Adam, a malicious hacker, has just succeeded in stealing a secure cookie via a XSS attack. He is
able to replay the cookie even while the session is valid on the server. Which of the following is the
most likely reason of this cause?

A.
No encryption is applied.

B.
Two way encryption is applied.

C.
Encryption is performed at the network layer (layer 1 encryption).

D.
Encryption is performed at the application layer (single encryption key).

Explanation:

Single key encryption uses a single word or phrase as the key. The same key is used by the
sender to encrypt and the receiver to decrypt. Sender and receiver initially need to have a secure
way of passing the key from one to the other. With TLS or SSL this would not be possible.
Symmetric encryption is a type of encryption that uses a single key to encrypt and decrypt data.
Symmetric encryption algorithms are faster than public key encryption. Therefore, it is commonly
used when a message sender needs to encrypt a large amount of data. Data Encryption Standard
(DES) uses the symmetric encryption key algorithm to encrypt data.