Articles
The Flint PDF library
Short, practical pieces on PDFs — fixing a typo, signing a contract, getting a file under 25 MB, picking the right format, dealing with awkward scans. 965 articles and counting.
AES-256 PDF encryption explained
AES-256 is the cipher behind serious PDF security. A clear-eyed look at what it does and why compliance teams care.
4 minReadAre electronic signatures legally binding?
E-signatures are legally binding in nearly every developed jurisdiction. The exceptions are narrow and known.
4 minReadBrowser-based PDF security explained
Why browser-based PDF processing is often the cleanest security story. A technical and practical look.
5 minReadCCPA compliance for PDF tools
CCPA imposes data handling and disclosure obligations. PDF tool vendors are often service providers in scope.
4 minReadConsumer disclosure for electronic signatures
Consumer e-signing has extra rules. A short checklist of what to disclose.
4 minReadCorporate policy for online PDF tools
Free PDF tools are everywhere. A clear policy turns chaos into a manageable risk.
5 minReadDigital signature vs electronic signature: what's the difference?
Two terms that get used interchangeably — but mean different things in cryptography and law.
4 minReadDocument hash explained
Hashes are how PDFs prove they haven't been tampered with. A quick explainer.
4 minReadDropbox vs Flint for secure PDFs
Dropbox is great storage and sharing. Flint is the file-level security. They work together.
4 minReadeIDAS, explained
The European regulation that makes e-signatures portable across 27 member states.
5 minReadEncrypted email attachment vs secure link
Attachment vs link is a workflow choice. Here's when each beats the other.
4 minReadThe US ESIGN Act, explained
What the ESIGN Act actually says — and how it interacts with state law and UETA.
5 minReadEvidence of intent in electronic signatures
Intent is the legal core of every electronic signature. Here's what proves it.
4 minReadExpiring PDF links, explained
Time-boxed PDF access is one of the better defences against long-tail leaks. Here's how it works.
3 minReadGDPR compliance for PDF tools
PDFs often contain personal data. Treat online PDF tools as data processors and verify accordingly.
5 minReadHIPAA compliance for PDF tools
HIPAA requires Business Associate Agreements for any vendor processing PHI. PDF tools are no exception.
5 minReadHow courts look at electronic signatures
Courts have consistently upheld electronic signatures. Disputes turn on identity, not validity.
5 minReadHow long do online PDF editors keep your files?
Retention is the part of privacy policy people don't read. Here's the short version for common PDF tools.
4 minReadHow PDF tampering is detected
Tampering leaves traces. Here's how investigators and signing platforms catch alterations.
4 minReadHow to add a witness signature to a PDF
Witnessing is procedural — get the order and the presence right and the rest is mechanical.
4 minReadHow to add initials to a PDF
Initials per page is an old habit. Here's how to do it electronically without it taking forever.
3 minReadHow to add multiple signatures to a PDF
Co-founder agreements, deeds, partnership docs — here's how to fit several signatures on one PDF without breaking them.
3 minReadHow to avoid PDF tools that train AI on your files
Your sensitive PDF in a training set is forever. Here's how to keep yours out.
4 minReadHow to cancel a PDF signature request
Cancelling is cleaner than letting bad requests linger. Here's the process.
3 minReadHow to confirm redaction actually worked
Trust nothing, verify everything. The 30-second redaction verification process.
3 minReadHow to delete uploaded PDFs permanently
Delete-from-UI rarely means delete-from-everywhere. The honest workflow for permanent removal.
4 minReadHow to electronically sign a PDF in the EU
eIDAS makes e-signatures recognised across all 27 EU member states. The three-tier system explained.
5 minReadHow to electronically sign a PDF in the UK
What counts as an e-signature in the UK — and how to apply one to a PDF in a couple of minutes.
4 minReadHow to electronically sign a PDF in the US
ESIGN and UETA make e-signatures legally binding in all 50 states. Here's the workflow.
4 minReadHow to password-protect a PDF online
Lock down a PDF with a password in your browser — no installs, no accounts, no sketchy uploads.
4 minReadHow to password-protect bank statement PDFs
Bank statements have your account number, balance and address. Encrypt them before they leave your machine.
3 minReadHow to password-protect legal PDFs
Legal PDFs leak careers as well as cases. Lock them before they leave the matter folder.
4 minReadHow to password-protect medical record PDFs
Health records are the most regulated documents you'll ever email. Lock them properly.
4 minReadHow to password-protect payroll PDFs
Payroll PDFs leak more than you think. Lock them before they leave the finance team.
3 minReadHow to password-protect tax document PDFs
Tax documents are identity-theft starter packs. A password is the minimum before forwarding them.
3 minReadHow to properly redact a PDF
A black rectangle isn't redaction. Here's the proper way to remove sensitive content from a PDF.
5 minReadHow to protect a confidential PDF
Confidentiality is layered. Here's the order of operations for documents that genuinely matter.
5 minReadHow to read a PDF audit trail
Audit trails look intimidating. They're easy to read once you know what each line means.
4 minReadHow to recover a PDF password you forgot
There's no magic key — but there are sensible places to look before declaring a PDF dead.
4 minReadHow to redact a PDF for court
Redacting for litigation is different from redacting for casual sharing. The bar is higher.
5 minReadHow to redact a PDF for public release
Public release means anyone can probe the redactions. Make sure they hold.
5 minReadHow to redact credit card numbers in PDFs
PAN exposure is a PCI-DSS violation in commercial settings. Redact card numbers before sharing.
3 minReadHow to redact medical record numbers in PDFs
Medical record numbers are HIPAA-protected identifiers. Redact before any external sharing.
4 minReadHow to redact Social Security Numbers in PDFs
SSNs are the most stolen identifier in the US. Redact them properly before sharing.
3 minReadHow to redact a PDF with OCR
Scanned PDFs are images. Redaction needs OCR first to find the text to remove.
4 minReadHow to remove a password from a PDF you own
You set the password months ago and now it's just friction. Here's how to remove it cleanly.
3 minReadHow to request signatures from multiple people
Multi-party signing is a workflow problem more than a signing problem. Here's how to structure it.
4 minReadHow to resend a PDF signature request
Resending is usually a one-click action. Here's when to do it and when to do something else.
3 minReadHow to revoke access to a shared PDF
Revocation is harder than it sounds with PDFs. Here's what actually works.
4 minReadHow to send a PDF for signature
Skip the email-print-sign-scan loop. Send the PDF directly for in-browser signing.
3 minReadHow to set a strong PDF password
Most PDF passwords are too short to matter. Here's how to set one that actually does its job.
4 minReadHow to set up signing order in a PDF
When the order of signatures matters, set it explicitly. Here's how — and why.
3 minReadHow to share a confidential PDF with employees
Internal doesn't mean unprotected. Here's the discipline for confidential employee communications.
4 minReadHow to share a password-protected PDF safely
A password sent in the same email as the PDF is no password at all. The simple rules of safe distribution.
3 minReadHow to share a PDF securely by email
Email forwards forever. Here's how to send a PDF in a way that survives a forward you didn't intend.
4 minReadHow to share a PDF with a client
Client-bound PDFs need both confidentiality and professionalism. Here's the workflow.
4 minReadHow to share a PDF with an accountant
Your accountant gets the most sensitive financial documents you own. Encrypt them first.
3 minReadHow to share a PDF with an attorney
Privileged doesn't mean uninterceptable. Send PDFs to your lawyer through channels that hold up.
4 minReadHow to share a PDF with HR
HR receives the most sensitive employee documents. Encrypt before sending; never include passwords in the email.
3 minReadHow to share a PDF with view-only access
True view-only requires a hosted viewer. PDF permissions are a partial substitute.
4 minRead