Methods and apparatuses for controlling access to computer systems and for annotating media files. One embodiment includes a method including generating a challenge to a user, wherein the challenge includes a verify part and a read part. The methods also includes prompting the user to solve both the verify part of the challenge and the read part of the challenge; receiving input from the user; determining if the input from the user relative to the verify part of the challenge corresponds with the known answer for the verify part of the challenge; and identifying the input from the user relative to the read part of the challenge as an answer to the read part of the challenge, if the input from the user relative to the verify part of the challenge corresponds with the known answer for the verify part of the challenge.