Summary: Move (Sui/Aptos) prevents entire classes of EVM-era failures by design—resource types, strict abilities, bytecode verification, and formal specs—while still supporting enterprise-grade upgrade and governance patterns. Below, we translate those technical guarantees into procurement-ready outcomes: fewer audit cycles, lower breach probability, and faster go-live under SOC2-driven SDLC.

Title: Move Language (Sui/Aptos): Security Advantages Over Solidity

Audience: Enterprise CTO/CISO and Procurement

Pain — “We just passed audit, why are we still reopening criticals?”

• On EVM, even with Solidity ≥0.8’s checked arithmetic, teams still inherit footguns: delegatecall-based proxy pitfalls, storage layout collisions, fragile upgrade paths, and reentrancy edge-cases that reappear via new patterns. These keep delaying sign-offs and racking up audit iterations. (soliditylang.org)
• Real-world cost: a single reentrancy on Curve’s pools in July 2023 drained ~$60M—despite industry maturity and monitoring. Every reopened critical or rushed hotfix becomes a board conversation about risk posture and budget. (blog.sui.io)
• Proxies reduce redeploy costs but introduce storage-collision risks if layout discipline slips; EIP‑1967 standardizes slots for implementation/admin, yet many incidents still stem from deviations during upgrades. Miss one migration note, and you can brick an upgrade or expose admin. (eips.ethereum.org)

Agitation — Where this bites delivery dates (and SOC2)

• “One more audit pass” becomes three: reentrancy guards across modules, proxy initializer gaps, and storage collisions force last-mile rework—often in the handoff from engineering to compliance. Each extra cycle means burn on security vendors and SRE time; your SOC2 evidence pack grows but confidence doesn’t. (docs.soliditylang.org)
• Dependencies drift: A mispinned library reintroduces a previously fixed class of bugs. Without deterministic dependency locks and formal specs in CI, your QA can pass and production still diverges. Procurement sees that as process immaturity, not just “dev speed.”
• User onboarding friction: on EVM you can’t natively sponsor gas safely at scale; on Sui, native sponsored transactions reduce friction—but introduce equivocation risks if you don’t design gas stations and rate limits correctly. Poorly handled, a malicious client can lock your gas objects until epoch end, freezing operations. That’s a KPI outage, not a developer curiosity. (docs.sui.io)

Solution — Why Move (Sui/Aptos) reduces classes of bugs by construction

1. Resource-oriented safety and “abilities” eliminate phantom asset states

• Assets are linear “resources,” not integers in a map. The type system enforces conservation: no copy, no implicit drop, explicit move-only semantics, gated by abilities: key, store, copy, drop. For asset-like types, you simply don’t grant copy/drop, and the compiler/VM refuses unsafe flows. This removes a whole stratum of ERC-20/721 mishaps. (move-language.github.io)

1. Capability-based access control, not ad‑hoc address checks

• Privilege is represented as a typed capability (e.g., AdminCap). Only holders can call privileged flows; module boundaries plus friend/package visibility prevent “creative” external calls from bypassing intent. This aligns with least-privilege and cuts the surface area for access-control bugs. (aptos.dev)

1. Verified bytecode and “paranoid mode”

• Move VM rejects malformed or unsafe bytecode at load time; Aptos additionally supports “paranoid” runtime re-verification to double-check safety invariants. The combination catches classes of issues earlier than EVM’s source verification model. (aptos.dev)
• Reality check: even verifiers can have bugs; the Zellic “billion-dollar Move bug” disclosure led to swift patches across forks. The takeaway for enterprises: Move’s hardening and transparency (plus our audit practice) yield a faster “defect-to-fix” cycle than ad-hoc EVM defenses. (zellic.io)

1. Formal specifications in CI, with exhaustive proofs

• Move Prover + MSL lets us encode business invariants—conservation, access, abort conditions—and prove them across all inputs and states. We wire prover gates into CI, blocking merges when specs break. This maps cleanly to SOC2 change control and “secure-by-default” SDLC. (aptos.dev)

1. Reentrancy: stronger defaults, explicit control in Aptos 2.2, and constrained patterns on Sui

• Historically, Move had no reentrancy. Aptos Move 2.2 added first-class “function values,” enabling controlled reentrancy via callbacks; the VM detects reentry and locks module resources during re-entry, aborting unsafe access. Sensitive entrypoints can add #[module_lock] to hard-block reentrancy via closures. Net: modern patterns without EVM-style surprise recursion. (aptos.dev)
• Sui’s variant focuses on object-centric concurrency; with no function values today, reentrancy via dynamic callbacks isn’t a norm. Instead, the object/versioning model and PTB atomicity address double-spend classes and stale-state hazards at the storage layer. (docs.sui.io)

1. Sui object model: versioned objects, locks, and atomic PTBs

• Every object has a unique ID and monotonically increasing version. Validators lock objects during validation; if you equivocate (submit conflicting transactions with the same version), the object is locked until epoch end—preventing double-spends at the protocol level. (docs.sui.io)
• Programmable Transaction Blocks bundle up to 1,024 commands and apply effects atomically; partial success is impossible. That’s a practical guardrail against half-applied business flows. (docs.sui.io)

1. Governed upgrades with explicit compatibility policies

• Aptos: package-level upgrades with compatibility checking enforced by the VM prevent breaking storage layouts and public APIs. Policy lives in Move.toml; incompatible publishes abort. Enterprises get deterministic deploys and safer hotfixes. (aptos.dev)
• Sui: UpgradeCap + UpgradeTicket define who can upgrade, what can change, and enforce single-transaction authorization→upgrade→commit. Policies (immutable, dependency-only, additive, compatible) can only become more restrictive over time—a governance feature auditors appreciate. (docs.sui.io)

1. Enterprise onboarding UX without sacrificing control

• Native sponsored transactions on Sui allow “no gas wallet” onboarding; we design gas stations with two-party signatures, rate limits, and monitoring to mitigate equivocation and censorship risks outlined in the official docs. This trims funnel drop-off without compliance surprises. (docs.sui.io)

Practical examples you can ship (and prove)

A) Asset that can’t be copied or silently dropped (Sui/Aptos Move)

module 0xACME::vault {
    use std::error;
    use std::signer;

    // No copy/drop — enforces conservation at the type level
    struct Vault has key, store {
        balance: u64
    }

    // Capability for privileged ops (e.g., mint)
    struct AdminCap has key, store { id: u64 }

    public(friend) fun mint(_cap: &AdminCap, to: address, amount: u64) {
        if (!exists<Vault>(to)) {
            move_to(&signer::address_of(&signer::new_signer(to)), Vault { balance: 0 });
        };
        let v = borrow_global_mut<Vault>(to);
        v.balance = v.balance + amount;
    }

    public fun transfer(from: &signer, to: address, amount: u64) acquires Vault {
        let vf = borrow_global_mut<Vault>(signer::address_of(from));
        assert!(vf.balance >= amount, error::invalid_argument(1));
        let vt = borrow_global_mut<Vault>(to);
        vf.balance = vf.balance - amount;
        vt.balance = vt.balance + amount;
    }

    spec module {
        // Invariant: global sum of balances changes only via mint with AdminCap
    }

    spec transfer {
        aborts_if !exists<Vault>(signer::address_of(from));
        aborts_if !exists<Vault>(to);
        aborts_if borrow_global<Vault>(signer::address_of(from)).balance < amount;
        ensures borrow_global<Vault>(signer::address_of(from)).balance
                == old(borrow_global<Vault>(signer::address_of(from))).balance - amount;
        ensures borrow_global<Vault>(to).balance
                == old(borrow_global<Vault>(to)).balance + amount;
    }
}

• What this buys you: the type system enforces non-copyable assets; “friend” confines minting; MSL specs are machine-checked in CI so regressions fail fast. (move-language.github.io)

B) Aptos Move 2.2: callback pattern with explicit reentrancy guard

module 0xACME::escrow {
    use std::signer;

    struct State has key { locked: bool, amount: u64 }

    #[module_lock] // block closure-based reentrancy into this module
    public fun release(user: &signer, mut s: State, cb: ||()) acquires State {
        assert!(!s.locked, 1001);
        s.locked = true;
        cb(); // if this tries to call back into escrow and touch State, VM aborts
        s.locked = false;
    }
}

• The VM locks module resources on reentry; #[module_lock] elevates guarantees for sensitive paths. This is not a “best effort” pattern—it’s enforced by the runtime. (aptos.dev)

C) Sui PTB for atomic multi-step operations with a sponsored gas coin

// TypeScript (Sui SDK): build one atomic PTB
import { Transaction } from '@mysten/sui/transactions';
const tx = new Transaction();

// Use sponsor-provided gas object; insert business calls
const [coin] = tx.splitCoins(tx.gas, [tx.pure.u64(100_000)]);
tx.transferObjects([coin], tx.pure.address('0x<recipient>'));

// Both user and sponsor must sign the same TransactionData; monitor equivocation risks.

• Effect: a multi-call “macro” either fully applies or fully rolls back; with sponsorship, wallets don’t need SUI to start. Design in rate limits and duplicate-submission detection to avoid locks. (docs.sui.io)

Emerging best practices (2025–2026) we implement for you

• Aptos Move 2.2 reentrancy discipline
  • Use #[module_lock] on any entry that accepts function values (callbacks).
  • Treat all closure dispatch as untrusted; design state reservations upfront (borrow before call, mutate after). (aptos.dev)
• Sui object and upgrade hygiene
  • Restrict UpgradeCap early (only_additive_upgrades or dep_only) before TVL accrues; make immutable once feature-complete. Enforce upgrade authorization via governance policies issuing UpgradeTickets per change. (docs.sui.io)
  • Keep Move.lock committed to repo to pin chain-published addresses and dependency versions; rely on Sui’s automated address management post v1.29.0. (docs.sui.io)
• Capability and visibility choices
  • Prefer capability gates plus friend/package visibility over address-based modifiers; this minimizes “accidentally public” mistakes that audits regularly catch. (aptos.dev)
• Formal specs in CI, not afterthoughts
  • Use aborts_if_is_strict, enumerated abort codes, and global invariants; Move Prover runs on PRs and blocks merges on spec drift. (aptos.dev)
• Sponsored transactions at scale
  • Force dual signatures on TransactionData including GasData; implement rate limits, and alert on equivocation to avoid epoch-long locks. Ship dashboards to trace locked objects. (docs.sui.io)
• Verified artifacts for auditors and procurement
  • Use Sui Explorer’s source-verified packages for framework references; produce SBOM-like dependency manifests and upgrade policies as evidence. (blog.sui.io)

How this maps to business outcomes (ROI + SOC2)

• Fewer audit cycles: formal specifications and bytecode verification eliminate whole bug classes pre-audit, lowering triage churn and “reopen” risk. The OWASP Smart Contract Top 10 shifts from “fix” to “prove absent.” (owasp.org)
• Lower breach probability: reentrancy is constrained by runtime semantics (Aptos) or architecture (Sui). Storage layout breaks are curbed via package compatibility policies instead of fragile proxy slots. (aptos.dev)
• Faster go-live under SOC2: prover logs, policy locks (UpgradeCap/Move.toml), and Move.lock provide change-management evidence and deterministic rollouts—clean artifacts for auditors and vendor risk teams. (docs.sui.io)
• Lower onboarding friction: sponsored transactions reduce token top-up support load. With proper controls, you keep abuse in check and NPS intact. (docs.sui.io)

7Block Labs methodology: technical but pragmatic

• Architecture and chain fit
  • We recommend Sui when object-centric concurrency and PTBs deliver operational advantages (e.g., asset logistics, marketplaces), and Aptos when you need modern language features (function values) with module locks for controlled extensibility.
• Spec-first development
  • We draft invariants with you, encode them in MSL, and wire aptos move prove / sui move test into CI. Break a spec? The PR won’t merge. (aptos.dev)
• Upgrade and governance design
  • On Sui, we deploy UpgradeCap policies (timelocks, quorum-based UpgradeTicket issuers); on Aptos, we set explicit “compatible” policies and publish guards. (docs.sui.io)
• Secure onboarding
  • Gas stations with observable rate limits, dual signatures on TransactionData/GasData, and alerts for equivocation side-effects. We also document response playbooks aligned to SOC2 CC series controls. (docs.sui.io)
• Independent verification
  • We combine formal proofs, fuzzing, and third-party audits; we monitor upstream language/runtime advisories (e.g., Move verifier fixes, Aptos paranoid mode) and backport mitigations. (zellic.io)

GTM metrics we deliver and report during a 90‑day pilot

• Security engineering KPIs
  • Spec coverage: ≥80% of public/entry functions with MSL specs and enumerated abort codes; CI hard-gates on prover pass/fail. (aptos.dev)
  • Zero “Critical/High” findings at Release Candidate from external auditors; deltas closed <7 days with proof artifacts.
  • Reentrancy posture: 100% of callback-accepting functions guarded by #[module_lock] (Aptos) or disallowed pattern (Sui). (aptos.dev)
• SDLC/Compliance KPIs (SOC2-ready)
  • Deterministic builds: Move.lock and signed release manifests for every environment.
  • Upgrade policies enforced: “additive” or stricter before TVL; immutable at GA unless governance requires otherwise. Evidence retained. (docs.sui.io)
• Product/Operations KPIs
  • Time-to-first-transaction (TTFT) under sponsored model: p50 <10s with no-wallet users; locked-object rate <0.1% with alerting and auto-rescue at epoch change. (docs.sui.io)

EVM migration notes for enterprise stacks

• Upgrades: if you retain EVM-side components, follow ERC‑1967/UUPS exactly; freeze storage layout, and treat initializer patterns as compliance items with unit tests and static checks. Move-side packages take over as “source of truth” for asset logic, reducing delegatecall exposure. (eips.ethereum.org)
• Formal verification maturity: Solidity’s SMTChecker exists, but Move’s MSL + Prover natively aligns with the language’s linear resource semantics, producing clearer, less brittle proofs for asset invariants. Keep EVM glue thin. (docs.solidity.org)

What you get with 7Block Labs

• End-to-end Move build-out with compliance artifacts
  • Our smart contract development and custom blockchain development services ship with prover configs, CI gates, and upgrade governance.
• Security-first delivery
  • Independent security audit services plus formal specs; we design sponsored gas safely and wire operational runbooks.
• Ecosystem integration and expansion
  • Cross-domain needs? Our blockchain integration and cross-chain solutions development keep EVM-facing pieces minimal and verifiable.
• Commercialization support
  • If your pilot demonstrates traction, we support fundraising and tokenization paths with asset tokenization and web3 development services.

Appendix: precise references to validate claims

• OWASP Smart Contract Top 10 and evolving risk categories (2023→2025). (owasp.org)
• Solidity arithmetic checks (≥0.8), and why proxy/storage discipline still fails in practice. (soliditylang.org)
• ERC‑1967 storage slot standard for proxies (collision avoidance). (eips.ethereum.org)
• Move Prover and MSL, with exhaustive verification and abort semantics. (aptos.dev)
• Aptos Move 2.2 reentrancy model, runtime module locks, and #[module_lock]. (aptos.dev)
• Sui object versioning, equivocation, epochs, and PTB atomicity. (docs.sui.io)
• Sui UpgradeCap policies and upgrade flow; governance patterns via UpgradeTicket/Receipt. (docs.sui.io)
• Aptos package upgrades and compatibility enforcement. (aptos.dev)
• Verified sources and dependency locking for auditability (Sui Explorer, Move.lock). (blog.sui.io)
• Move bytecode verifier hardening and historical fixes (Zellic). (zellic.io)

If you’re weighing Solidity vs Move for an enterprise-grade rollout, the question isn’t “can we make EVM safe?” It’s “how many problem classes do we want to eliminate upfront, and how quickly can we prove that to auditors?”

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