A(n) ________ is a text box and a list that is hidden until you click its arrow

Eve has bet Bob that she can figure out the AES secret key he shares with Alice if he will simply encrypt 20 messages for Eve using that key. For some unknown reason, Bob agrees. Eve gives him 20 messages, which he then encrypts and emails back to Eve. What kind of attack is Eve using here?

What will be an ideal response?

The binary system uses the numbers ________ to represent digits

Fill in the blank(s) with correct word