release: WRNexusJS 0.4.0

packages/encryption/src/index.ts

@@ -138,3 +138,5 @@ export async function deriveKey(password: string, salt: string): Promise<string>
   );
   return toB64(new Uint8Array(bits));
 }
+export { createKeyring, seal, open, sealedKeyId, needsRotation } from "./keyring.ts";
+export type { EncryptionKey, EncryptionKeyring } from "./keyring.ts";

packages/encryption/src/keyring.ts

@@ -0,0 +1,101 @@
+import { decrypt, encrypt, generateKey } from "./index.ts";
+
+export interface EncryptionKey {
+  id: string;
+  secret: string;
+  active?: boolean;
+  createdAt?: number;
+}
+
+export interface EncryptionKeyring {
+  active(): EncryptionKey;
+  get(id: string): EncryptionKey | undefined;
+  keys(): EncryptionKey[];
+  rotate(key?: EncryptionKey): Promise<EncryptionKey>;
+  remove(id: string): boolean;
+}
+
+const KEY_ID = /^[A-Za-z0-9._-]{1,64}$/;
+
+function validateKey(key: EncryptionKey): void {
+  if (!KEY_ID.test(key.id)) {
+    throw new TypeError(`Invalid encryption key id: ${key.id}`);
+  }
+  if (!key.secret.trim()) {
+    throw new TypeError(`Encryption key '${key.id}' has an empty secret`);
+  }
+}
+
+export function createKeyring(initial: EncryptionKey[]): EncryptionKeyring {
+  const values = new Map<string, EncryptionKey>();
+  let activeCount = 0;
+  for (const key of initial) {
+    validateKey(key);
+    if (values.has(key.id)) {
+      throw new Error(`WRN-ENCRYPTION-KEYRING-DUPLICATE: ${key.id}`);
+    }
+    if (key.active) activeCount++;
+    values.set(key.id, { ...key });
+  }
+  if (!values.size) throw new Error("WRN-ENCRYPTION-KEYRING-EMPTY");
+  if (activeCount > 1) throw new Error("WRN-ENCRYPTION-KEYRING-MULTIPLE-ACTIVE");
+
+  const activeInternal = (): EncryptionKey => {
+    const key = [...values.values()].find((entry) => entry.active) ?? [...values.values()].at(-1);
+    if (!key) throw new Error("WRN-ENCRYPTION-ACTIVE-KEY-MISSING");
+    return key;
+  };
+
+  return {
+    active: () => ({ ...activeInternal() }),
+    get(id) {
+      const key = values.get(id);
+      return key ? { ...key } : undefined;
+    },
+    keys: () => [...values.values()].map((key) => ({ ...key })),
+    async rotate(key) {
+      const next = key ?? {
+        id: `key-${Date.now().toString(36)}`,
+        secret: await generateKey(),
+        createdAt: Date.now(),
+      };
+      validateKey(next);
+      for (const current of values.values()) current.active = false;
+      const stored = { ...next, active: true };
+      values.set(stored.id, stored);
+      return { ...stored };
+    },
+    remove(id) {
+      if (!values.has(id)) return false;
+      if (values.size <= 1) {
+        throw new Error("WRN-ENCRYPTION-KEYRING-LAST-KEY");
+      }
+      if (activeInternal().id === id) {
+        throw new Error("WRN-ENCRYPTION-KEYRING-ACTIVE-REMOVE");
+      }
+      return values.delete(id);
+    },
+  };
+}
+
+/** Versioned payload: `wrn1.<key-id>.<aes-gcm-payload>`. */
+export async function seal(plaintext: string, keyring: EncryptionKeyring): Promise<string> {
+  const key = keyring.active();
+  return `wrn1.${key.id}.${await encrypt(plaintext, key.secret)}`;
+}
+
+export async function open(sealed: string, keyring: EncryptionKeyring): Promise<string> {
+  const match = /^wrn1\.([A-Za-z0-9._-]{1,64})\.(.+)$/.exec(sealed);
+  if (!match) throw new Error("WRN-ENCRYPTION-PAYLOAD-VERSION");
+  const key = keyring.get(match[1]!);
+  if (!key) throw new Error(`WRN-ENCRYPTION-KEY-NOT-FOUND: ${match[1]}`);
+  return decrypt(match[2]!, key.secret);
+}
+
+export function sealedKeyId(sealed: string): string | null {
+  return /^wrn1\.([A-Za-z0-9._-]{1,64})\./.exec(sealed)?.[1] ?? null;
+}
+
+export function needsRotation(sealed: string, keyring: EncryptionKeyring): boolean {
+  return sealedKeyId(sealed) !== keyring.active().id;
+}