Divergent Multi-Version Execution: Per-Instruction Full-State Hashing with Address-Space Decorrelation

Version 1. 1 (Revised and expanded) This version introduces several improvements to the original DME paper: - Reformulated Diversity Divergence Theorem with explicit three-part structure and probabilistic bound P ≤ (ρL/R) ^N-1- Added Assumption 2. 2 (Replica-Private Address Spaces) to strengthen fault model- Clarified memory footprint: 512 bytes per replica covers CPU context + hash state only (stack/heap allocated separately) - Added Listing 1 with per-replica execution loop showing fetch-execute-hash-compare cycle- Added note that while tested in virtualised environment, DME can be implemented natively in assembly on physical hardware- Minor corrections and formatting improvements Original abstract: Redundancy-based fault tolerance techniques typically execute identical binaries with identical address layouts, leaving systems vulnerable to correlated control-flow faults. This paper introduces Divergent Multi-Version Execution (DME), which combines address-space decorrelation with per-instruction full-state hashing. Identical instruction bytes are preserved across replicas, while basic blocks are mapped to distinct addresses. After each instruction, replicas compute incremental state hashes and perform synchronous comparison.