Systems and methods for providing identification tests. In some embodiments, a system and a method are provided for generating and serving to a user an animated challenge graphic comprising a challenge character set whose appearance may change over time. In some embodiments, marketing content may be incorporated into a challenge message for use in an identification test. The marketing content may be accompanied by randomly selected content to increase a level of security of the identification test. In some embodiments, a challenge message for use in an identification test may be provided based on information regarding a transaction for which the identification test is administered. For example, the transaction information may include a user identifier such as an IP address. In some embodiments, identification test results may be tracked and analyzed to identify a pattern of behavior associated with a user identifier. A score indicative of a level of trustworthiness may be computed for the user identifier.