54 lines
2.3 KiB
TypeScript
54 lines
2.3 KiB
TypeScript
// Encryption at rest for order data (Shopify protected customer data, Level 1).
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// - hashId(): keyed HMAC-SHA256, deterministic, so order ids can still be counted and de-duplicated
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// without storing them readably.
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// - encrypt()/decrypt(): AES-256-GCM for values we need to show again (order number, order id for links).
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// Key: DATA_ENCRYPTION_KEY = 64 hex characters (openssl rand -hex 32). Keep it out of Git; losing it makes
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// existing analytics rows unreadable (they still count).
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import { createCipheriv, createDecipheriv, createHash, createHmac, randomBytes } from "node:crypto";
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let keys: { enc: Buffer; mac: Buffer } | null = null;
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/** Fails fast at startup: a bad key would otherwise only surface as 500s on every orders/create webhook. */
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export function assertEncryptionKey() {
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getKeys();
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}
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function getKeys() {
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if (keys) return keys;
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const hex = process.env.DATA_ENCRYPTION_KEY || "";
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if (!/^[0-9a-fA-F]{64}$/.test(hex)) {
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throw new Error("DATA_ENCRYPTION_KEY must be 64 hex characters (openssl rand -hex 32)");
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}
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const master = Buffer.from(hex, "hex");
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keys = {
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enc: createHash("sha256").update(Buffer.concat([master, Buffer.from("offerlyst:enc:v1")])).digest(),
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mac: createHash("sha256").update(Buffer.concat([master, Buffer.from("offerlyst:mac:v1")])).digest(),
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};
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return keys;
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}
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export function hashId(value: string) {
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return createHmac("sha256", getKeys().mac).update(value).digest("hex");
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}
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export function encrypt(value: string | null | undefined): string | null {
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if (value == null || value === "") return null;
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const iv = randomBytes(12);
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const cipher = createCipheriv("aes-256-gcm", getKeys().enc, iv);
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const data = Buffer.concat([cipher.update(value, "utf8"), cipher.final()]);
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return `v1:${Buffer.concat([iv, cipher.getAuthTag(), data]).toString("base64")}`;
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}
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export function decrypt(value: string | null | undefined): string | null {
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if (!value) return null;
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if (!value.startsWith("v1:")) return value; // not encrypted (should not happen)
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try {
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const raw = Buffer.from(value.slice(3), "base64");
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const decipher = createDecipheriv("aes-256-gcm", getKeys().enc, raw.subarray(0, 12));
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decipher.setAuthTag(raw.subarray(12, 28));
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return Buffer.concat([decipher.update(raw.subarray(28)), decipher.final()]).toString("utf8");
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} catch {
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return null;
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}
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}
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