Free RSA/AES Encryption/Decryption utility of Text and files for windows

EncryptEngine – RSA & AES Encryption Utility

A free, offline Windows tool for encrypting and decrypting text and files using industry-standard RSA and AES cryptography. Built for developers, IT professionals, and anyone who needs real encryption — not just encoding — without data ever leaving their machine.

Download EncryptEngine v1.0

Free on the Microsoft Store — no subscription, no ads.

Features

🔑 RSA Key Pair Generation

On startup, EncryptEngine automatically generates your RSA public/private key pair using the Windows CryptoAPI. Your public key is ready to share immediately for secure key exchange.

🔄 Secure Session Key Exchange

Generate a random AES-256 session key and encrypt it with another user's RSA public key. Share the encrypted session key safely over any channel — only the holder of the matching private key can unwrap it.

📝 Text Encryption

Encrypt any text using your own RSA key, a pasted RSA public key, an AES session key, or a password. Password-based encryption uses a random 16-byte salt stored alongside the ciphertext so decryption is always reliable.

🔓 Text Decryption

Decrypt ciphertext using your RSA private key, an AES session key, or a password. The app automatically extracts the embedded salt from password-encrypted messages and reconstructs the exact key used at encryption time.

📁 File Encryption

Encrypt any file using your RSA key, a pasted RSA public key, an AES-256 session key, or a password. Files are processed in streaming blocks — no full load into memory — with a real-time progress bar for large files.

📂 File Decryption

Decrypt any encrypted file. For password-encrypted files, the app reads the 16-byte salt header written during encryption and automatically reconstructs the correct key — no manual salt entry needed.

🔐 4 Key / Auth Modes

Every encrypt/decrypt operation supports four flexible key modes: your own RSA key, a pasted RSA public key, an AES session key, or a password — covering both asymmetric and symmetric workflows.

🔒 Fully Offline & Private

No internet connection required. All cryptographic operations run entirely on your machine using the native Windows CryptoAPI. Your keys, text, and files never leave your computer.

System Requirements: Windows 7 / 8 / 10 / 11 (32-bit or 64-bit)

Common Uses

📨 Secure Message Exchange

Share your RSA public key, receive an encrypted session key from the other party, and use it to decrypt messages — a practical end-to-end encrypted messaging workflow without needing a server.

🗄️ Protecting Sensitive Files

Encrypt confidential documents, backups, or archives with AES-256 or RSA before storing them on cloud drives, USB sticks, or shared servers.

🧑‍💻 Developer & Security Testing

Test RSA and AES encryption workflows, validate key exchange implementations, or prototype cryptographic protocols — all from a visual desktop interface without writing code.

🔑 Password-Based Encryption

Encrypt text or files with just a password — no key management required. Salted key derivation ensures the same password produces a unique key every time, protecting against rainbow table attacks.