📖 How to Use CifraGuard

Complete step-by-step guide for secure file sharing

🛡️ Privacy-First File Sharing

Your file is encrypted in your browser before upload. Our servers never see your original file contents. Encrypted files exist on the server only briefly for email delivery, then are deleted.

Protects against:

  • accidental sharing / forwarding of the file alone
  • server-side breaches of stored uploads
  • passive interception of one email only

Does not protect against:

  • compromised recipient device/browser
  • compromise of both email inboxes
  • phishing/social engineering of the recipients

⚡ Quick Start (3 Steps)

1️⃣
Upload & Encrypt

Select your file and enter two email addresses

2️⃣
Separate Delivery

Encrypted file and key sent to different emails

3️⃣
Decrypt & Download

Recipient combines both to get original file

📋 Detailed Instructions

1

📤 Sending a Secure File

1.1 Navigate to Send File

Click the "📤 Send File" button on the home page or use the navigation menu.

1.2 Select Your File

Choose a file up to 1MB. Most common document/image/archive formats are supported. Executables/scripts are blocked for safety. If your file type is blocked, zip it first and upload the .zip.:

⚠️ File Size Limit: Maximum 1MB per file for free tier.
1.3 Enter Email Addresses

Recipient Email: Where the encrypted file will be sent

Key Email: Where the decryption key will be sent

💡 Security Tip 1: Using two different inboxes reduces risk. Anyone who has only the encrypted file or only the key can’t decrypt. If both inboxes (or the device) are compromised, the file can be decrypted — so treat the key like a password.
💡 Security Tip 2: Send the encrypted file to the recipient and send the key to yourself (or a second channel). Then deliver the key via a trusted method (phone call, Signal, in-person, etc.).
1.4 Automatic Encryption

When you select a file, CifraGuard automatically:

  • 🔐 Encrypts the file using AES-256-GCM (authenticated encryption). A fresh random nonce/IV is generated for each file.
  • 🔑 Generates a unique decryption key
  • ✅ Confirms encryption was successful
1.5 Send the File

Click "🚀 Send Secure File" to upload and send via email.

🔒 What Happens During Upload:
  • Only the encrypted file is uploaded.
  • The encrypted file is stored temporarily to send emails.
  • After successful delivery, the encrypted file is deleted.
  • We do not store your original file contents.
  • If email delivery fails, the encrypted file may be retained briefly for retry/debugging (then cleaned up).
2

📧 Receiving Secure Files

2.1 Check Your Email

You'll receive two separate emails:

📎 Email #1: Encrypted File

Contains the encrypted file as an attachment with instructions.

🔑 Email #2: Decryption Key

Contains the decryption key needed to unlock the file.

💡 Pro Tip: If emails go to different addresses, make sure both recipients coordinate to decrypt the file.
2.2 Download the Encrypted File

From the first email, download the attached .encrypted file to your computer.

2.3 Copy the Decryption Key

From the second email, copy the long decryption key (it looks like random characters).

3

🔓 Decrypting Your File

3.1 Go to Decrypt Page

Visit cifraguard.com/decrypt or click "🔓 Decrypt File" in the navigation.

3.2 Upload Encrypted File

Click "Choose File" and select the .encrypted file you downloaded from the email.

3.3 Enter Decryption Key

Paste the decryption key from the second email into the text area.

⚠️ Important: Make sure to copy the entire key, including any special characters. Extra spaces at the beginning or end can cause decryption to fail.
3.4 Decrypt & Download

Click "🔓 Decrypt & Download". The original file will be decrypted and automatically downloaded to your computer.

🔒 Security During Decryption:
  • Decryption happens entirely in your browser.
  • No data is sent to our servers during decryption.
  • Original file is reconstructed on your device only.
  • Decryption happens entirely in your browser. The key you paste is used locally for decryption and is not uploaded to our servers.
  • If decryption fails, double-check you copied the full key and didn’t include whitespace.

🛡️ Security Features

🔐 Encryption
  • AES-256-GCM encryption
  • Client-side encryption only
  • Unique key per file
  • Browser-based cryptography
🚫 Privacy Protection
  • No tracking cookies
  • No personal data storage
  • Automatic file deletion
  • Client-side encryption + no persistent storage of files/keys

⏱️ Usage Limits

📤 File Uploads
  • Rate: 1 file per hour per IP
  • Size: Maximum 1MB per file
  • Types: Most common document/image/archive formats are supported. Executables/scripts are blocked for safety. If your file type is blocked, zip it first and upload the .zip.
📞 Contact Form
  • Rate: 1 message per hour
  • Protection: Spam filtering active
  • Response: Usually within 24 hours

🔧 Troubleshooting

❌ Common Issues & Solutions

  • Check file size (must be under 1MB)
  • Verify internet connection
  • Try refreshing the page
  • Check if you've exceeded rate limit (1 file per minute)

  • Ensure you copied the complete decryption key
  • Remove any extra spaces before/after the key
  • Verify you uploaded the correct .encrypted file
  • Try using a different browser

  • Check spam/junk folders
  • Verify email addresses were entered correctly
  • Wait a few minutes for delivery
  • Contact us if emails consistently don't arrive

Ready to Start?

📤 Send Your First File 🔓 Decrypt a File 📞 Get Help

This guide covers all features of CifraGuard. For additional help, please contact us.