Several recent studies have underlined the need for trusted information displays in current and future personal devices. On the other hand, the display market is more and more dominated by low-cost flat-panel structures, driven by Thin-Film Transistor (TFT) circuits. Further, the quality of TFT-based electronics is constantly improving, allowing the fabrication of complicated electronic circuits on TFT technology. We have embarked on a project to implement cryptographic algorithms on polysilicon TFT technology. Our prototype designs will pave the way for secure display realisations combining cryptographic circuits and conventional pixel drivers on the same substrate. An experimental Data Encryption Standard (DES) coprocessor on polysilicon TFT technology is under development, while we are investigating a vector processor architecture to implement Elliptic Curve Cryptography (ECC)