CNIT 270 Midterm Exam (Latest Update
) Questions & Answers {Grade
A} 100% Correct
Active Attack Examples - correct answer Data modification and deletion, password
cracking, and denial of service
Passive Attack Examples - correct answer Eavesdropping/packet sniffing, keyloggers,
protocol analyzer
Error Detecting Codes - correct answer Parity, CRC, error correction codes, and hash
codes
Cryptographic One-Way Hash Function - correct answer *No secret key as input*
Accepts a variable sized message (M) and produces a fixed size output H(M)
,How can encrypted hash messages be authenticated? - correct answer symmetric or
public key encryption
Hash Function Requirements (Basic) - correct answer 1. H can be applied to a block of
data of any size
2. H produces a fixed-length output
3. H(x) is relatively easy to compute for any given x
Hash Function Requirement: One-Way (Preimage Resistance) - correct answer Given:
Hash
Find: Any two messages that match that hash
Hash Function Requirement: Second Preimage Resistance - correct answer Given:
Message
Find: Another message with a hash that matches the first
, Hash Function Requirement: Strong Collision Resistance - correct answer Given: No
Constraints
Find: Any two messages with the same hash
Level of effort required is proportional to the following given the length, n, of a hash
code: - correct answer Preimage Resistance: 2^(n)
Second Preimage Resistant: 2^(n)
Collision Resistant: 2^(n/2)
Kerckhoff's Principle - correct answer 19th century Dutch cryptographer
A cryptosystem should be secure even if
everything about the system, except the key, is
public knowledge
The security of the encrypted message depends
) Questions & Answers {Grade
A} 100% Correct
Active Attack Examples - correct answer Data modification and deletion, password
cracking, and denial of service
Passive Attack Examples - correct answer Eavesdropping/packet sniffing, keyloggers,
protocol analyzer
Error Detecting Codes - correct answer Parity, CRC, error correction codes, and hash
codes
Cryptographic One-Way Hash Function - correct answer *No secret key as input*
Accepts a variable sized message (M) and produces a fixed size output H(M)
,How can encrypted hash messages be authenticated? - correct answer symmetric or
public key encryption
Hash Function Requirements (Basic) - correct answer 1. H can be applied to a block of
data of any size
2. H produces a fixed-length output
3. H(x) is relatively easy to compute for any given x
Hash Function Requirement: One-Way (Preimage Resistance) - correct answer Given:
Hash
Find: Any two messages that match that hash
Hash Function Requirement: Second Preimage Resistance - correct answer Given:
Message
Find: Another message with a hash that matches the first
, Hash Function Requirement: Strong Collision Resistance - correct answer Given: No
Constraints
Find: Any two messages with the same hash
Level of effort required is proportional to the following given the length, n, of a hash
code: - correct answer Preimage Resistance: 2^(n)
Second Preimage Resistant: 2^(n)
Collision Resistant: 2^(n/2)
Kerckhoff's Principle - correct answer 19th century Dutch cryptographer
A cryptosystem should be secure even if
everything about the system, except the key, is
public knowledge
The security of the encrypted message depends
