(cryptography) An attack on a cryptosystem that relies on the attacker's ability to choose any plaintext of their liking and encrypt it into the corresponding ciphertext with that system and key. More powerful than a known-plaintext attack but less powerful than a chosen-ciphertext attack.

(cryptography) An attack on a cryptosystem that relies on the attacker's ability to choose any ciphertext of their liking and decrypt it into the corresponding plaintext with that system and key. More powerful than a chosen-plaintext attack.

The state of being chosen, especially that of being the Chosen People.