In both work and personal life, we constantly share important files through messaging apps — contracts, financial statements, medical records, identity documents, and more. Many messaging platforms rely on transport encryption or cloud storage behavior for files. SafeW's encrypted file transfer is better suited for sensitive documents, but you should still verify app version, recipient device, and retention behavior. Haven't installed SafeW yet? Start with the Installation Guide.
How to Send Encrypted Files
SafeW file transfer is designed to feel like sending a normal attachment, but you should still check source, permissions, file size, and recipient status before sending sensitive content.
Sending Files in One-on-One Chats
Step-by-Step Instructions
- Open the chat conversation with your recipient
- Tap the attachment button (📎 icon) to the left of the message input field
- Choose the file source: Gallery, Camera, Documents, or File Manager
- Select the file(s) you want to send (multi-select is supported)
- Optionally add a text caption or description
- Tap the send button — the file is automatically encrypted and sent
During the upload, you'll see a progress bar. The file is first encrypted on your device, then uploaded to the server as ciphertext, and finally downloaded and decrypted by the recipient's device. Prompts and progress behavior may vary by platform and version. If sending fails, check network, permissions, and storage step by step.
Sending Files in Group Chats
Group file transfers are equally protected with end-to-end encryption. The process is identical to one-on-one chats — tap the attachment button in the group chat, select your files, and send. Group file delivery is handled together with group membership and encryption controls, reducing the risk of access by non-members.
Supported File Types and Sizes
| File Type | Supported Formats | Max Size |
|---|---|---|
| Documents | PDF, DOC, DOCX, XLS, XLSX, PPT, TXT and similar formats | Check current version |
| Images | JPG, PNG, GIF, WEBP, HEIC, BMP and similar formats | Check current version |
| Videos | MP4, MOV, AVI, MKV, WEBM and similar formats | Compress or split large files |
| Audio | MP3, WAV, AAC, OGG, FLAC and similar formats | Check current version |
| Archives | ZIP, RAR, 7Z, TAR.GZ and similar formats | Split large archives |
| Other | Depends on file picker and current app support | Check current version |
How File Encryption Works Under the Hood
Understanding how SafeW encrypts your files helps you appreciate why this approach is fundamentally more secure than traditional file sharing methods.
The Encryption Process Explained
- Local Encryption: The file may be encrypted locally using a high-strength symmetric encryption approach, depending on the current implementation and version notes
- Key Generation: Files should use independent keys or encryption contexts where supported by the current implementation
- Key Exchange: The file's encryption key is securely transmitted to the recipient through the already-established end-to-end encrypted channel
- Encrypted Upload: The encrypted file data is relayed through the service in encrypted form
- Encrypted Download: The recipient downloads the ciphertext from the server
- Local Decryption: The recipient's device uses the corresponding key to decrypt the file locally, restoring the original content
Comparison with Traditional File Transfer Methods
| Transfer Method | Encryption Type | Server Readable? | Interception Risk |
|---|---|---|---|
| Email Attachments | ⚠️ TLS | Yes | Medium-High |
| Cloud Storage Links | ⚠️ TLS | Yes | Medium-High |
| Standard Messengers | ⚠️ TLS | Yes | Medium |
| SafeW File Transfer | E2EE design | Usually not plaintext-readable | Relatively lower |
Advanced File Transfer Features
Disappearing Files
For particularly sensitive files, you can send them in a conversation with disappearing messages enabled. Whether files follow disappearing message rules depends on the current app prompt. Test with non-sensitive content first:
- Send files normally in a conversation where disappearing messages are already enabled
- Files auto-delete according to the conversation's disappearing message timer
- Once deleted, do not rely on chat history for recovery
- Ideal for sending temporary passwords, verification code screenshots, or sensitive contracts
File Forwarding Protection
SafeW lets you restrict the recipient's ability to forward files:
- If the current version provides “Prevent Forwarding,” use it to reduce further sharing risk
- Combined with screenshot protection, it can reduce the risk of further content spread
- Useful for temporary project files, internal notes, and content you do not want widely forwarded
Batch File Transfer
Need to send multiple files at once? SafeW supports batch selection and sending:
How to Send Multiple Files
- Tap the attachment button
- Long-press the first file in the file picker to enter multi-select mode
- Check all the files you want to send
- Tap send — all files are encrypted and uploaded sequentially
File Transfer Security Best Practices
Verify Identity Before Sending: Before sharing sensitive files, verify the recipient's identity using safety number verification to guard against man-in-the-middle attacks.
Use Disappearing Messages for Temporary Files: For passwords, verification codes, and other temporary information, use short-duration disappearing messages.
Compress Large Files First: Compressing large files before sending saves transfer time and reduces storage usage on both ends.
Regularly Clean Up Received Files: Periodically delete sensitive files from your device to minimize data exposure risk.
Prefer Trusted Networks: While SafeW's file transfer is end-to-end encrypted, using trusted networks (rather than public WiFi) adds an additional layer of metadata protection.
Important Notes
Storage Space: Received files occupy local device storage. Ensure your device has sufficient space before receiving large files.
Network Conditions: Large file transfers require a stable network connection. If a transfer is interrupted, follow the current app prompt to continue, retry, or resend.
File Retention Period: Retention for undownloaded files should be checked against the current app version. For important files, confirm that the recipient received them.
Want to learn more about SafeW's encryption technology? Read What Is End-to-End Encryption? Need to transfer files securely in groups? Check out the Group Encrypted Chat Guide. Also see our Privacy Tips and Online Privacy Protection Checklist.
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