Cipher — Privacy Notes

Notes. Encrypted. Local. Nothing more.

Quick Start

Installation

Option 1: IzzyOnDroid (recommended for privacy-focused users)

F-Droid → Settings → Repositories → Add custom repo
https://apt.izzysoft.de
→ Search "Cipher"

Option 2: GitHub Releases

Download APK → adb install CipherNotes-release.apk
Or: sideload via file manager

Option 3: Build from source

git clone https://github.com/Cris1099/cipher-notes
cd cipher-notes
./gradlew assembleRelease
# APK: app/build/outputs/apk/release/CipherNotes-release.apk

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Why Cipher?

• Your phone is your vault. Everything stays on device.
• No accounts. No login. No tracking who you are.
• Small footprint. No bloat.
• Auditable. Open source. Every line of code visible.
• Privacy by design. No internet permission. Zero telemetry hooks.

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Open Source Libraries

All dependencies are FOSS and auditable:

• Jetpack Compose (Apache 2.0) — UI framework
• Room (Apache 2.0) — SQLite wrapper
• Hilt (Apache 2.0) — Dependency injection
• kotlinx-serialization (Apache 2.0) — JSON codec
• Timber (Apache 2.0) — Logging
• Android Security Crypto (Apache 2.0) — Android-level crypto

What it does NOT do

• Cloud sync
• Account creation
• Analytics
• Advertisements
• Internet calls (network config enforces it)
• Crash reporting
• Any telemetry

Privacy by design

• No INTERNET permission in AndroidManifest
• Network security config blocks all outbound traffic at OS level
• Passwords never stored — derived on-demand via PBKDF2
• Encryption uses: PBKDF2 (200k iterations) + AES-256-GCM
• All data stays on device — Room SQLite database

Building

# Clone
git clone https://github.com/Cris1099/cipher-notes
cd cipher-notes

# Build
./gradlew assembleRelease

# Output: app/build/outputs/apk/release/CipherNotes-release.apk

Installation

From GitHub Releases (when available)

Download APK → sideload via adb install app-release.apk

From F-Droid

Coming soon.

FAQ

Q: How is the app so small?

• Minimal dependencies (no Gson, Retrofit, Firebase)
• Kotlin/Compose is efficient
• No embedded runtimes (not Flutter, not React Native)

Q: What if I lose my password?

• You can't decrypt the note. That's the point.
• Consider using a password manager.

Q: Can you read my notes?

• No. The code is open-source. You can audit it.
• No cloud, no accounts, no servers.

Q: Will you add cloud sync?

• No. Not without changing the privacy model fundamentally.
• Recommend: sync files via Syncthing / Nextcloud locally.

Q: Is this production-ready?

• Not yet. Still v1.1.1
• Use for personal notes.
• Audit the crypto code if deploying at scale.

License

MIT. Use, modify, distribute freely.

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Cipher v1.1.1 — because your notes are yours.

Built with Kotlin + Jetpack Compose. No telemetry. No cloud. No BS.