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Networks and the Internet
Quick questions on Network security and encryption explained: H2 Computing
6short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is symmetric encryption?Show answer
Symmetric encryption uses a single shared secret key for both encrypting and decrypting. It is fast and good for bulk data, but both parties must already share the key. That raises the key-distribution problem: how do you get the secret key to the other party over an insecure network without it being intercepted?
What is public-key (asymmetric) encryption?Show answer
Public-key encryption uses a key pair:
What are hybrid systems?Show answer
Real systems combine both. In TLS (HTTPS), slow public-key encryption is used once to securely agree a symmetric session key, then fast symmetric encryption protects the actual data. This hybrid scheme gets the security of public-key exchange with the speed of symmetric encryption.
What is q1?Show answer
In public-key encryption, which key encrypts a confidential message and which decrypts it? [2 marks]
What is q2?Show answer
Why is symmetric encryption used for bulk data even when public-key encryption is available? [1 mark]
What is q3?Show answer
How does a digital signature prove a message was not altered? [2 marks]
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