github-webhook-filter/lib/crypto.ts

38 lines
1.1 KiB
TypeScript

import config from "./config.ts";
import { hex } from "../deps.ts";
export const hasKey = !!config.signKey;
const encoder = new TextEncoder();
let _signKey: CryptoKey | undefined = undefined;
async function getKey(): Promise<CryptoKey> {
if (_signKey === undefined) {
if (!config.signKey) throw new Error("Signature requested but no key configured");
_signKey = await crypto.subtle.importKey(
"raw",
hex.decodeHex(config.signKey),
{ name: "HMAC", hash: "SHA-256" },
false,
["sign", "verify"],
);
}
return _signKey;
}
export async function sign(input: string): Promise<string> {
const key = await getKey();
const inputData = encoder.encode(input);
const sig = await crypto.subtle.sign("HMAC", key, inputData);
return hex.encodeHex(sig);
}
export async function verify(input: string, signature: string): Promise<boolean> {
const key = await getKey();
const inputData = encoder.encode(input);
const sig = hex.decodeHex(signature);
return await crypto.subtle.verify("HMAC", key, sig, inputData);
}