Mojo-V: Secret Computation for RISC-V (github.com)

Mojo‑V (pronounced “mojo‑five”) is a new RISC‑V ISA extension that introduces hardware‑enforced secret computation: dedicated secret registers, memory encrypted under a third‑party key, and compute semantics that are both blind (no direct data disclosures) and silent (designed to prevent side‑channel leakage). The design is minimally invasive—one mode bit and four new instructions, enforcement at decode—and the reference release (Spec v0.91, Oct 2025) already implements 64‑bit secret integer and floating‑point operations using a fixed symmetric cipher (Simon‑128). Mojo‑V is integrated into Spike (riscv‑isa‑sim) and comes with hand‑coded bringup benchmarks and a 375‑test security suite; run Spike with --isa=rv64gc_zicond_zkmojov_zicntr. Significance: Mojo‑V offers a practical path to hardware‑level confidential computation without relying on fragile software abstractions or fully homomorphic encryption (FHE). Early results report near‑native execution speed and a 5–7 orders‑of‑magnitude performance improvement versus FHE, making many secure, data‑oblivious workloads (cloud enclaves, secure accelerators, privacy‑preserving analytics) feasible in practice. Caveats: current platform uses fixed keys (no PKI yet), many benchmarks are hand‑ported assembly, and broader toolchain support (LLVM, 32‑bit, PKI) is on the roadmap. The project is open for contributions, red‑teaming, and integration into CPUs, GPUs, and accelerators.