1.Private key is masterkey, converts to public key(encrpyted) then from here if any transcation occurs it will be signed off with a piece of private +block
2. BTC and ethernum
Describe the concept of public and private key with your own words.
-a private key is a random, but very large number generated by personal computer as a unique identifier to the user. Only the user computer has knowledge of this key. The public key is a function generated from the private key and can be broadcast as public knowledge as an identifier for that particular user/computer
What 2 use-cases can public key cryptography be used for?
The privat key is literally the key to my public key. The private key is best kept private whereas my public key can be shared with others. Another person can encrypt a message with my public key, which I can decript by using my private key.
a. It can be used to encrypt a message.
b. It can be used to generate a bitcoin address, hence therefore it can be used to receive a digital currency
These are two steps of the same thing - encryption 
the other use case are digital signatures which are more heavily used in digital currencies.
Describe the concept of public and private key with your own words.
the computer create automatic a random numbers which is secret and called a private key.
public key can be view and share with everyone.
What 2 use-cases can public key cryptography be used for?
Encryption
Digital signatures
A private key is a random number generated by a users computer that is kept secret. A public key is generated from a private key, but the private key cannot be deduced from the public key. A public key can be used to encrypt data that only the private key can decrypt.
Encryption and digital signatures
private key you better keep safe,its your unique digits for logins
public key u can see on etherscan as proof of transaction, and proof of identification.
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1. Describe the concept of public and private key with your own words:
A public key can be described as an account number; mathematically connected to the private key. The private key can be described as a password.
2. What 2 use-cases can public key cryptography be used for?
Two examples of use-cases are; encrypted messaging and digital signatures, pertaining to transactions.
2 Encryption and Digital signatures.
cryptocurrency and public key signing digital documents to verify it was you who sent the message.
Private key is what I keep secret. The public key is generated from the private key but everyone can see. I can send a digital signature with the public key in which they can verify its generated from my private but they can never see what the private key is unless its stolen.
Encryption and digital signature e.g sending and receiving encrypted messages. Digital signing sending transactions or verifying receiving transactions.
SHA256 is not used to derive public keys, for that the Elliptic curve function is used. Public keys are hashed to get the address. 
Transactions utilize digital signatures to function. PK cryptography can also be used for encryption.
Describe the concept of public and private key with your own words.
Public key is the key shared with the public that they can use to encrypt the data sent to me. The Private Key is the key that allows me to uncrypt the messages sent from other people who used public key.
What 2 use-cases can public key cryptography be used for?
A user can create private key from a random generated number, as the name implies, this number should be kept private. From the private key a public key can be generated to then share with other users. To make transactions between senders and receivers the senders need to sign those transactions with a private key, to proof that they have access to funds. The receiver can then compare the signature (encrypted private key) of the sender with the public key of sender to verify the senders identity and integrity.
Private keys are yours and yours only. Your private keys should be kept secure. Private keys generate public keys which are public to everyone. When someone sends you a message or money, only your private key can be used to decrypt that message. Public keys can’t be used to decrypt private messages.
A) Encryption- To send a message to someone over an open , non secure network, you can encrypt your message to someone.
B) Digital Signatures- For Bitcoin transactions, you utilise someone else’s digital signature and their public key to verify that they wanted to send you a transaction.
You can go from a private to a public key – one way street – but not from a public to a private key. The pubic key is derived from the private key. Anyone can use a public key to encrypt a message
Encryption and Digital signature are two use cases.
A public key is accessible to all, and is linked to a private key that no one else but the owner can access. The private key is a random number generated by a computer, that only its owner has access to, hence must be kept safe and secret, since the private key decrypts the content of the public key, but not the other way around.
It can be used for encryption purposes, or for digital signatures, in the case of Bitcoin.