Data Transmission · 4 question types
Past paper frequency (2018 to 2024)
This topic accounts for approximately 4% of your exam marks.
Symmetric vs asymmetric encryption questions are growing as cybersecurity becomes more prominent.
Symmetric encryption uses the same secret key to encrypt and decrypt. Both the sender and the receiver must have a copy of this key.
Symmetric encryption is fast and simple, but it has one serious weakness: how do you get the secret key to the other person in the first place?
You cannot send the key over the same network you want to protect, because the insecure link would expose the key just as it exposes the data. Possible ways to share a symmetric key:
If an attacker ever gets a copy of the shared key, every past and future message can be decrypted.