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Protect PDF Cluster

Secure PDF for Sharing — Lock Before Send

About to drop a contract in Gmail or a public Dropbox link? Lock it first on this machine. Recipients need a normal PDF reader plus the passphrase. Anyone with the link to an unlocked file can download it — the password is the extra gate. Never put that gate in the same email as the attachment.

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Written by Safaat Rahman Siham, Founder & Developer at Convertify4u. Contact us.

Lock, then share, then tell them the secret elsewhere

Email in transit is often not a vault. Cloud links sprawl. Instant Protect adds an open password before either hop. It does not make Slack a secure messenger. It does not stop screenshots. Redact if the recipient should never see a field even after they unlock.

Out-of-band password

SMS, phone, Signal, a password manager share — pick one that is not the inbox you used for the PDF.

Drive and Dropbox

A public link plus an unlocked PDF is just a download. Encrypt first. Then the link is less fatal if it leaks.

Portals without encryption

Vendor sites that accept PDFs but do not encrypt at rest still benefit from an open password on the file itself.

How it works

  1. 1

    Open the attachment locally

    Worker loads pages. No server contact.

  2. 2

    Set a share password

    You will send it separately. AES/RC4 via pdf-lib.

  3. 3

    Send the locked file

    Email, link, or portal. Phrase on another channel.

Use cases

Tax forms over email

If the message is intercepted, the attachment still asks for a password.

Public cloud links

Lock, then create the Drive link.

Vendor portals

When they have no native encryption.

Offer letters

HR PDF plus passphrase via a second channel.

Problems we solve

SMTP in the clear

Lock the payload.

Anyone-with-the-link

Password-lock first.

Upload-then-encrypt services

They held a copy. We never did.

Trust & privacy

Lock before first send

No server copy of your attachment.

Standard readers

Acrobat, Preview, Chrome — plus your password.

Free typical shares

Huge files Premium.

Frequently asked questions

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