ClassyX403 Protocol

Comprehensive technical documentation for implementing policy-native execution control on Solana.

Introduction

ClassyX403 is a policy-native execution layer for Solana that introduces deterministic, pre-execution access control for high-value programs, AI agents, and institutional workflows.

The protocol operates as a transparent intermediary layer, evaluating policy compliance before allowing transactions to reach their target programs. This approach ensures that access control is enforced consistently and deterministically across all execution contexts.

Unlike traditional access control mechanisms that are embedded within individual programs, ClassyX403 provides a protocol-level solution that can be composed across multiple programs and use cases without modifying existing program logic.

Core Concepts

Policy-Native Architecture

ClassyX403 treats policies as first-class citizens in the execution flow. Every transaction must satisfy policy requirements before execution proceeds. This model ensures that access control is not an afterthought but a foundational component of the execution process.

Deterministic Evaluation

Policy evaluation outcomes are deterministic and predictable. Given the same transaction inputs and policy state, the result will always be consistent. This property is critical for institutional use cases where execution certainty is required.

Pre-Execution Enforcement

Unlike post-execution validation, ClassyX403 evaluates and enforces policies before state mutation occurs. This approach prevents invalid transactions from consuming resources and ensures that failed policy checks do not result in partial state changes.

Policy Program

The ClassyX403 policy program is a Solana program that manages policy definitions, evaluates transaction requests, and enforces access control decisions.

Policy StructureRust

pub struct Policy {
    pub authority: Pubkey,
    pub target_program: Pubkey,
    pub rules: Vec<PolicyRule>,
    pub bump: u8,
}

Each policy is defined by an authority (typically a multisig or governance program), a target program that the policy applies to, and a set of rules that define allowed operations.

Policy Accounts (PDAs)

Policy accounts are implemented as Program Derived Addresses (PDAs) to ensure deterministic addressing and safe concurrent access.

PDA DerivationRust

let (policy_pda, bump) = Pubkey::find_program_address(
    &[
        b"policy",
        authority.as_ref(),
        target_program.as_ref(),
    ],
    &program_id,
);

PDA-based policy accounts enable parallel execution without conflicts, as each policy has a unique, deterministically-derived address based on its authority and target program.

Execution Lifecycle

The ClassyX403 execution lifecycle consists of several distinct phases that ensure secure and deterministic policy enforcement.

Transaction Submission

Client Side

Client submits a transaction that includes a CPI to the ClassyX403 policy program before calling the target program. The transaction contains all necessary accounts and instruction data.

Policy Evaluation

Protocol Layer

ClassyX403 loads the relevant policy account and evaluates the transaction against defined rules. Evaluation is deterministic and based on on-chain state, ensuring consistent outcomes.

Authorization Decision

Policy Check

If policy checks pass, execution continues to the target program. If checks fail, the transaction reverts before any state mutation occurs, ensuring security and preventing partial updates.

Target Execution

Final Step

Only after successful policy validation does the transaction proceed to the target program, ensuring authorized execution with full security guarantees and audit trail.

Security Model

ClassyX403's security model is designed to provide defense-in-depth protection for high-value operations.

Immutable Policy Logic

Policy evaluation logic is immutable and verifiable on-chain, preventing tampering or manipulation.

Authority Verification

All policy modifications require signature from the designated authority, typically a multisig or governance program.

CPI Safety

PDA-based policies ensure that cross-program invocations cannot bypass policy checks or manipulate policy state.

Parallel Execution Safety

Deterministic PDA addressing ensures that concurrent transactions do not conflict, enabling safe parallel execution.

Solana-Specific Design

ClassyX403 is purpose-built for Solana's execution model, leveraging unique features of the Solana runtime to deliver optimal performance and security.

Account Model Optimization

Solana's account model allows ClassyX403 to store policy state in dedicated accounts, enabling efficient lookups and minimal computational overhead during evaluation.

Sealevel Runtime Integration

ClassyX403 integrates seamlessly with Solana's Sealevel runtime, ensuring that policy checks occur within the same transaction context as the protected operation.

Rent-Exempt Policies

All policy accounts are initialized as rent-exempt, ensuring long-term availability without ongoing maintenance costs.