@affectively/synthetic-watermark

Invisible watermarking for AI-generated content. Embeds synthetic origin markers into PNG images and MP3 audio files for authenticity verification and AI safety compliance.

Features

• Image Watermarking - Embeds invisible metadata into PNG files using iTXt chunks
• Audio Watermarking - Embeds metadata into MP3 files using ID3v2 tags
• Detection - Verify if content has synthetic origin markers
• Zero Dependencies - Uses only Node.js Buffer API
• Non-Destructive - Watermarks are stored in metadata, not visible/audible content
• AI Safety - Helps identify AI-generated content for authenticity verification

Installation

npm install @affectively/synthetic-watermark
# or
bun add @affectively/synthetic-watermark
# or
yarn add @affectively/synthetic-watermark

Quick Start

Image Watermarking

import {
  embedImageWatermark,
  detectSyntheticImageWatermark,
} from '@affectively/synthetic-watermark';

// Watermark an AI-generated image
const pngBuffer = await fs.readFile('ai-generated-image.png');
const watermarkedImage = embedImageWatermark(pngBuffer, 'png', {
  source: 'dalle',
  model: 'dall-e-3',
  platform: 'MyApp',
});

// Save the watermarked image
await fs.writeFile('watermarked-image.png', watermarkedImage);

// Detect watermark
const detected = detectSyntheticImageWatermark(watermarkedImage);
if (detected) {
  console.log('Synthetic origin detected:', detected);
  // { platform: 'MyApp', source: 'dalle', model: 'dall-e-3', timestamp: 1234567890 }
}

Audio Watermarking

import {
  embedAudioWatermark,
  detectSyntheticWatermark,
} from '@affectively/synthetic-watermark';

// Watermark AI-generated audio
const mp3Buffer = await fs.readFile('tts-audio.mp3');
const watermarkedAudio = embedAudioWatermark(mp3Buffer, 'mp3', {
  source: 'tts',
  platform: 'MyApp',
});

// Save the watermarked audio
await fs.writeFile('watermarked-audio.mp3', watermarkedAudio);

// Detect watermark
const detected = detectSyntheticWatermark(watermarkedAudio);
if (detected) {
  console.log('Synthetic audio detected:', detected);
  // { platform: 'MyApp', source: 'tts', timestamp: 1234567890 }
}

Convenience Functions

For Images

import {
  watermarkDallEImage,
  watermarkGeminiImage,
  watermarkDigitalTwinImage,
  watermarkCyranoImage,
} from '@affectively/synthetic-watermark';

// Pre-configured for specific AI image generators
const watermarked = watermarkDallEImage(imageBuffer, 'png', optionalUserIdHash);

For Audio

import {
  watermarkDigitalTwinAudio,
  watermarkHologramAudio,
  watermarkCyranoAudio,
} from '@affectively/synthetic-watermark';

// Pre-configured for specific TTS systems
const watermarked = watermarkCyranoAudio(audioBuffer, 'mp3');

Watermark Format

Image Watermark (PNG iTXt chunk)

SyntheticOrigin: SYNTHETIC_IMAGE|platform|source|timestamp|userIdHash|model

Audio Watermark (ID3v2 COMM frame)

SYNTHETIC_ORIGIN: SYNTHETIC_AUDIO|platform|source|timestamp|userIdHash

API Reference

Image Functions

embedImageWatermark(buffer, format, config?)

Embeds an invisible watermark into a PNG image.

• buffer - Image data (Uint8Array)
• format - Image format (currently only 'png' supported)
• config - Optional configuration:
  • platform - Platform identifier (default: 'SYNTHETIC')
  • source - Source system (e.g., 'dalle', 'gemini')
  • model - Model name (e.g., 'dall-e-3')
  • userIdHash - Hashed user ID for audit trail

Returns: Watermarked image buffer

detectSyntheticImageWatermark(buffer)

Detects and extracts watermark from PNG image.

Returns: ImageWatermarkConfig | null

Audio Functions

embedAudioWatermark(buffer, format, config?)

Embeds an invisible watermark into MP3 audio.

• buffer - Audio data (Buffer)
• format - Audio format (currently only 'mp3' supported)
• config - Optional configuration:
  • platform - Platform identifier (default: 'SYNTHETIC')
  • source - Source system (e.g., 'tts', 'hologram')
  • userIdHash - Hashed user ID for audit trail

Returns: Watermarked audio buffer

detectSyntheticWatermark(buffer)

Detects and extracts watermark from MP3 audio.

Returns: WatermarkConfig | null

Use Cases

1. AI Safety Compliance - Mark AI-generated content for authenticity verification
2. Content Authentication - Verify the origin of synthetic media
3. Audit Trail - Track when and by whom content was generated
4. Platform Trust - Help users identify AI-generated content
5. Regulatory Compliance - Support emerging AI content disclosure requirements

Technical Details

PNG Watermarking

• Uses iTXt (International Text) chunk per PNG specification
• Inserted before IEND chunk
• Includes proper CRC32 checksum
• Non-destructive to image data

MP3 Watermarking

• Uses ID3v2.3 COMM (Comment) frame
• Replaces existing ID3 tag if present
• Syncsafe integer encoding for size
• Compatible with standard ID3 readers

Browser Support

Works in Node.js and browser environments (requires Buffer polyfill in browser).

License

MIT © AFFECTIVELY