Secure processor architectures enable new sets of applications such as commercial grid computing, software copy protection and secure mobile agents by providing secure computing environments that are immune to both physical and software attacks. Despite a number of secure processor designs have been proposed, they typically made trade-offs between security and efficiency. This article proposes a new secure processor architecture called M-TREE, which offers a significant performance gain while without compromising security. The MTREE architecture uses a novel hierarchical Message Authentication Code Tree (MACTree) for protecting applications' integrity at a minimal performance overhead. M-TREE also introduces a new one-time-pad class encryption mechanism that accelerates security computation over the existing block cipher-based schemes with high security guarantee. Based on the results of our performance simulation, the performance overhead of the M-TREE integrity check mechanism ...