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Protect PDF Cluster

Secure Business PDF — Zero-Knowledge Protection

Finance and legal should not upload invoices to a consumer converter in order to password them. Instant Protect encrypts in the tab. Forwarding risk remains: anyone with the passphrase can open and screenshot. Redact fields they should never see even after unlock. Do not put the password in the same email as the attachment.

Batch-protecting multiple business PDFs or securing massive 100MB+ archives requires Pro. Upgrade via Lemon Squeezy for enterprise-scale encryption workflows.

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

Company PDFs, local crypto, honest limits

Invoices, contracts, board financials, discovery exhibits. Same AES/RC4 pdf-lib path. If DLP forbids browsers, stop. If DLP forbids unknown SaaS processors, Instant is the better fit than an upload locker.

Email forwarding

A locked PDF still forwards. The passphrase is the gate. Rotate it if the wrong person received it. Keep unlocked masters in your records system, not in the same inbox.

Huge archives

100 MB+ and folder-scale locks are Premium. The crypto is still local pdf-lib, not a VPS OCR job.

Employees who forget

No recovery. Internal procedure: retain an unlocked original in a vault you already trust.

How it works

  1. 1

    Load the business PDF locally

    Web Worker. Zero transmission.

  2. 2

    Apply encryption

    Strong unique passphrase. AES/RC4 via pdf-lib.

  3. 3

    Export

    Standard singles free. Batch and huge archives Premium.

Use cases

Invoices with line-item pricing

Lock before email so casual forwarding still needs the phrase.

Contract drafts

Named counterparties get the passphrase separately.

Board packets

Financial sections locked before a portal that lacks native encryption.

Counsel handoff

Encrypt locally, then use your existing secure channel.

Problems we solve

Policy vs random servers

Instant never sends PII to us.

Open attachments spreading

Password first, then send.

Browser memory on 200 MB packs

Premium exists for that scale.

Trust & privacy

Zero-knowledge

We never see bytes or passwords.

Spec encryption

AES/RC4 per PDF.

No retention clock

Nothing stored, so nothing to delete on our side.

Frequently asked questions

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