# Metadata Privacy & MAT2 Technical Reference

Subsystem: Snigdha Privacy Suite
Tools: MAT2 (CLI) & Metadata Cleaner (GUI)
Distribution: Snigdha OS Decentralized

# 1. What is Metadata?

Files and digital media contain invisible hidden metadata added automatically by cameras, smartphones, office suites, and operating systems:

• EXIF Data: GPS latitude/longitude coordinates, camera model, lens serial number, precise timestamp.
• Office Document Metadata: Author name, company, revision history, internal network paths, printer names.
• Audio/Video Tags: Software encoders, artist tags, recording hardware fingerprints.
• PDF Metadata: Creator software, operating system version, embedded font licensing IDs.

# 2. Core Operation: Non-Destructive Cleaning

MAT2 enforces a strict non-destructive invariant:

• Never Overwrites in Place: The source file is parsed in read-only mode.
• Cleaned Copy Creation: Cleaned files are emitted with .cleaned in the name: input.png -> input.cleaned.png
• Preserves Original Evidence: The original document remains bit-for-bit unchanged.

# 3. Supported File Formats (Installed MAT2 Version)

# 4. Technical Limitations & Pitfalls

• Steganography & Watermarks: MAT2 cannot detect or remove invisible watermarks or data hidden within pixel values.
• Semantic Metadata: If an author's name or address is written inside the visible body text of a document, MAT2 will not alter it.
• Recompression Artifacts: Stripping metadata from lossy formats (such as JPEG) may involve image re-encoding, slightly altering file size.