A private key is used to make and sign transactions. It must be kept secret by any means and is used to decrypt messages sent to my public key. The public key, as the name indicates it, is public meaning everyone can see it. It is automatically generated by a private key and it is used to receive funds / information from someone.
Encryption : I will receive from someone an encrypted message on my public key (which everyone can see) and I will be able to decrypt it with my private key linked to my public key
Digital signature : Everyone sees my transaction on the Blockchain and nobody will be able to change it. The simple fact that my public key is visible on the Blockchain means that my transaction was signed digitally. Immutability leads to transparency.
Your computer generates a Private Key, with that private key you generate a public key with a formula. There is no way for anyone to get the private key from a public key and because of this, the public key can be shared with others.
Encryption and Digital Signatures. In encryption, the public key is shared, with that public key a message is encrypted and it can only be decrypted with the private key that generated that public key. In digital signature, the message is signed with the private key. With the signature and the public key, you can verify that the signature was created with the private key that generated that specific public key.
Describe the concept of public and private key with your own words.
Public Key encrypts a message and is available for the public to see, Private Key is used to decrypt the message and is not available to the public.
What 2 use-cases can public key cryptography be used for?
To encrypt a message OR as a digitally unique signature.
Private key is a random number that should stay secure, and when computed in a hash function it transforms into the public key. The public key can be shared because itâs impossible to reverse the function and guess the private key. In the other way, itâs possible to prove that we have the private key and thus the control of the public key by computing it into the hash function. Public key is like the door step with the name, and the private key the key to open it, but in way more secure.
Encryption, and digital signature.
Question : if we sign a message with the private key, isnât it possible to find the private key by reading the message ? I have not very well understood this part.
1 - both keys are very large HEX numbers. The private key is generated randomly and then a formula generates a public key from it. The private key needs to be secured at all times and the public key can and should be shared with others.
2 - Encryption and Digital Signatures.
A private key is a very large random number, large enough that collisions are practically impossible. The public key is derived from that private key using hash functions, in such a manner that reversing back to the private key is impossible. The public key is shown to the world. When you sign a message using your private key, the world knows you sent that message, because they can verify that the private key used to sign it was the same as that which generated the public key. This is used in Bitcoin to sign txs, so they know the owner of the Bitcoins is the one trying to spend them.
a) Encryption, wherein you can encrypt your messages to a specific person such that only the owner of the private key whose public key you used to encrypt can decrypt it.
b) Digital signatures, wherein you sign a message to prove that you really sent it. The world can verify that the owner of the private key that generated your public key was the one who signed the message, which would have to be you, assuming no one stole the private key.
Public keys are like a unique identification or signature which are created from the private key. Public key are some kind of identify proof of the wallet or subject while private keys are the secrets to utilizes the functionality of the subject or wallet (For example you can move or send your coins in the wallet using your private key only)
The two use cases are Encryption and digital signature.
So once You open a wallet, You get Your private key, which gives You and only You access to Your wallet. If You lose it You lose your wallet.
Public key is generated from your private key and works as a wallet for some1 else to sendcoins to Your wallet but without the option of accessing and using Your wallet.
1st You can encrypt a messege useing some1 private key in a way that only they will be able to decypher the messege using there private key.
2nd You can sign a messege You send to some1 so that they can check Your signature with Your public key.
Answers:
Homework on Public and Private Keys - Questions
Describe the concept of public and private key with your own words.
Ans: We need to keep our private key secret and safe because it is used to generate our public key that is used to send and receive Bitcoin. We can also add a Bitcoin address from the public key to add an extra layer of security. It is impossible to go backwards by trying to use a public key and determine what the private key is. That is why we need to protect our private keys because if someone has our private key, then they could âdigitally signâ a transaction and take our Bitcoin.
What 2 use-cases can public key cryptography be used for?
Ans: 1.) encryption 2.) digital signatures
1.The private key a random number generates the public key also a random number. The private key is only known by the wallet owner. The private key is used to singe a transaction or to encrypt a message from one wallet to another wallets public key, in case of BTC to a Bitcoin address generated from the receiverâs public key.
The senders public key is used to decrypt the message.
A private key is a large, randomly generated number. It is only known by the holder of the private key. With the private key number, a function is performed that generates a public key. The public key is then shared. The function that generates the public key is a one way function, meaning you cannot generate the private key from the public key. Whoever has the public key can encrypt information with it. That encrypted information is then unreadable to anyone except the holder of the private key. The private key can be used to decrypt the information.
1- Private key is randomly generated number by your computer that is used as the root for the generation of public keys, which are strings of characters that allow third parties to send you sensible info or assets through public networks.
2- encryption and signatures
No, your private key wil produce a digital signature for a certain message + receivers public key. The receiver can verify this signature using your PUBLIC key. Because your public key can only be calculated from the according private key, you donât need to expose your private key!
If you want more information in dept, Watch this:
Not only by hash functions, but by Eleptic curve Cryptography.
Check this awesome post:
https://medium.com/coinmonks/private-and-public-key-cryptography-explained-simply-4c374d371736
The public key is not random but derived from the private key using Elliptic curve cryptography, that public keys can be proven that it is generated by a particular private key without revealing it
You donât really share your public keys, but your bitcoin address, wich is derived from your public key by performing some type of double hash. Also, every new transaction you make will generate a new address. So as long you never reuse the same address, nobody can know how much bitcoin you own. Only your private keys can know wich bitcoin addresses belong to you