Alice intends to send a secure message to Bob. (i) What are the threats that Alice...
Alice intends to send a secure message to Bob. (i) What are the threats that Alice should be concerned about in sending messages to Bob? (ii) What information does Alice need if symmetric key encryption is used? (iii) What is needed if asymmetric key encryption is used? (iv) Is encryption alone sufficient to defend against these threats?
Homework Answers
(i) The threats that Alice should be concerned about in sending messages to Bob are :-
1. Masquerade
2. Traffic Analysis
3. Data Modification
4. Sequence Modification
5. Timing Modification
(ii). Alice needs a key to encrpt the information or data if symmetric key encryption is used.
(iii). Bob’s public key is needed if asymmetric key encryption is used.
Explanation :-
* If Alice intends to send a secure message to Bob and she wants to encrypt the message using asymmetric cryptography by using Bob’s public key so that no one other than Bob can read it.
(iv). Encryption is not alone sufficient to defend against these threats.
Explanation :-
Because encryption does not provide authenticity as well as integrity. and it is vulnerable to message modification:
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