1. A method, comprising: receiving random subject matter sent from an authentication server to a client device for authentication of a user; prompting the user to draw the random subject matter at the client device as a first attempt to authenticate the user; receiving data describing a sketch of the random subject matter drawn by the user; sending the data to the authentication server for comparison to a freehand model describing sketching skills of the user; receiving a denial of the authentication indicating the data describing the sketch of the random subject matter failed to match the freehand model; sending another random subject matter with the denial of the authentication; and prompting the user to draw the another random subject matter as a second attempt to authenticate the user.