BIZSEAL guide
How to open a .p7m file without installing anything
A .p7m file is a document wrapped in a digital signature. The signature and the document travel together in one envelope, and the operating system does not know how to open that envelope. A reader that understands the format can unwrap it and show you both parts.
What is inside a .p7m file
The file holds three things: the original document, one or more signatures, and the certificate of each signer. The name usually tells you the original type: contract.pdf.p7m holds a PDF, invoice.xml.p7m holds an XML file. Remove the .p7m ending and you have the name of the document inside.
Why it will not open
Windows, macOS, iOS and Android have no built-in program for this kind of signed envelope. Double-clicking the file either does nothing or opens a program that shows unreadable characters. Renaming the file does not help, because the document is still inside the envelope.
Reading it without uploading it
Many online readers ask you to upload the file to their server. A browser reader can do the same work on your device instead: the page loads once, and the file is read in the browser without being sent anywhere. That matters when the document is a contract, an invoice or a court paper.
In the free BIZSEAL reader you choose the file, and the page shows the signer, the certificate details, whether the signature matches the content, and a button to download the original document.
What the reading tells you
- Who signed: the name, organisation and country in the signer's certificate.
- Who issued the certificate and the dates it covers.
- The signing time the signer stated. It comes from the signer's own computer, so treat it as a claim.
- Whether the signature matches the content: if one byte of the document had changed, the check would fail.
- The SHA-256 of the file, a fingerprint you can note down to show which file you read.
What it does not tell you
A reading in the browser does not confirm legal validity. That needs three more checks: that the certificate chains to a trust service provider on an official trust list, that it was not revoked, and that it was valid at the signing time. Your certificate provider's verifier, or the one your court or tax office names, does those checks.
Common questions
Is it safe to open a .p7m file?
The file holds a document and a signature, like any attachment. Open it only if you expected it, and treat the document inside with the same care as any file you receive.
Can I get the PDF out of a .p7m?
Yes. If the document inside is a PDF, the reader offers it as a download with its original name, for example contract.pdf.
Does the free reader keep my file?
No. The reader runs in your browser. The file is not uploaded, stored or logged.