Can someone explain asymmetric encryption ?

[AFB]

And if you could -:heart: -, would you explain symmetric encryption and key exchange?

Big THX to you

 

[beer]

I'm going to rip this straight from Wikipedia. I was asking these same questions earlier this summer. It clarified it for me.

An analogy which can be used to understand the advantages of an asymmetric system is to imagine two people, Alice and Bob, sending a secret message through the public mail.

With a symmetric key system, Alice first puts the secret message in a box, and then padlocks the box using a lock to which she has a key. She then sends the box to Bob through regular mail. When Bob receives the box, he uses an identical copy of Alice's key (which he has somehow obtained previously) to open the box, and reads the message.

In an asymmetric key system, instead of opening the box when he receives it, he simply adds his own personal lock to the box, then returns the box to Alice. Alice uses her key to remove her lock, and returns the box to Bob, with Bob's lock still in place. Finally, Bob then uses his key to remove his lock, and reads the message from Alice.

The critical advantage in an asymmetric key system is that Alice never need send a copy of her key to Bob. This substantially reduces the chance that a third party (perhaps, in the example, an corrupted postal worker) will copy a key while is in transit to Bob, allowing said third party to spy on all future messages sent by Alice. In addition, if Bob were to be careless and allow someone else to copy his key, Alice's messages to Bob will be compromised, but Alice's messages to other people would remain secret.

http://en.wikipedia.org/wiki/Asymmetric_key

 

[Cogman]

Is this the same as public key/Privite key. The description sounds simular, only in Public key/privite key instead of sending the box to bob where bob adds his own lock, bob just sends his lock to alice and she puts the lock on the box and sends it to bob.

A fun example (that I have messed a around with) is enigmail by mozilla.

 

[beer]

Originally posted by: Cogman
Is this the same as public key/Privite key. The description sounds simular, only in Public key/privite key instead of sending the box to bob where bob adds his own lock, bob just sends his lock to alice and she puts the lock on the box and sends it to bob.

A fun example (that I have messed a around with) is enigmail by mozilla.

I suggest reading the attached link. The postal-mail analogy is preferred because it doesn't mix the theory with the application. Asymmetric security is a theory; public/private key are the tools to which the application functions when it comes to information systems.

 

[AFB]

Well, can you go a little deeper into public/private key ? I'm just having a hard time understanding how you can't decrypt with them same key you encrypt with,

THX :beer:

 

[CTho9305]

Excellent explanation:
http://www.muppetlabs.com/~breadbox/txt/rsa.html