Company
How TransferSize keeps files and accounts safer
TransferSize uses secure connections, checks every uploaded part and stores passwords safely. These controls help, but you still choose who gets the link, and you should keep your own copy of important files.
What each control covers
| Control | What it does | What it doesn’t do |
|---|---|---|
| HTTPS / WSS | Protects data while it travels. | Stop someone sharing a copy they downloaded. |
| Transfer password | Checks who can open a transfer. | Encrypt the files end to end. |
| Upload checks | Verify every part and every finished file. | Replace your own backup. |
| WebDAV app password | Keeps a file app separate from your account password. | Stay useful forever. Revoke it when an app no longer needs access. |
Transfer passwords
Each transfer password is protected with PBKDF2-SHA-256, a random salt and 600,000 rounds of processing, and only the result is stored. The password locks the transfer page. It doesn’t encrypt the files in your browser before upload, and it’s never included in TransferSize emails.
Upload checks
Large uploads are split into parts, and each part is checked with a checksum when it arrives. Before a link goes live, the size and checksum of every file are checked again. This lowers the chance of a broken upload, but it doesn’t replace your own backup.
Private chat
Chat uses HTTPS or WSS while messages travel. Messages are encrypted again, with AES-256-GCM, before they’re stored. This isn’t end-to-end encryption, because TransferSize must be able to read a message to deliver it or to review a copy that someone reports.
Account and app passwords
A public download page never gives anyone access to your account. WebDAV uses separate app passwords that you can revoke one at a time. Each is shown once and only a hash of it is stored.
What you should do
- Check who will receive the link.
- Send the password in a different message from the link.
- Use a short expiry, and remove links and app passwords you no longer need.
- Keep the original file.
- Report anything suspicious to support@transfersize.com.
Questions
Is TransferSize end-to-end encrypted?
No. Secure connections protect data while it travels, and chat messages are encrypted before storage. TransferSize can still read chat messages when needed to deliver them or review a safety report.
Can I take back a downloaded file?
You can close the link to stop future downloads. You can’t remove a copy someone already downloaded.
How do I report a security problem?
Email support@transfersize.com with the subject “Security report” and clear steps that show the problem. Don’t open or keep data that isn’t yours.
Updated September 26, 2026