A public key can be used to encrypt a message that is being sent to me, and that message can only be decrypted using my private key. So in short it’s genius stuff.
One would be bitcoin addresses. Works the same way as a public key would. One other can be message encryption through public channels.
Public and Private key cryptography is a system by which a set of keys is utilized to execute a one way function. Public keys can be known by anyone whereas the private key is only known by the owner. When two entities would like to transfer data or perform a transaction where the communication must be private and secure between the entities a level of security can be added to the message; thus only allowing the party with the correct key to decode the message.
Public key cryptography can be used for encryption and digital signatures for messages.
Describe the concept of public and private key with your own words.
A Private key is a randomly generated large number that must be kept secret, using this number to generate another number ( i assume with sha-256) this output number is the public key. now you can use the private key to sign messages or transactions and because the signature and your public key were both generated by the same private key, the fact you sent the message or transaction can be verified.
What 2 use-cases can public key cryptography be used for?
Identification or encryption of data
When someone sends a message to your public key that is signed with their private key, you see that you got a message from the persons public key, and need your private key to open the message.
The private and public keys are like hashing functions, it is mathematically impossible to find out a private key by having it’s public key.
Use cases for public key cryptography:
Sending encrypted private messages.
Digital signatures.
Public and private keys are the ways that you can send encrypted messages and have a digital signature attached to verify that you sent the message. The private key generates your public key
Public key is derived from the Private key which is generated from a random number.
With a public key, you can encrypt a message or a transaction you want to send.
A private key lets you decrypt a message or a transaction.
a) You can use a public key to encrypt a message you want to send to someone.
b) Bitcoin addresses are hashes of public key it can act as proof of ownership of bitcoins.
Describe the concept of public and private key with your own words.
A: Public and private keys are a means by which to securely send and receive messages, information, data, currency, etc. The private key is a random number that is generated by one’s computer and is meant to be kept secret by the holder of that key. The private key then generates a public key by which can be shared with the world.
What 2 use-cases can public key cryptography be used for?
A: Encryption and digital signatures. Digital signatures is the form that is used within cryptocurrency.
A private key is used by the receiver to decrypt messages that were sent using their public key for encryption. A private key can also be used to generate a digital signature when sending messages to others as a means of enabling receivers to identify the public key of a sender. This however, would not be used to encrypt any messages. Requiring the receivers public key as the mechanism to encrypt the message to be sent.
Public key is used to encrypt and decrypt the data. The Private key is shared between the sender and receiver to verify who the data is going “to” and “from”.
Digital signature and encryption are two use-cases public key can be used for.
A private key is just a very large random number. The public key is a value derived from a function using the private key as the input.
The two use cases are digital signatures and encryptions.
Public-key cryptography allows a secret Private Key randomly chosen from a VERY, VERY, VERY Large space or even a private key with the value of ONE or TWO or 1959, the year of my birth, to derive public keys that can be freely shared on unsecured channels and then any message encrypted with a derived public key can be decrypted with my private key such as 1959. This is in contrast to systems of encryption where the one secret key used to encrypt and decrypt has to be shared by some secure channel. Worst is when you want to change that secret key often. Publc/Private key cryptography has been a staple of the most secure systems for some time now.
Encryption, Identity, and Digital Signatures: The most prevalent and popular use cases are encryption of messages using a public key and the owner of the private key being able to decrypt the message. Using a public key to be sure that a particular message was indeed digitally signed by the owner of the private key paired with that public key.
A private key is the encrypted version of the public key that is visible on the blockchain. It is virtually impossible to decrypt a private key due to the endless mathematical possibilities.
A public key is perfect for receiving a cryptocurrency, because the private key is protected by encryption you can safely give your public key to someone that wants to send you crypto. The second use case would be provenance as mentioned earlier in this course, you can use the blockchain ledger to verify if a public key has or previously had crypto and who they sent or received the bitcoin from.
Addresses are hashed just for the purpose of conserving space on the blockchain, hashes are smaller than public keys.
The other use case for public key cryptography however is digital signatures. 
This is an example of a digital signing. The other use case is encryption.
Cryptocurrencies like Bitcoin mostly utilize digital signatures and what you explain are all examples of it. You can also use them for encryption.
You mean encryption? 
Homework on Public and Private Keys - Qs
Describe the concept of public and private key with your own words.
A private key (large random number) can generate a public key (shared on the internet) but you can never guess the private key from knowing the public key.
To send an encrypted message, one party will communicate their public key and the latter can send a message encrypted in that public key which can only be read/decrypted by the owner of that private key.
What 2 use-cases can public key cryptography be used for?
Encryption and digital signatures
Thanks Alko, to give me some pointers, read more about it had some issues wrapping my head around decrypt and encrypt, data or message and digital signature and the two use case of public key. tell me if I’m right.
A. so basically you can decrypt a digital signature with the sender public key and compare them with the ash of the same data if you are the receiver.
B. With a public key you can encrypt a message or data you want to send with the public key of the recipient.
