HiddenMark

Invisible digital watermarking for images and audio. Embed and detect watermarks using frequency-domain techniques — entirely in the browser or via CLI and multi-language SDKs.

How It Works

Image watermarking uses ring-based frequency modulation in FFT space. A deterministic pattern is generated from a secret key and embedded into the high-frequency rings of the image's Fourier transform, making the watermark invisible to the human eye but detectable with the correct key.

Audio watermarking uses spread-spectrum correlation with bandpass filtering (2–8 kHz). A pseudo-random noise sequence derived from the key is embedded into audio chunks, preserving audio quality while enabling reliable detection.

Features

• Browser-based — all processing happens client-side, no files are uploaded
• Image & Audio — supports both image (PNG) and audio (WAV) watermarking
• Multi-language SDKs — Go, Python, Rust, C++, Dart, Java, Kotlin, Swift
• Cross-language compatible — watermarks embedded in one language can be detected in any other
• CLI tools — embed and detect watermarks from the command line

Quick Start

Web App

npm install
npm run dev

Open the app in your browser to embed or detect watermarks interactively.

CLI

# Embed a watermark into an image
npx tsx cli/embed.ts <input-image> <key-file> [output-image]

# Detect a watermark in an image
npx tsx cli/detect.ts <input-image> <key-file>

# Embed a watermark into audio
npx tsx cli/audio-embed.ts <input-audio> <key-file>

# Detect a watermark in audio
npx tsx cli/audio-detect.ts <input-audio> <key-file>

SDKs

Each SDK provides the same core watermarking functionality:

Language	Path
Go	sdks/go/
Python	sdks/python/
Rust	sdks/rust/
C++	sdks/cpp/
Dart	sdks/dart/
Java	sdks/java/
Kotlin	sdks/kotlin/
Swift	sdks/swift/

Development

npm run dev            # Start dev server
npm run build          # Production build
npm run check          # TypeScript & Svelte validation
npm test               # Run tests
npm run benchmark      # Performance benchmarks

Database Migrations

npm run migrate          # Apply migrations locally
npm run migrate:remote   # Apply migrations to production

Tech Stack

• Frontend: SvelteKit, Svelte 5, Tailwind CSS, TypeScript
• Deployment: Cloudflare Pages + Workers + D1
• Core Algorithm: Cooley-Tukey FFT (pure TypeScript, no native dependencies in browser)