrypt data, that can later on be decrypted with the private key.
2nd use-case: Once a private key signs a message/transaction (digital singnature), we can use the public key to verify that it was really signed by the private key. (without ever revealing the private key to the public).

[Mauro]

@RLion

author encrypts with own private key, receiver decrypt with author public key

@RLion

encrypt message’s with private key’s

There is no point in encrypting sensitive information if anyone can decrypt it with the public key. We want to encrypt it with the public key, so that only the private key owner can decrypt the sensitive information.

[Mauro]

You haven’t mention the encryption. How do we use the encryption with the public and private keys?

[Mike_C]

@ivan

1. Describe the concept of public and private key with your own words.
2. What 2 use-cases can public key cryptography be used for?

1. The concept is that you need both to complete the process. One side of the transaction needs the Private Key and the other side needs the Public key

In encrypted messaging, the receiver generates a Private key. A Public Key is derived from the Private Key. The sender uses the Public Key to encrypt the message. The receiver uses the Private key to decrypt the message.

In Digital Signatures, The sender generates a Private Key. A Public Key is derived from the private key. The sender uses the Private Key to digitally sign the message. The receiver uses the Public Key to verify the Private Key was generated by the sender.