Mojo-V: Secret Computation for RISC-V

Summary

Mojo-V: Secret Computation for RISC-V Mojo-V (pronounced “mojo-five”) is a new RISC-V extension that introduces privacy-oriented programming capabilities for RISC-V. Mojo-V implements secret computation, enabling secure, efficient, and data-oblivious execution without reliance on fragile software and programmer trust. By sequestering sensitive data in dedicated secret registers and encrypting memory under a third-party key, Mojo-V prevents disclosures and enforces computation that is both blind (no direct disclosures) and silent (no side channel leakage). The design integrates seamlessly into the existing RISC-V ISA with only a mode bit and four new instructions, enforced entirely at decode. Early results show near-native execution speeds while offering over 5-7 orders of magnitude performance improvement compared to fully homomorphic encryption (FHE), with a clear roadmap for integration into CPUs, GPUs, and specialized accelerators. To learn more... Here is an intro video describing Mojo-V: https://www.youtube.com/watch?v=HUT46TcNyyM Slides that give an overview of the Mojo-V project: https://drive.google.com/file/d/1VVzZqYHvQgnKMgXZjg7I_cX2GzF7awSN The current Mojo-V ISA Extension Specification (release 0.91): To contact the developers of Mojo-V: 🧩 Mojo-V Reference Platform — Release 0.91 🚧 Project Status The Mojo-V reference platform release 0.91 implements secret integer and floating-point computation using a fixed symmetric key cipher. As of this release, 64-bit secret computation is fully secretized and this early reference platform can be used for software development and red-teaming. Additional capabilities will be rolled out in future releases, including PKI support, LLVM compiler support, 32-bit RISC-V support, VIP-Bench benchmarks support, etc. Specification Version: 0.91 (October 2025) Contact: mojov-devs@umich.edu Current components Mojo-V ISA Spec v0.91 released in doc/ Spike (Instruction Set Simulator) Implementation Mojo-V integrated into riscv-isa-...