This article proposes a video-based identification authentication framework via signature verification and pen-grasping posture analysis. The authors consider the case of using a camera instead of a pressure-sensitive tablet to acquire signatures. The proposed reliable verification method is useful when pressure-sensitive digitising tablets are not available. In addition, the authors can acquire more information in addition to the trajectories of the signature in video-based handwritten signature verification. The entire writing process and the pen-grasping posture are personalised features that cannot be easily imitated and forged. The authors analyse the signature trajectories using curvelets and the pen-grasping posture using modified motion energy images to perform user-dependent identification authentication. The proposed system is able to achieve both low false-rejection rates and low false-acceptance rates for database containing both unskilled and skilled imitation signatures.