Verifying Human Use of Electronic Systems

Described herein are techniques related to verifying human use of electronic systems. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope and meaning of the claims. A user-interaction module obtains a user's request to access and/or utilize an electronic system. A plain-text call generator in conjunction with a randomizer generates a random plain-text call. A modifier rule generator in conjunction with the randomizer generates a modifier rule. The user-interaction module transmits the random plain-text call and the random modifier rule to the user and obtains a response from the user. A comparison module compares the response by the user with an expected response and informs a verification module of the result. The verification module indicates a denial of access if the obtained response and expected response differ, and grants access if the obtained response and expected response match.