Message Encrypter: Secure Your Conversations in Seconds

Message Encrypter: Simple End-to-End Protection for Texts

What it does

• Encrypts text messages on the sender’s device and decrypts them only on the recipient’s device, preventing intermediaries from reading content.

Key features

• End-to-end encryption (E2EE): Messages are encrypted client-side using keys only available to users.
• Asymmetric cryptography: Uses public/private key pairs for secure key exchange and authentication.
• Session keys: Generates short-lived symmetric keys per session/message for performance.
• Forward secrecy: New ephemeral keys reduce risk if long-term keys are compromised.
• Integrity checks: Message authentication (MAC or digital signatures) prevents tampering.
• Easy UX: Automatic key management and one-click sharing for nontechnical users.

How it works (high-level)

1. Sender obtains recipient’s public key.
2. Sender generates a random session key, encrypts the message with a symmetric cipher (e.g., AES-GCM), then encrypts the session key with the recipient’s public key.
3. Encrypted session key + ciphertext + authentication tag are sent.
4. Recipient decrypts the session key with their private key, then decrypts the message and verifies integrity.

Security considerations

• Protect private keys locally (secure storage or hardware-backed keystore).
• Verify public keys to prevent man-in-the-middle attacks (QR scans, key fingerprints, or a trust-on-first-use policy).
• Keep software up to date to patch vulnerabilities.
• Use well-reviewed cryptographic libraries and avoid designing custom crypto.

When to use

• Private conversations, sensitive business communication, sharing personal data, or any situation where intermediaries shouldn’t read message content.

Limitations

• Does not hide metadata (who communicated, timing, message size) unless combined with anonymity tools.
• Endpoints can be compromised (screenshots, malware) which circumvents E2EE.
• Group messaging requires additional key management complexity.

Quick implementation checklist

• Choose proven algorithms (e.g., X25519 for key agreement, AES-GCM or ChaCha20-Poly1305 for symmetric encryption).
• Use authenticated key exchange (e.g., Noise protocols or Signal protocol) for forward secrecy and authentication.
• Store keys securely and implement key verification UX.
• Include message integrity and replay protection.
• Provide clear user guidance on trust verification and device backups.

Further reading (recommended topics)

• Signal Protocol, Noise Protocol Framework, public-key infrastructure (PKI), secure key storage, and threat modeling.