Discussion on Move Language Security: Comprehensive Analysis of Features, Mechanisms, and Verification Tools

Preface

Move language, as a new generation smart contract language, is characterized mainly by its security. This article will explore the security issues of Move language from three aspects: language features, operating mechanisms, and verification tools.

1. The security features of the Move language

The Move language discards non-linear logic, does not support dynamic dispatch and recursive external calls, but instead uses concepts like generics, global storage, and resources to implement an alternative programming model. Below is a simple example of a token asset implementation:

move module 0x1::TestCoin { use 0x1::signer;

const ADMIN: address = @0x1;

struct Coin has key, store {
    value: u64
}

struct Info has key {
    total_supply: u64  
}

// The total supply is equal to the sum of the values of all Coins.
invariant forall addr: address where exists<coin>(addr):
    global<info>(ADMIN).total_supply == sum(select Coin.value (global<coin>(addr)));

public fun initialize(account: &signer) {
    assert!(signer::address_of(account) == ADMIN, 0);
    move_to(account, Info { total_supply: 0 });
}

public fun mint(account: &signer, amount: u64): Coin {
    assert!(signer::address_of(account) == ADMIN, 0);
    let supply = borrow_global_mut\u003cinfo\u003e(ADMIN);
    supply.total_supply = supply.total_supply + amount;  
    Coin { value: amount }
}

public fun value_mut(coin: &mut Coin): &mut u64 {
    &mut coin.value  
}

}

Two important security mechanisms of the Move language:

a) Invariant Check: Define state conservation through the reduction language.

b) Bytecode Verifier: Enforces safety types and linearization to prevent illegal operations.

2. The operating mechanism of Move

The Move program runs in a virtual machine and cannot directly access system memory. The program state consists of the call stack, memory, global variables, and the operation array.

MoveVM separates data storage and the call stack, improving security and execution efficiency. The independent storage of resources and strict access control effectively avoid some common vulnerabilities.

3. Move Prover

Move Prover is a formal verification tool that uses deductive verification algorithms to verify program correctness. Its architecture is as follows:

1. Receive Move source files and specifications
2. Compile to bytecode and validator object model
3. Convert to Boogie Intermediate Language
4. Generate Verification Conditions
5. Verify using Z3 solver
6. Output diagnostic report

Move Specification Language is used to describe the specifications of program behavior and can be written independently of business code.

4. Summary

The Move language has comprehensive security considerations in terms of language features, virtual machine execution, and security tools. It can effectively avoid some common vulnerabilities, but attention must still be paid to issues such as authentication and logic. Developers are advised to use third-party security audits and to have compliance verification carried out by professional security companies.