1. What is a cipher that replaces one letter for another, possibly retaining the letter frequency of the original message?
- brute-force
- cryptanalysis
- nonrepudiation
- substitution
- transposition
- Vigenère
Explanation: A substitution cipher replaces one letter for another, possibly retaining the letter frequency in the cleartext language.
2. What is a method of cryptanalysis in which an attacker tries every possible key knowing that eventually one of them will work?
- brute-force
- cryptanalysis
- nonrepudiation
- substitution
- transposition
- Vigenère
Explanation: In a brute-force attempt to decipher a coded message, every possible value is attempted.
3. What cipher method does 3DES use as part of the algorithm?
- brute-force
- cryptanalysis
- nonrepudiation
- substitution
- transposition
- Vigenère
Explanation: A transposition cipher is used in part by the legacy 3DES algorithm.
4. What is the term for when a device cannot refute the validity of a message that it has received?
- brute-force
- cryptanalysis
- nonrepudiation
- substitution
- transposition
- Vigenère
Explanation: Nonrepudiation means that a device cannot refute the validity of a message sent.
5. What is the practice and study of determining the meaning of encrypted information, without access to the shared secret key?
- brute-force
- cryptanalysis
- nonrepudiation
- substitution
- transposition
- Vigenère
Explanation: Cryptanalysis is the study of determining the meaning of coded messages without access to message key.