jjspassende is a high‑performance, multi‑pattern cryptographic library for JavaScript (Node.js) that goes far beyond standard encryption. It offers 14 unique patterns spanning AEAD, stream ciphers, block ciphers, and key derivation – all wrapped in a simple, consistent API. Every pattern uses its own distinct combination of algorithms and constructions, making your ciphertext immediately recognisable and self‑describing.

It is a faithful JavaScript port of the Python jpassende library: packages produced by one are decodable by the other (same key), because both use the same wire format, algorithms, and key‑derivation parameters.

---

Quick Start – Encrypt & Decrypt in Two Lines

const { JPassende } = require('jjspassende');

const jp = new JPassende();

const result = jp.encode("Hello, World!", "vail", "my_secret");
console.log(result.encoded); // base85-encoded package (string)

const original = jp.decode(result.encoded, "vail", "my_secret");
console.log(original.decoded); // 'Hello, World!'

encode() returns a CryptoResult ({ encoded, pattern, layer, needsKey, elapsed, timestamp }) and decode() returns a DecodeResult ({ decoded, pattern, layer, verified, elapsed }) – mirroring the Python CryptoResult / DecodeResult dataclasses. Pass result.encoded (not result itself) into decode().

---

Main Capabilities

· AEAD Patterns – vail (AES‑256‑GCM), phnx (ChaCha20‑Poly1305), nixl (ChaCha20 + independent BLAKE2‑based HMAC). All three provide authenticated encryption with associated data (AAD) support.

· Stream Patterns – strx (BLAKE2‑based keystream), rvrs (SHA‑3 feedback mode), lfsr (dual‑state SHA‑3 / BLAKE2 generator). Byte‑by‑byte encryption without padding, ideal for streaming data.

· Block Patterns – aegs (AES‑CTR + HMAC), cblk (AES‑CBC + HMAC), cfbb (AES‑CFB‑128 + HMAC), ofbb (AES‑OFB + HMAC). Standard block cipher modes, each individually authenticated.

· Derivation Patterns – hkdf (HMAC‑based Extract‑and‑Expand), scrt (scrypt), pbk2 (PBKDF2‑SHA‑512), blk3 (Merkle‑tree commitment). Password hashing, key material generation, and data integrity commitments.

· Security Layers – Every pattern supports three selectable security layers: STANDARD (300k PBKDF2 iterations), FORTIFIED (600k), and QUANTUM (1.2M). You control the trade‑off between speed and brute‑force resistance.

· Binary & Text I/O – options.outputRaw returns a Buffer instead of a base‑encoded string. options.inputRaw accepts raw bytes (Buffer) directly, so you can encrypt binary files, images, or any byte sequence.

· Cross‑Instance / Cross‑Language Decryption – Packages carry all the metadata (magic, version, pattern ID, salt, nonce) needed for decryption. Any JPassende instance – JavaScript or Python – can decrypt, provided it has the same key.

· Self‑Describing Packages – The binary format includes a magic header, version byte, pattern identifier, and optional AAD. No more guessing which algorithm was used.

· LRU Key Cache – PBKDF2 derivations are cached (simple Map-based LRU) to avoid redundant work when the same password is reused.

· Invalid Package Detection – A dedicated InvalidPackageError is raised when the package structure, magic, or version is invalid.

· Zero Plaintext Password Storage – Cache keys are derived from a BLAKE2b hash of (password + salt + parameters), never from the password itself.

---

Pattern Status

The patterns nixl, strx, rvrs, lfsr, aegs, cblk, cfbb, ofbb, hkdf, scrt, pbk2, and blk3 are custom constructions created exclusively for jjspassende/jpassende. They are currently experimental and under active development – their internal design may evolve as we gather feedback and perform further security analysis. The patterns vail (AES‑256‑GCM) and phnx (ChaCha20‑Poly1305) use standardized, well‑vetted algorithms and are considered stable. If you plan to use the experimental patterns in production, we strongly recommend performing your own security review and staying updated with new releases.

---

Installation

npm install jjspassende

jjspassende depends on Node.js's built‑in crypto module and the blakejs package (used for BLAKE2b keyed hashing to stay bit‑compatible with the Python implementation).

---

More Examples

Encrypting Binary Data (Buffer I/O via inputRaw / outputRaw)

const { JPassende } = require('jjspassende');
const fs = require('fs');

const jp = new JPassende();
const image = fs.readFileSync('photo.png');

const encPkg = jp.encode(image, 'nixl', 'secret', { inputRaw: true, outputRaw: true });

const decBytes = jp.decode(encPkg.encoded, 'nixl', 'secret', { inputRaw: true, outputRaw: true });

fs.writeFileSync('photo_decrypted.png', decBytes.decoded);

Choosing a Security Layer

const { JPassende, SecurityLayer } = require('jjspassende');

const jp = new JPassende();

const result = jp.encode('Sensitive data', 'phnx', 'strong', { layer: SecurityLayer.QUANTUM });
console.log(result.layer); // 'QUANTUM'

Using AAD (Additional Authenticated Data)

const { JPassende } = require('jjspassende');

const jp = new JPassende();
const aad = Buffer.from('user-id:12345');

const result = jp.encode('Hello', 'vail', 'secret', { aad });
const decoded = jp.decode(result.encoded, 'vail', 'secret', { aad });
console.log(decoded.decoded); // 'Hello'

Key Derivation

const { JPassende, SecurityLayer } = require('jjspassende');

const jp = new JPassende();

// HKDF as a first-class pattern (produces a self-describing package, like Python's jp.encode(..., 'hkdf', ...))
const derived = jp.encode('master-seed', 'hkdf', 'secret', { length: 32 });
console.log(derived.encoded.slice(0, 30) + '...');

const verified = jp.decode(derived.encoded, 'hkdf', 'secret');
console.log(verified.decoded.slice(0, 20) + '...');

// Lower-level, standalone helpers (no packaging/versioning, just raw KDF output)
const hkdfBytes = jp.deriveKeyHKDF('master-seed', 'salt', 'info', 32);
const pbkdf2Bytes = jp.deriveKeyPBKDF2('password', 'salt', 300000, 32);

List All Available Patterns

const { JPassende } = require('jjspassende');

const jp = new JPassende();
console.log(jp.listPatterns());
// ['vail', 'phnx', 'nixl', 'strx', 'rvrs', 'lfsr', 'aegs', 'cblk', 'cfbb', 'ofbb', 'hkdf', 'scrt', 'pbk2', 'blk3']

---

Error Handling

const { JPassende, InvalidPackageError } = require('jjspassende');

const jp = new JPassende();

try {
  jp.decode('not-valid-data', 'vail', 'secret');
} catch (err) {
  if (err instanceof InvalidPackageError) {
    console.error('Package error:', err.message);
  } else {
    console.error('Other error:', err.message);
  }
}

---

Issues and Contributions

Bug reports and feature requests are welcome via GitHub Issues. Pull requests should maintain the existing code style and include tests where appropriate.

---

Links

· GitHub repository: https://github.com/JCode-JCode/jjspassende

· npm page: https://www.npmjs.com/package/jjspassende

---

License

This project is licensed under the Apache License 2.0 – see the LICENSE file for details.

---

Designed and built with love by J Code