@incy/link-encoder

Encode VPN subscription URLs into incy://crypt1/<payload> deep links that the INCY iOS, Android, and Desktop clients decode automatically.

https://sub.your-provider.example/abc123token
                ⬇
incy://crypt1/AAECAwQFBgcICQoLNyIQL3rDwRZqnyoD8pGK…

Open the resulting link on a device with INCY installed → the subscription imports without the user copy-pasting anything.

Install

npm install @incy/link-encoder

Usage

import { encryptLink, decryptLink } from '@incy/link-encoder';

const link = encryptLink('https://sub.your-provider.example/abc123token', {
  name: 'My Provider VPN',
});

console.log(link);
// → incy://crypt1/AAECAwQFBgcICQoLNyIQL3rDwRZqnyoD8pGK…

// Decryption mainly for testing — the INCY apps do this end-side.
const decoded = decryptLink(link);
console.log(decoded.url, decoded.name);

encryptLink(url, opts?) accepts:

| Field | Type | Notes | |----------|-----------|----------------------------------------------------| | url | string | The http(s) subscription URL. Required. | | opts.name | string? | Display name shown in the receiver's import sheet. |

What this is

A small, dependency-free encoder for embedding subscription URLs in chat messages and websites without exposing the raw URL to scanners, moderation bots, or screenshots.

What this is NOT

This is not encryption-for-secrecy. The AES-256-GCM key is derived from constants and binary assets shipped inside this package — anyone reading the source can reconstruct it.

The exact same key already lives inside every INCY client (iOS, Android, Desktop). Anyone with a copy of those apps could already extract it using standard mobile reverse-engineering tools. Publishing this package reveals nothing new — it just makes the limitation explicit.

Threat model

| | Defended | |----------------------------------------------|:--------:| | Telegram chat moderation bots | ✅ | | Russian regulator (RKN) automated scanners | ✅ | | Casual screenshots and clipboard mishaps | ✅ | | grep over chat dumps | ✅ | | Determined reverse engineer with Frida | ❌ |

If the key is ever published publicly (e.g. extracted and shared on Twitter), a future INCY release will introduce crypt2/ with a fresh key. Existing crypt1/ links in chat histories will keep working forever — the clients never remove old schemes.

API

encryptLink(url: string, opts?: { name?: string }): string
decryptLink(link: string): { url: string; name?: string }

// For deterministic tests only — never reuse an IV with different
// plaintexts in production code.
encryptLinkDeterministic(url: string, opts: { iv: Buffer; name?: string }): string

// Runtime info
VERSION: string         // package version
SCHEME_VERSION: string  // current deep-link scheme, e.g. "crypt1"
KEY_FINGERPRINT: string // SHA-256 of K1 — for sanity checks

Cross-platform compatibility

A link generated by this package decodes bit-for-bit identically on iOS (CryptoKit), Android (javax.crypto), and Desktop (Compose Multiplatform JVM, also javax.crypto). A test vector pinned in the test suite guards against drift between updates.

License

MIT