Flashcards
SCC 363 - Crypto2
Flashcards do conjunto (12)
- 1State the two types of ciphers and state an example ?Transposition cipher - Skytale
Substitution cipher - Next - 2What happens to the letters in a transposition cipher?We do not change their letters but their orders
- 3What happens to the letter in a substitution cipher?Letters are changed, but their order remains the same
- 4Substitution is an example of a monoalphabetic cipher, what does this mean for the mapping of each letter?Each letter is always encoded to the same letter
- 5Vigenère Cipher is an example of a polyalphabetic cipher , what does this mean for the mapping of each letter?it applies shift ciphers with different keys to different text positions
- 6What are the three steps in cryptography?Precisely specify threat model
Propose a construction
Prove that breaking the construction under the threat mode will solve an underlying hard problem - 7What is known as the threat model?Formal model and definition of what security means
- 8What assumption do you have to make when trying to prove that breaking the construction under the threat mode will solve an underlying hard problem?Assumptions: Clearly stated and ambigous
- 9What does developing a precise threat model and security definition force the designer to think?It forces them to think about what they really want
– What is essential and – sometimes more important – what is not
– Often reveals subtitles of the problem - 10State some of the importance of models and definitions?Threat models and security definitions enable meaningful evaluation and comparison of schemes.
A clear threat model and security definition allows others to understand the security guarantees provided by some scheme - 11Models and definition enables schemes to be used as components of larger system? What is this known as? the termModularity
- 12State the importance of clear assumptions?Allows researchers to attempt to validate the assumption.
• Allows meaningful comparison between schemes based on different assumptions.
• Pratical implications in case assumptions turn out to be wrong.
• Enable proofs of security
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- dsdssd SCC 363 - Security and RIsk FlashCards sobre SCC 363 - Crypto2, criado por Ayo Olutobi em 17-10-2017.
- Criado por
- Ayo Olutobi
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