Formal Verification

Traditional smart contract auditing relies on manual code reviews and dynamic fuzzing tests. While necessary, fuzzing cannot test all $2^{64}$ possible input states of an invariant engine.

u64se-seu-solana achieves mathematical proof of correctness through Formal Verification via Satisfiability Modulo Theories (SMT) using Microsoft Research’s Z3 solver.

The QF_BV SMT Logic

All 15 safety and block-ordering invariants are codified into SMT-LIB2 format under the Quantifier-Free Bit-Vector Theory (QF_BV).

Under QF_BV:

• All variables are modeled as exact bit-vectors: (_ BitVec 8), (_ BitVec 16), (_ BitVec 64).
• Operations are bit-exact hardware primitives: bvand, bvor, bvadd, bvsub, bvlshr.
• The solver searches the entire state space of $2^{64}$ bit combinations to find any counter-example where a safety violation occurs while fault == 0.

When Z3 returns unsat for a theorem, it is a formal mathematical guarantee that no input state exists in the universe that can bypass the safety invariant.