CCP Cryptography & Information Security

Question 1

Which type of encryption uses the same key for both encryption and decryption?

Accepted Answer

Symmetric encryption

Answer

Symmetric encryption uses a single shared secret key for both encrypting and decrypting data, making it fast but requiring secure key distribution.

Question 2

What is the key length used by AES-256?

Accepted Answer

256 bits

Answer

AES-256 uses a 256-bit key, which is the longest standard key size for AES and provides the highest security level of the AES variants.

Question 3

Which property of a cryptographic hash function ensures that two different inputs cannot produce the same hash output?

Accepted Answer

Collision resistance

Answer

Collision resistance means it is computationally infeasible to find two different inputs that produce the same hash output.

Question 4

What distinguishes a hash function from encryption?

Accepted Answer

Hashing is a one-way function with no decryption key

Answer

Hashing is a one-way function designed to be irreversible; there is no key and the original data cannot be recovered from the hash.

Question 5

What cryptographic concept ensures that a sender cannot later deny having sent a message?

Accepted Answer

Non-repudiation

Answer

Non-repudiation, typically achieved through digital signatures, prevents a sender from denying authorship of a message they signed.

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