Encrypt & Decrypt Utility Tool

Encrypt & Decrypt Text Utility Tool lets you protect any text behind a password using strong, standard encryption. Only someone with the correct password can read the message. Everything runs locally on your device. Nothing is transmitted, logged, or stored.

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HOW IT WORKS

Encrypt: enter the text you want to protect, enter a password, and the app creates an encrypted Base64 string. Copy it and paste it anywhere you want to send or store it: a message app, email, notes app, text file, or cloud drive. The recipient needs both the encrypted string and the password to read it.

Decrypt: paste the encrypted string, enter the password, and the original text is revealed. If the password is wrong or the encrypted string has been changed, decryption fails and the app tells you.

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NOT JUST FOR COMMUNICATION

This app is also useful for protecting your own notes, journal entries, drafts, and other private text. Encrypt the text, store the encrypted result wherever you want, and decrypt it when you need it.

One useful workflow: write sensitive material while offline, encrypt it before going online, and decrypt it again once offline. The plaintext does not need to sit on a connected device.

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WHO IT IS FOR

Originally developed for an investigative journalism firm where protecting sensitive sources and notes is not optional. Now free and open source for anyone who values privacy: investigative journalists, politicians, security professionals, police, military, activists, businesses handling confidential communication, or anyone who wants to exchange private text.

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WHAT THIS APP IS NOT

This is not a password manager, not a file encryption tool, and not a messaging app. It only encrypts and decrypts text on your device. It does not send anything anywhere.

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SECURITY

- AES-256-GCM authenticated encryption protects confidentiality and integrity. If the encrypted string is changed, decryption is refused.
- PBKDF2-SHA256 with 100,000 iterations slows brute-force and dictionary attacks.
- A random 16-byte salt is generated for every encryption, so the same text and password produce a different output every time.
- A random 12-byte IV is generated for every encryption.
- No internet permission is requested by the Android app.
- No passwords, plaintext, or ciphertext are saved by the app.
- No analytics, no crash reporting, and no third-party SDKs.
- Clipboard writes happen only after you press the copy button.
- The Clear button can clear visible fields and the clipboard after confirmation.

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IMPORTANT

If you forget your password, the message cannot be recovered. There is no account, no reset link, no backdoor, and no way for anyone, including the developer, to recover it. That is by design.

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GNU General Public License v3 (GPL v3) - free and open source.
Source: github.com/AmandaHernow/EncryptionDecryptionUtilityTool

Recent changes:
Updated the app to target the latest Android API level for continued Google Play compatibility.
Fixed the top system-bar area on newer Android devices so it matches the app design.
Fixed the Copy/Paste clipboard button so its text now updates correctly when changing language.
Minor compatibility and stability improvements.