Certificate Download Failed

Certificate Downloads Failed

Export Secret Key...

Your secret key could not be exported. Check the key.

And in fact this is gonna be the first part of the course, which is essentially once the two sides have a shared secret key, how do they use that secret key to encrypt and protect data that goes back and forth between them?

Shared Key

Shared

Send delay

So ... and therefore, the disc actually is the secret key. And as I said, this disc encodes a substitution table.

The only thing that's kept secret is the secret key k.

The secret key in the Enigma machine is the initial setting of the rotors. Okay.

Only they know the secret key k.

The first is secured key establishment and then how do we communicate securely once we have a shared key.

Alice and Bob know this secret key, but an attacker looking at the conversation has no idea what the key K is.

We already said that secured key establishment essentially amounts to Alice and Bob sending messages to one another such that at the end of this protocol, there's a shared key that they both agree on, shared key K, and beyond that, beyond just a shared key, in fact

Now once Alice and Bob have the shared key, you can use this key to communicate securely by properly encrypting data between them.

And the secret key is captured by this disc here, it's embedded inside of this disc, which rotates by one notch every time you press a key on the typewriter, okay?

And we'll see how to do that later on in the course.

But the attacker does not know anything about this key K. So now they're gonna use a cipher, which is a pair of algorithms, an encryption algorithm denoted by E, and a decryption algorithm, D. These algorithms work as follows the encryption algorithm

Welcome to the Secret Nightclub... Ah!

It's not that hard given enough ciphertext to directly recover the secret key and then the message.

Britain s Closet Keynesian

Yes, this is that nightclub...

We'll have a secret night...

Delete all key connections for this key?

The last key is the HELP CALC key

Only it's the wrong key! It is?

You would replicate the key and then you would subtract the key from the ciphertext to get the original plain text message.

We gotta get that key quick. Yup, yup. Key, key.

Annex 1 MDGs at a glance

Key

Key

Key

PUK

Key

Keys.

The keys!

The Secret History of the Financial Crisis

Japan s Secret Demographic Weapon

The Fiscal Crisis Down Below

The Secret Policeman s Fall

The Secret World of Female Circumcision

The voting will be held by secret ballot.

A ballot paper containing more names from the relevant region than the number of seats assigned to it will be declared invalid.

Was there a secret marriage?