chore: add TOTP encryption key rotation script

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/rotate-totp-key.ts

@@ -0,0 +1,71 @@
+import crypto from 'crypto';
+import { PrismaClient } from '@prisma/client';
+
+const prisma = new PrismaClient();
+
+function decrypt(ciphertext: string, keyHex: string): string {
+  const key = Buffer.from(keyHex, 'hex');
+  const [ivHex, encHex, tagHex] = ciphertext.split(':');
+  const iv = Buffer.from(ivHex, 'hex');
+  const encrypted = Buffer.from(encHex, 'hex');
+  const tag = Buffer.from(tagHex, 'hex');
+  const decipher = crypto.createDecipheriv('aes-256-gcm', key, iv);
+  decipher.setAuthTag(tag);
+  return decipher.update(encrypted, undefined, 'utf8') + decipher.final('utf8');
+}
+
+function encrypt(plaintext: string, keyHex: string): string {
+  const key = Buffer.from(keyHex, 'hex');
+  const iv = crypto.randomBytes(12);
+  const cipher = crypto.createCipheriv('aes-256-gcm', key, iv);
+  const encrypted = Buffer.concat([cipher.update(plaintext, 'utf8'), cipher.final()]);
+  const tag = cipher.getAuthTag();
+  return `${iv.toString('hex')}:${encrypted.toString('hex')}:${tag.toString('hex')}`;
+}
+
+async function main() {
+  const oldKey = process.argv[2];
+  const newKey = process.argv[3];
+  const dryRun = process.argv.includes('--dry-run');
+
+  if (!oldKey || !newKey) {
+    console.error('Usage: tsx scripts/rotate-totp-key.ts <old-key-hex> <new-key-hex> [--dry-run]');
+    process.exit(1);
+  }
+
+  const users = await prisma.users.findMany({
+    where: { totp_enabled: true, totp_secret: { not: null } },
+    select: { id: true, username: true, totp_secret: true },
+  });
+
+  console.log(`Found ${users.length} users with TOTP enabled`);
+
+  if (dryRun) {
+    for (const user of users) {
+      try {
+        const decrypted = decrypt(user.totp_secret!, oldKey);
+        const reEncrypted = encrypt(decrypted, newKey);
+        decrypt(reEncrypted, newKey); // verify round-trip
+        console.log(`  [OK] ${user.username} (id=${user.id}) — decryption and re-encryption verified`);
+      } catch (e) {
+        console.error(`  [FAIL] ${user.username} (id=${user.id}) — ${e}`);
+      }
+    }
+    console.log('\nDry run complete. No changes made.');
+    return;
+  }
+
+  await prisma.$transaction(async (tx) => {
+    for (const user of users) {
+      const decrypted = decrypt(user.totp_secret!, oldKey);
+      const reEncrypted = encrypt(decrypted, newKey);
+      await tx.users.update({ where: { id: user.id }, data: { totp_secret: reEncrypted } });
+      console.log(`  Re-encrypted TOTP for ${user.username} (id=${user.id})`);
+    }
+  });
+
+  console.log('\nAll TOTP secrets re-encrypted successfully.');
+  await prisma.$disconnect();
+}
+
+main().catch((e) => { console.error(e); process.exit(1); });