1. The concept of the public and private keys.
Private keys are code derived from hashed information which, in a one way function produce public keys. Public keys are shared and private keys never should be shared. The public key is shared and allows others to encrypt data that you can decrypt with the private key.
2. 2 use cases for public key cryptography.
1. Encryption
2. Digital signaturesThis is both done by utilizing digital signatures, the other use case is encryption. 
private key is in my regular world the password/access to my bank account. My bank account number which i provide to everybody to receive money is my public key.
signing transactions and encryption
A public key is an personal identifier that can be shared with everyone to send or receive message etc. A private key is used to encrypt or send message or funds to individuals. The main difference is your private key should not be shared with anyone, while your public key can shared with the general public to identify yourself.
Encryption and Digital Signatures
private key is signature to a transaction public key is way to receive transactions
send encrypted messages or transactions on a unsecured network
and also to verify a particular message
Describe the concept of public and private key with your own words.
A: If you don’t own your private key you do not own your funds. The private key is a secret code that is generated by your “computer” only for you to remember and never share. The private key is also used to generate a public key, which is available to all to view on the blockchain. That public key of the receiver is used to encrypt whatever message/transaction from the sender, where only the private key of the receiver can decrypt and view the message (also the sender). From the sender side, the sender will sign the transaction with their private key (encrypted) where the receiver can then validate that it came from the correct public key or Sender. Also, this is a one way street where private key can derive the public key, however you cannot derive the private key from the public key (rather infeasible as taught in a previous lesson).
What 2 use-cases can public key cryptography be used for?
A: Most services that that transact today is a good use case for this technology. It will streamline the process, providing a TRUST based system. To name a few use cases, supply chain to validate from end to end that its integrity and quality expected is maintained. Finance all transactions, music and entertainment industry giving the authority to artists and actors to reach out to humanity without the middlemen, voting, government governance etc.
1: A public key will encrypt a message, a private key will allow you to decrypt a message. A private key will also confirm that it has created a public key thus creating a digital signature.
2: Encryption and digital signatures.
I think most of the examples you described in the second answer are cases for digital signatures, but you can also do encryption
Public key is like your email account, one party can connect and communicate to another party through a common domain.
Private keys are like the passwords to the email account. If Party A performs a transaction to Party B, Party A has his own password to open his own account to do it. Party B will need his own password, like a private key, to open the email/platform/website to see what the transaction is.
(a) Encryption of messages from one party end to another party end
(b) Digital signature: combination of sender’s private key and public key to verify the identity of the sender.
Public and private keys are used to encrypt transactions and data (messages and funds) from peer to peer. Individuals are able to privately own and exchange assets and information through the public and private key system. The private key is created through a cryptographic hash and acts as the singular key to approve transactions sent through the network. The public key is created from the private key and is used to represent individuals on the network. Any encrypted data or funds sent to the public key can only be unencrypted by the private key.
Public key system can be used to privately and securely send messages.
The public key system can also be used as for digital signatures.
1.A private key is a large random number that is then used to produce the public key. In encryption, information can be sent using the public key but the person the receives it must have the private key to be able to decrypt the information sent. With digital signatures, the private key is used to sign a message or transaction. The public key is compared to see if the signature is genuine.
2. Encryption such as sending messages and Digital Signatures to validate that a specific user created a transaction.
The Public Key is created from the Private Key. Only the Private Key can sign transactions to spend the funds, and no one can access the private key from the public key.
To send encrypted messages to another party so that if anyone seeing the message being sent, only sees “gibberish”. And in the case of Bitcoin, to send or receive funds to another party without the spending key (private key) being compromised.
It is a pair of numbers: a randomly generated private key and a public key deriviated from it. The connection between the numbers can provide cryptographic security as long as the private key is kept in secret. The public key can be openly distributed.
Encryption of messages that are only meant for the owner of the private key and identity verification through digital signatures.
The private key is the core password to your wallet and its also used to verify the identify of oneself. The public key is a random generated password derived from the private key which is used to encrypt messages or transactions.
Use cases for private and public cryptography is sending transactions through the Bitcoin network, signing sensitive documents digitally, encrypting sensitive messages, emails, documents.
Private keys are only to me seen by the owner of that wallet. In the case of bitcoin they are used to sign transactions from that account to verify they are legit by the owner. Public keys can be seen by the public and can be used to send the transactions to. Similar to how mail is sent to your street adress.
Encryption and digital signatures
A private key is random number generated by your computer or crypto wallet. Once the private key is generated it is used to create a public key. That public key can then be used to encrypt a message and only the private key can decrypt it. It is similar for digital signatures. The private key is used to create a digital signature. The digital signature can be used to verify that the private key that generated the public key is also the one that generated the signature.
Public key cryptography can be used for encryption and digital signatures.