Opey CryptSecure

VERSION 2.6.0 LATEST RELEASE QUANTUM-SAFE

CryptSecure

Quantum-Safe Encryption for Messages, Files & Entire Folders

The first easy-to-use Windows encryption tool combining traditional cryptography with NIST-standardized post-quantum algorithms. Now with drag-and-drop file & folder bundling — wrap your message and an entire directory into a single secure envelope. 100% offline. No cloud. No tracking.

Post-Quantum Drag & Drop Folder Auto-Zip All-in-One Envelope
Download v2.6.0 Free from Microsoft Store See How It Works User Guide
Need the previous release? Download v2.4.3 →

“Encryption that’s ready for the quantum era — without the complexity. Local, offline, user-controlled.”

Post-Quantum Encryption
Zero Cloud Dependencies
Works 100% Offline
NIST-Standardized
Free Forever
New in v2.6.0

Drag, Drop, Encrypt. Done.

v2.6.0 makes encrypting an entire project as easy as dragging it onto the window. Files, folders, and your message all get bundled into a single secure envelope.

One Envelope. Everything Inside.

Drop a file. Drop a folder. Drop a dozen of each. CryptSecure automatically zips directories with their structure intact, attaches your message, and produces a single encrypted envelope ready to send through any channel.

  • Drag-and-drop files and entire folders
  • Directories auto-zip with full structure preserved
  • Message text + all attachments → one secure bundle
  • Recipient gets back the original files exactly as sent
  • Works with any file type and any folder size

Drop files or folders here

or click to browse

report.pdf contract.docx /case-files/ /photos/
↓
secure-envelope.csenv
LIVE DEMO

Experience the v2.6.0 Workflow In Your Browser

Test the seamless drag-and-drop mechanics and secure cryptographic processing firsthand right now.

Launch the Interactive Demo
The Quantum Threat

Why Quantum-Safe Encryption Matters

Quantum computers powerful enough to break today’s encryption are coming. Adversaries are already collecting encrypted data — waiting for the day they can decrypt it. CryptSecure protects you now.

Auto

Picks the strongest mode for your key. Recommended default.

Standard

Classical RSA + AES-256-GCM. Fast and widely compatible.

Quantum-Safe

ML-KEM-1024 post-quantum. NIST FIPS 203 standard.

Maximum

Classical + Quantum combined. Best protection available.

Capabilities

What CryptSecure Does

Fast, reliable encryption combining proven classical algorithms with NIST-standardized post-quantum protection. No command line, no cloud, no complexity.

Drag & Drop Everything

Drag any combination of files and folders onto the window. No file picker dialogs, no clicking through directories — just drop and go.

Folder Auto-Zip

Drop an entire directory and CryptSecure zips it automatically — preserving the full folder structure inside the encrypted envelope.

All-in-One Secure Envelope

Your message text, files, and folders are wrapped into a single encrypted envelope. One file to send — recipient unpacks everything back to original form.

Post-Quantum Encryption

ML-KEM-1024 (NIST FIPS 203) protects against future quantum computer attacks. The first standardized quantum-resistant algorithm for civilian use.

Hybrid Mode

Combines classical RSA with post-quantum ML-KEM through HKDF. An attacker must break BOTH algorithms to decrypt your data.

Plain-English Modes

No cryptographer jargon. Choose Standard, Quantum-Safe, or Maximum from a simple dropdown — or let Auto pick the best mode for your key.

AES-256-GCM

Upgraded from AES-128 to AES-256-GCM authenticated encryption. Industry standard for high-security symmetric encryption.

Argon2id Passphrase

OWASP-recommended Argon2id passphrase protection adds a second layer of security. Resistant to brute-force and GPU attacks.

Hybrid Key Management

Generate, import, export, and manage RSA-only, ML-KEM-only, or Hybrid keys. Old v2.4 keys still work — no migration needed.

100% Offline

No internet connection required. No servers, no accounts, no telemetry. Zero external communication — ever.

Backward Compatible

Every file encrypted with CryptSecure v2.4.3 and earlier still decrypts automatically in v2.6.0. No migration, no risk of being locked out.

Professional-Grade Security

NIST-Standardized Cryptography

CryptSecure implements only published, vetted algorithms from official standards.

ML-KEM-1024 FIPS 203 Post-Quantum
AES-256-GCM SP 800-38D Authenticated
RSA-4096 OAEP-SHA256 Padding
Argon2id RFC 9106 / OWASP

v2.6.0 Bundle Flow: From Drop to Envelope

Files + Folders Dropped
→
Folders Auto-Zipped (Structure Preserved)
+
Your Message Text
→
Single Secure Envelope

Everything bundled in one encrypted file — easy to send, easy to receive.

Standard Encryption Flow (Classical)

Your Bundle (Message + Files + Zipped Folders)
→
AES-256-GCM Encrypts Content
→
RSA-OAEP Encrypts AES Key
→
Secure Envelope

Maximum Mode: Hybrid Classical + Post-Quantum

Your Bundle (Message + Files + Zipped Folders)
→
RSA Wrap (Classical Secret)
+
ML-KEM Wrap (Quantum Secret)
→
HKDF Combines Both
→
AES-256-GCM Encrypted

An attacker must defeat BOTH classical and quantum encryption to read your data.

Getting Started

How to Use CryptSecure

Simple, intuitive workflow with drag-and-drop bundling and quantum-safe protection built in.

1

Create or Import Keys

Use the built-in Key Manager to create RSA-only, ML-KEM-only, or Hybrid keypairs (combining both). Existing v2.4 RSA keys continue to work without changes.

2

Exchange Public Keys

Share your public key with anyone you want to communicate with. Public keys can be sent over any channel — even insecure ones.

3

Choose Your Security Level

Select an encryption mode: Standard (fast), Quantum-Safe (future-proof), or Maximum (both combined). Or leave it on Auto and let CryptSecure pick the best mode for your key.

4

Drop Your Files & Folders NEW IN 2.6.0

Drag files and entire folders directly onto the CryptSecure window. Folders are automatically zipped with their full directory structure preserved. Type your message in the same window — everything becomes one bundle.

5

Encrypt to a Secure Envelope

Add an optional Argon2id passphrase and click Encrypt. CryptSecure produces a single secure envelope containing your message, files, and folders — ready to send.

6

Send & Decrypt

Send the encrypted envelope via email, chat, or any method. Only the recipient’s private key can decrypt it, and they’ll get back the original message, files, and folder structures exactly as you sent them.

i Need More Detail?

Our complete step-by-step guide covers setup, hybrid key creation, drag-and-drop bundling, mode selection, and best practices.

Read the Full User Guide →
Use Cases

Who Uses CryptSecure

Trusted by professionals who need true offline encryption — now with future-proof quantum protection and full-folder bundling.

LAW

Attorneys & Legal Teams

Send entire case folders in one encrypted envelope. Privileged communications and full discovery sets stay client-controlled — and quantum-safe for decades.

INV

Investigators & Journalists

Bundle evidence folders, source notes, and photos into one secure envelope. Chain-of-custody intact, sources protected, future-proof encrypted.

BIZ

Corporate Teams

Share entire project folders — contracts, financials, and strategy docs — with one drag-and-drop. Protected against “harvest now, decrypt later” attacks.

IT

IT & Security Professionals

Test post-quantum workflows, package config bundles or log directories securely, prepare your organization for the quantum era.

MED

Healthcare & Finance

HIPAA-friendly encryption for patient record folders and financial document sets. Drag the whole folder — one envelope, fully protected.

YOU

Privacy-Conscious Users

Anyone tired of “free apps” that spy on you. True privacy, future-proof, drag-and-drop simple — without surveillance capitalism.

Why Choose CryptSecure

How CryptSecure Compares

A privacy app is only as strong as its architecture.

Feature CryptSecure 2.6.0 Other Encryption Tools Signal/WhatsApp
Post-Quantum Encryption ✓ ✗ ✗
Hybrid Classical + Quantum ✓ ✗ ✗
Drag-and-Drop Files & Folders ✓ Varies Limited
Auto-Zip Directories ✓ ✗ ✗
Message + Files in One Envelope ✓ Varies ✗
Works 100% Offline ✓ ✓ ✗
No Account Required ✓ ✓ ✗
No Server Dependencies ✓ ✓ ✗
User-Owned Key Storage ✓ ✓ ✗
Plain-English Mode Selection ✓ ✗ N/A
Encrypt Any File Type ✓ ✓ Limited
Backward Compatible ✓ Varies N/A
Zero Telemetry/Tracking ✓ Varies ✗
Previous Release

Looking for CryptSecure v2.4.3?

The previous stable release is still available on the Microsoft Store for users who need it.

CryptSecure v2.4.3

The prior stable release. Still fully functional, still free, still 100% offline. Note that drag-and-drop, folder auto-zip, and the unified envelope workflow are v2.6.0 features — and files encrypted with v2.4.3 decrypt automatically in v2.6.0, so most users should upgrade.

Get v2.4.3 →
Questions

Frequently Asked Questions

What’s new in v2.6.0? +
v2.6.0 keeps all the post-quantum and hybrid encryption from v2.4.3 and adds three big workflow upgrades: full drag-and-drop support for files and folders directly onto the window, automatic folder zipping (drop a directory and CryptSecure compresses it with the full structure preserved), and the all-in-one secure envelope — your message text, attached files, and zipped folders all get wrapped into a single encrypted file that’s easy to send and easy for the recipient to unpack.
Can I really drag an entire folder onto CryptSecure? +
Yes. Drop any folder — or several folders — onto the CryptSecure window and it automatically zips each one, preserving the full subdirectory structure. You can mix folders and individual files in the same drop. When the recipient decrypts, they get the original folder structures back exactly as you sent them.
What goes into the “secure envelope”? +
Everything you’ve added in CryptSecure becomes part of one encrypted envelope: your message text, any individual files you dropped, and any folders (which are auto-zipped first). The result is a single file you send to the recipient. They decrypt once and recover the original message, files, and folder structures — no separate downloads, no juggling multiple attachments.
Should I download v2.6.0 or v2.4.3? +
Most users should download v2.6.0 — it’s the latest stable release and includes drag-and-drop, folder auto-zip, and the unified envelope workflow on top of everything v2.4.3 already had. We keep v2.4.3 available on the Microsoft Store for users with specific compatibility needs or those who want to stick with the prior version. Both versions read each other’s encrypted files, so you won’t lose access to your data.
What is post-quantum encryption and why do I need it? +
Today’s RSA encryption relies on math problems that classical computers can’t solve quickly. But large quantum computers — using algorithms like Shor’s algorithm — could break RSA in hours instead of millennia. Quantum computers powerful enough to do this don’t exist yet, but adversaries are already capturing encrypted data today, planning to decrypt it later when quantum technology matures (“harvest now, decrypt later”). Post-quantum algorithms like ML-KEM are designed to resist both classical AND quantum attacks, protecting your data for decades to come.
Will my old encrypted files from v2.4.3 still work in v2.6.0? +
Yes. CryptSecure v2.6.0 is fully backward compatible. Every file and message encrypted with v2.4.3 (or any earlier version) decrypts automatically. The program detects the format and uses the right method. Your existing RSA keys also continue to work — there’s no migration needed. You only need to create a Hybrid key when you want to use the new quantum-safe modes.
Which encryption mode should I use? +
For most users: leave it on Auto. It picks the strongest mode your selected key supports. For day-to-day use with existing RSA keys, you’ll get Standard mode (RSA + AES-256). If you create a Hybrid key, Auto uses Maximum mode — classical and post-quantum combined. You can also pick a mode manually if you want to force a specific level. Each option includes a built-in tooltip explaining what it does.
Is there a size limit for folders or attachments? +
There’s no hard-coded size limit imposed by CryptSecure — practical limits come down to your available disk space and the maximum file size your chosen transport (email, chat app, etc.) supports. For very large bundles, plan to send the encrypted envelope via a file-sharing method that supports large files.
Is CryptSecure really free? +
Yes, CryptSecure is completely free to download and use from the Microsoft Store. No subscriptions, no premium tiers, no hidden costs, no ads.
Does it require an internet connection? +
No. CryptSecure works 100% offline. It never connects to the internet, never sends data anywhere, and never communicates externally. All encryption — including the new post-quantum operations, zipping, and bundling — happens entirely on your device.
How do I share encrypted messages? +
First, exchange public keys with your recipient (this can be done over any channel — even insecure ones). Then encrypt your message and any files/folders using their public key, and send the resulting envelope via email, chat, file transfer, or any method you prefer. Only their private key can decrypt it.
What file types can I encrypt? +
Any file type — PDFs, Word documents, images, ZIP archives, executables, videos, spreadsheets, databases — anything. And in v2.6.0, you can drop entire folders too. CryptSecure encrypts the message + all attached files/folders as a single secure bundle.
What standards does CryptSecure follow? +
CryptSecure implements algorithms from published, vetted standards: NIST FIPS 203 (ML-KEM post-quantum), NIST SP 800-38D (AES-256-GCM authenticated encryption), RFC 9106 (Argon2id passphrase derivation), RFC 5869 (HKDF for hybrid key combining), and the standard RSA-OAEP with SHA-256 padding. All algorithms are well-studied and recommended by cryptographic experts.
What if I lose my private key? +
If you lose your private key, messages encrypted with your public key cannot be decrypted — by anyone, including you. This is by design. We recommend backing up your private keys securely (e.g., encrypted USB drive stored safely).
How does Hybrid mode actually work? +
Hybrid (Maximum) mode generates two separate secrets — one wrapped with classical RSA, one wrapped with post-quantum ML-KEM. Both secrets are combined through HKDF-SHA256 to derive the AES-256 encryption key. To decrypt, an attacker must defeat BOTH the RSA and the ML-KEM cryptography. Even if one algorithm has an unknown weakness, your data stays protected by the other. This is the same approach used by major web browsers and TLS for hybrid post-quantum transport.

Download CryptSecure Free

Drag, drop, encrypt. Quantum-safe. Your data, your keys, your control.

Get CryptSecure v2.6.0 from Microsoft Store

Windows 10/11 • No installation required • No account needed • 100% Offline

Or download the previous version (v2.4.3) →

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