Original: A specially noted variant of the chosen-ciphertext attack is the '' lunchtime '' , '' midnight '' , or '' indifferent '' attack , in which an attacker may make adaptive chosen-ciphertext queries but only up until a certain point , after which the attacker must demonstrate some improved ability to attack the system .
Simplified: A specially noted variant of the chosen-ciphertext attack is the '' lunchtime '' or '' midnight '' attack , in which an attacker may make adaptive chosen-ciphertext queries but only up until a certain point , after which the attacker must demonstrate some improved ability to attack the system .