Structured Error Codes in Verifier

[AnkanMisra]

Problem

Currently, the verifier returns generic "invalid signature" errors. Debugging is impossible.

flowchart LR
    A[Signature] --> B{Verify}
    B -->|Fail| C["invalid signature"]
    
    style C fill:#f66

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Solution

Return specific error codes for each failure mode.

flowchart TD
    A[Signature] --> B{Parse Hex}
    B -->|Fail| E1["E002: Malformed signature"]
    B -->|Pass| C{Correct Length}
    C -->|Fail| E2["E002: Wrong length"]
    C -->|Pass| D{Recover Address}
    D -->|Fail| E3["E003: Recovery failed"]
    D -->|Pass| E{Match Expected}
    E -->|Fail| E4["E004: Address mismatch"]
    E -->|Pass| F["Valid"]
    
    style E1 fill:#f96
    style E2 fill:#f96
    style E3 fill:#f96
    style E4 fill:#f96
    style F fill:#6f6

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Error Code Reference

Code	Meaning	When
E001	Missing signature	No X-402-Signature header
E002	Malformed signature	Not hex, wrong length
E003	Recovery failed	crypto.Ecrecover failed
E004	Address mismatch	Recovered != expected
E005	Invalid message	Message format wrong
E006	Nonce reused	Duplicate nonce

Implementation

File: verifier/src/main.rs

#[derive(Serialize)]
struct VerifyError {
    code: String,
    message: String,
    details: Option<String>,
}

impl VerifyError {
    fn malformed_signature(details: &str) -> Self {
        Self {
            code: "E002".into(),
            message: "Malformed signature".into(),
            details: Some(details.into()),
        }
    }
}

Acceptance Criteria

• Define error code enum/constants
• Return structured JSON errors with codes
• Document all error codes in README
• Each error path has unique code
• Add tests for each error code
• Update OpenAPI spec with error responses

Testing

cd verifier && cargo test

[diksha78dev]

Hi, I am SWOC'26 contributor and i would like to work on this issue, can you assign this issue to me?

[AnkanMisra]

@Diksha78-bot Assigned