Of the following, in which type of an attack does the attacker try every possible key with the decryption algorithm, knowing that eventually one of the keys will work?

A chosen-ciphertext attack lets the attacker submit arbitrary ciphertexts to a decryption oracle and study the resulting plaintexts to derive key information, rather than trying every key.

A ciphertext-only attack is a constraint describing what the attacker possesses - only ciphertext samples - and does not specify the method of key recovery used.

A brute-force attack operates on the assumption that trying every key in the key space will eventually produce a recognizable plaintext, making success guaranteed given sufficient time and computational resources. The feasibility of this attack is directly tied to key length - longer keys create exponentially larger key spaces that make brute-force impractical. It requires no knowledge of the algorithm's structure or weaknesses.

A birthday attack leverages probability theory to find two inputs producing the same hash output, targeting hash function collision resistance rather than symmetric key recovery.