1
Install the Extension or Add-in
Add LockDoc to your email client. For Gmail, install our Chrome extension. For Outlook, add our Office Add-in. It takes less than a minute to connect your LockDoc plan.
Sending Encrypted Files via Email
LockDoc integrates directly into Gmail and Outlook, making secure file sharing as easy as sending a regular attachment. Here's how it works:
2
Select Your Files
When composing an email, click the LockDoc upload button. Select any number of files—there's no file size or file count limit. Files can be documents, images, videos, or any other format.
3
Automatic On-Device Encryption
Your files are encrypted right on your device using military-grade AES-256-GCM encryption before being uploaded. A unique passphrase is generated for each upload, ensuring maximum security.
4
Choose Your Delivery Method
Select how your recipient will receive the decryption passphrase: AutoLink embeds it securely in the download link, or Manual Copy lets you share it separately via SMS, phone, or another channel.
5
Send Your Email
A beautifully formatted secure download link is automatically inserted into your email. Send it like any normal email—your recipient clicks the link and instantly downloads the decrypted files. No account needed!
Passphrase Delivery Options
Choose how your recipient accesses the decryption passphrase:
Recommended
⚡ AutoLink
The passphrase is securely embedded in the download link using URL fragment technology. It never passes through our servers—your recipient simply clicks and downloads. Maximum convenience with zero compromise on security.
🔐 Manual Copy
The passphrase is copied to your clipboard for you to share through a separate channel like SMS, phone call, or in-person. Perfect for highly sensitive documents where you want an extra layer of verification.
Receiving Files via Client Portal
Need to receive sensitive files from clients? LockDoc provides a branded upload portal where clients can securely send you files—no account required on their end.
1
Share Your Portal Link
Each LockDoc account includes a personalized upload portal with your name. Simply share this link with clients who need to send you files securely.
2
Client Uploads Files
Your client enters their name and email, then drags and drops files or clicks to select them. Files can be any size or type—no limits.
3
Automatic Public Key Encryption
Files are encrypted on the client's device using your public RSA key before upload. This means only you can decrypt them—not even LockDoc can access the contents.
4
Email Notification
You receive an email notification when files are uploaded. Access your dashboard to view, decrypt, and download the files at your convenience.
Sending and Receiving Faxes
Some people still need a fax. Here's how faxing works in LockDoc:
1
Open Dashboard > Fax
Everything fax lives in your LockDoc dashboard: sending, your fax number, received faxes and moving your existing number.
2
Choose How to Send
Most secure: encrypted link (recommended when the recipient can open a link). LockDoc encrypts the PDF in your browser and faxes a cover page with a QR code and link. After sending, LockDoc shows you a passcode; give it to the recipient by phone or text. It is never on the fax.
Standard fax (the actual pages). The pages are faxed: encrypted on their way to our fax carrier, delivered over the phone network like any fax. LockDoc never keeps a readable copy.
3
Pick the Number and Recipient
Choose the number to send from (your LockDoc number, or LockDoc's shared number for pay-per-fax) and enter the fax number. You see the price before you send.
4
Send and Track
Click Send and follow the status until it shows Delivered. If a pay-per-fax send fails, it is refunded.
5
Receiving Faxes
Faxes to your LockDoc number appear in Dashboard > Fax and you get an email (without the fax). When you open the dashboard, your browser fetches each new fax, encrypts it to your key (or your team's key) and adds it to your encrypted inbox. The carrier's copy is then deleted.
6
Getting or Keeping a Fax Number
New number: search by area code or city, pick a number and confirm the monthly price (our cost). It is added to your subscription.
Keep your number: check that it can move, enter the details from your current phone bill, sign the letter of authorization in the app, upload a recent bill, and submit. Most numbers move in 1 to 3 weeks; you can use a temporary LockDoc number meanwhile. The details and the bill go to our phone carrier to process the transfer.
If your plan ends, your number stays for 14 days (we email you at the start and 3 days before release), then it is released.
Why Choose LockDoc?
Built for professionals who take security seriously.
True End-to-End Encryption
Your files are encrypted before leaving your device. We can't read your files—ever.
Works in Your Email
No new apps to learn. LockDoc integrates directly into Gmail and Outlook.
No Recipient Account Needed
Recipients simply click a link to download. No sign-up, no friction.
Unlimited File Size
Send large files that would be rejected by regular email attachments.
Works Everywhere
Available in 15+ languages with automatic detection of your locale.
Fast & Reliable
Modern infrastructure ensures your files are uploaded and available instantly.