# Standard Encoding

Standard encoding is the primary method for hiding data within images using QuantHide's post-quantum cryptography.

## How It Works

```
┌─────────────┐    ┌──────────────┐    ┌─────────────┐
│  Your Data  │ -> │  Encryption  │ -> │ Steganography│ -> Encoded Image
│ (text/file) │    │  (Kyber1024) │    │    (LSB)     │
└─────────────┘    └──────────────┘    └─────────────┘
```

### Step-by-Step Process

1. **Data Preparation**
   - Text messages are UTF-8 encoded
   - Files are read as binary data
   - Metadata (filename, size) is preserved for files

2. **Encryption**
   - Password → Argon2id → Key derivation
   - Kyber1024 encapsulation generates session key
   - ChaCha20-Poly1305 encrypts the data
   - Random padding added for security

3. **Embedding**
   - Encrypted data converted to bits
   - LSB (Least Significant Bit) encoding into image pixels
   - EXIF metadata stripped from output

## Usage

### Encoding a Message

1. **Load Cover Image**
   - Drag & drop or click to select
   - Supported: PNG, JPEG, BMP, WebP
   - Larger images = more capacity

2. **Enter Your Message**
   - Type in the message panel
   - Or switch to "File" tab to embed a file

3. **Set Password**
   - Strong password recommended
   - Same password needed for decoding

4. **Click Encode**
   - Wait for processing
   - Save the resulting PNG image

### Encoding a File

1. Load cover image (same as above)
2. Click **File** tab in message panel
3. Click **Select File** or drag & drop
4. Set password
5. Click **Encode**

## Best Practices

### Choosing a Cover Image

| Image Type | Recommendation |
|------------|----------------|
| **Photos** | ✅ Excellent - natural noise hides data well |
| **Screenshots** | ⚠️ Okay - less natural variation |
| **Solid colors** | ❌ Poor - changes more visible |
| **Small images** | ❌ Limited capacity |

### Password Guidelines

- **Minimum**: 12 characters
- **Recommended**: 16+ characters
- **Include**: uppercase, lowercase, numbers, symbols
- **Avoid**: dictionary words, personal info

## Output Format

- **Always PNG** - lossless compression preserves hidden data
- **Original dimensions** - image size unchanged
- **No EXIF data** - metadata stripped for privacy
- **Slightly larger file** - due to PNG encoding

## Capacity

The amount of data you can hide depends on:

```
Capacity = (Width × Height × 3 channels × bits_per_channel) / 8 bytes
```

Example for a 1920×1080 image with 2 bits per channel:
```
1920 × 1080 × 3 × 2 / 8 = 1,555,200 bytes ≈ 1.48 MB
```

> **Note**: Actual usable capacity is lower due to encryption overhead (~500 bytes for headers and authentication).

## Troubleshooting

### "Image too small for data"
- Use a larger cover image
- Reduce message/file size
- Try Split Encoding for large files

### "Encoding failed"
- Check image format is supported
- Ensure image isn't corrupted
- Try a different cover image

### Quality concerns
- Use high-resolution photos
- Avoid already-compressed images
- PNG sources work best

## See Also

- [Encryption Details](Encryption-Details.md)
- [Capacity Calculator](Capacity-Calculator.md)
- [Split Encoding](Split-Encoding.md)
- [Best Practices](Best-Practices.md)