import { createVerify } from "crypto";
/**
* The structure of the data expected from an Agent.
*/
export interface AgentPayload {
message: string;
signature: string;
publicKey: string;
}
/**
* Result of a verification attempt.
*/
export interface VerificationResult {
isValid: boolean;
error?: string;
}
/**
* Verifies that a message was signed by the specific Agent Identity.
* Automatically handles common formatting issues (PEM headers, whitespace).
* * @param payload The object containing message, signature, and publicKey
* @returns VerificationResult { isValid: boolean, error?: string }
*/
export function verifyAgentIdentity(payload: AgentPayload): VerificationResult {
try {
const { message, signature, publicKey } = payload;
if (!message || !signature || !publicKey) {
return { isValid: false, error: "Missing required fields (message, signature, or publicKey)" };
}
// 1. Sanitize Signature (Remove non-hex characters like spaces/newlines)
const cleanSignature = signature.replace(/[^0-9a-fA-F]/g, '');
// 2. Sanitize Public Key (Ensure PEM headers exist)
let cleanKey = publicKey.trim();
// If user provided a raw key without headers, add them
if (!cleanKey.startsWith("-----BEGIN PUBLIC KEY-----")) {
cleanKey = `-----BEGIN PUBLIC KEY-----\n${cleanKey}\n-----END PUBLIC KEY-----`;
}
// 3. Perform Cryptographic Verification
const verify = createVerify("sha256");
verify.update(message);
verify.end();
const isValid = verify.verify(cleanKey, Buffer.from(cleanSignature, "hex"));
if (isValid) {
return { isValid: true };
} else {
return { isValid: false, error: "Signature mismatch. The message may have been tampered with." };
}
} catch (error: any) {
// Catch-all for malformed keys or other crypto errors
return { isValid: false, error: `Cryptographic error: ${error.message}` };
}
}
