cl-crypto

AES-128, AES-192, and AES-256 ECB with PKCS5 padding for Node.js, matching Java Cipher#getInstance("AES/ECB/PKCS5Padding") where the key comes from SecretKeySpec(keyString.getBytes(UTF_8), "AES").

Requires Node.js 18+ (ES modules and node:crypto).

Install

Published package:

npm install cl-crypto

Local path dependency:

{
  "dependencies": {
    "cl-crypto": "file:../cl-crypto"
  }
}

Then:

npm install

The package exposes ESM and CommonJS via exports: import resolves to ESM, require to CJS.

Usage

ESM

import { encrypt, decrypt } from 'cl-crypto';

const key = '1234567890123456'; // 16 UTF‑8 bytes → AES-128
const ciphertext = encrypt('plain text', key);
const plaintext = decrypt(ciphertext, key);

CommonJS

const { encrypt, decrypt } = require('cl-crypto');

const key = '1234567890123456';
const ciphertext = encrypt('plain text', key);
const plaintext = decrypt(ciphertext, key);

API

encrypt(value, key)

• value — plaintext string (UTF‑8 bytes are encrypted).
• key — secret string interpreted as UTF‑8; length must be 16, 24, or 32 bytes (AES‑128, AES‑192, AES‑256).
• Returns — Base64 ciphertext.

decrypt(value, key)

• value — Base64 string produced by encrypt.
• key — same key as for encryption.
• Returns — plaintext string (UTF‑8 decoded).

Wrong key lengths throw: AES key must be 16, 24, or 32 bytes when UTF-8 encoded; got …

Java interoperability

Encrypt (conceptually the same pipeline as this package):

Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE,
    new SecretKeySpec(keyString.getBytes(StandardCharsets.UTF_8), "AES"));
byte[] ciphertext = cipher.doFinal(plaintextString.getBytes(StandardCharsets.UTF_8));
String base64 = Base64.getEncoder().encodeToString(ciphertext);

Decrypt:

Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE,
    new SecretKeySpec(keyString.getBytes(StandardCharsets.UTF_8), "AES"));
byte[] plain = cipher.doFinal(Base64.getDecoder().decode(base64Ciphertext));
String plaintext = new String(plain, StandardCharsets.UTF_8);

Use the same key string and UTF‑8 encoding on both sides.

Development

From the package root:

npm run validate

Rebuilds cjs/index.cjs from src/index.js (esbuild), then runs ESM and CJS smoke checks (scripts/validate.js and scripts/validate-cjs.cjs). After editing src/index.js, commit the regenerated cjs/index.cjs or run npm run build:cjs before publish.

Security

ECB does not use an IV; repeated plaintext blocks produce repeated ciphertext. Prefer AES‑GCM (or similar) for new systems. This package is for compatibility with existing ECB‑based integrations.

License

MIT