13151875
Description
Flashcards by sss tttttt, updated more than 1 year ago
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Created by sss tttttt
over 6 years ago
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| Question | Answer |
| What is the importance of models and definitions? | Models and definitions aid understanding of the task to be achieved |
| What do threat models and security definitions enable? | Evaluation and comparison of schemes |
| What does a "clear" threat model and security definition allow? | Understanding of the security guarantees provided by the scheme |
| A clear threat model and security definition enables... | schemes to be used as components of a larger system (scheme modularity) |
| Cryptography currently requires 4 computational assumptions, one of which is... (1) | 1. Allowing researchers to validate the assumption |
| Cryptography currently requires 4 computational assumptions, which are... (2) | 2. Allowing meaningful comparison between schemes based on different assumptions |
| Cryptography currently requires 4 computational assumptions, which are... (3) | 3. Practical implications in case assumptions are wrong |
| Cryptography currently requires 4 computational assumptions, which are... (4) | Enabling proofs for security |
| Skytale is an example of a... | transposition cipher |
| In a transposition cipher, what is kept the same and what is changed? | Letters are not changed, but letter order IS changed |
| The Caesar cipher is an example of a... | substitution cipher |
| In a substitution cipher, what is kept the same and what is changed? | Letters are changed but their order remains the same |
| When using modular arithmetic what are we looking for? | The number that occurs as a remainder when one number is divided by another |
| 8 mod 3 = ? | 2 |
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means...
Image:
Image (binary/octet-stream)
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the elements from {0...N-1} |
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(CAN...)
Image:
Image (binary/octet-stream)
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Can be used to identify the alphabet in which A=0 ... Z=25 |
| The caesar cipher has a shift amount of... | 3 |
| 25 = 35 mod 10 why is this correct? | (25-35) = 10 which can be cleanly divided by 10 |
| 25 != (35 mod 10) why is this correct? | (35 mod 10) = 5 which is not equal to 25 |
| 5 = (35 mod 10) why is this correct? | (35 mod 10) = 5 which is equal to 5 |
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Ring of Congruence Example
[3] + [4] = [7] = [2]
{... -8, -3, 2, 7 ... }
What is the significance of Z5?
Image:
Image (binary/octet-stream)
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ZN is the N that we use to divide... in this case 5 |
| ROT13 is an X that has a key of Y | shift cipher that has a key of 13 |
| The Vigenere cipher is... | polyalphabetic |
| The Vigenere cipher applies... | several substitution ciphers with different keys to different text positions |
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