Question

How does key-encryption work?

Scenario: You want to send a secret message to your friend. But someone can see everything you and your friend send out.

I've learned something about private key encryption but I'm still confused on how it works.

Answer 1

This is what I know so far:


You multiply your message by your private key 'A"
And you send 'AM' to your buddy.

Your buddy multiplies his key to it and sends it back, which is 'BAM'

Now you and your buddy have 'BAM', but how do you get it back to 'M'?
I'm assuming you can't divide in this scheme.

Answer 2

@Ultrilliam

Answer 3

Only one user actually has the private key, the user who is getting sent the mail. The mail is encrypted using the public key, of which only the private key can decrypt.

Let's do this in terms of SSH into a server, as it might be easier to explain.
The server has a Private key and a public key, right?
When you attempt to establish a connection, the server sends along the public key, and you send it the private key. You then enter what's supposed to be the original phrase, and the server decrypts the public key, and see if the phrase matches what's entered.

Now as for the nitty gritty of how it works, essentially a cipher.
https://www.youtube.com/watch?v=liKXtikP9F0 explanation of AES

Answer 4

Video is too long xd, can you make an example yourself showing how the private key can decrypt the public key-encrypted message?

Answer 5

"Ain't nobody got time for that"
https://crypto.stackexchange.com/questions/48294/how-exactly-are-public-and-private-keys-used-to-encrypt-and-the-decrypt-data

Answer 6

wow it's a lot more complicated than I thought then. thnx for links

Answer 7

No prob, =P