Private and Public Keys

Question 1

Define “Private Key Encryption”

Answer 1

Data encrypted by a single can that only the sender and receiver know.

This is called “Symmetrical Key Encryption”

Question 2

Define “Public Key Encryption”

Answer 2

The use of a Public key that is shared with many people, allowing them to access the documents that you encrypt using your private key.

Question 3

How does “Private Key Encryption” work??

Answer 3

1. A Sender encrypts a message with one of the private keys.

2. The Receiver can then use a copy of that private key to decrypt the message.

Question 4

How does “Public Key Encryption” work??

Answer 4

1. A Receiver can send out a public key that anyone can use to encrypt a message.
2. Keeping the private key, the receiver can then decrypt the message using their key.

Question 5

How can you add extra protection to a document, using the “Public Key Encryption”??

Answer 5

1. A Sender can encrypt using their private key, and then do so again with the Receiver’s public key
2. The Receiver can then decrypt the message and know what user has sent them the message, by using the appropriate Sender’s public key

Question 6

Define “Kerberos”

Answer 6

A way of data encryption that involves 3 Keys (3 headed Dog).

Question 7

Explain how “Kerberos” works

Answer 7

1. A User inputs their password to request access to a file(s).
2. Once the user is verified, the Authentication Server sends a ticket (Ticket Granting Ticket) and a key.
3. The TGT is encrypted, and given to the Ticker Granting Server for decryption using the key.
4. The user is given an encrypted token and a key, and then the File Server is given the token, and the key, and it decrypts the token.
5. The token is decrypted and the user is granted access to the File Server, but the token only allows access for a certain time.

Question 8

Where do all the Keys come in with “Kerberos”??

Answer 8

1. User and AS
2. User and TGS
3. User and File Server