Electronic Signature Verification and .p7m Opener

Online tool for verifying electronic signatures and opening .p7m, .p7s, .sig and .asice files. It shows who signed a document and when, whether the file changed after signing, and whether the certificate came from a qualified trust service provider; a PDF, an XML invoice or an email opens right on the page. It checks RSA, ECDSA and GOST signatures in CMS, PDF, XML and ASiC containers.

How to verify an electronic signature

Drop the files

Everything you received: signature and document, an archive, a signed PDF or a container.

Read the answer

Who signed, when, whether the document changed, whether the certificate was valid and who issued it.

Open the document

The PDF, XML or email opens right here; a document wrapped in a .p7m can be downloaded.

Save the report

A PDF with the certificate fields, fingerprints and hashes.

Check a signature and open the signed document

Drop everything you were sent hereAdd files

Signature and document together or one at a time, an archive, a signed PDF or a container — the type and the pair are detected automatically.

Choose files

Signature as text (Base64 or PEM)

The cryptographic check runs in your browser. To check the issuer and revocation, the site requests the list of trust providers and the revocation list at the address given in the certificate.

What you will learn

Who signedName, title, organization and identifiers from the certificate.
WhenThe time claimed by the signer, or confirmed by a timestamp.
Whether the document changedThe document hash is compared with the signed one; edits made after signing show up.
Who issued the certificateThe issuer against the EU Trusted Lists or the Russian accredited CA list — as of the issue date.
The document itselfA PDF, an XML invoice, an email — opened right here, no software needed.
Verification reportA PDF with the certificate fields, fingerprints and hashes.

No file at hand? Try an example

This is a cryptographic check, not a legal opinion. For court, a qualified signature is validated by a qualified validation service. EU validation tool

Features

One drop for everything

An .xml.p7m invoice, a Base64 .p7m and a double-wrapped .p7m.p7m, an .asice or .bdoc container, a signed PDF, a ZIP inside a ZIP, an email: the type and the pair are found on their own, and the document for a detached signature is matched by its hash.

Trust as of the issue date

The issuer is checked against the EU Trusted Lists (and the Russian accredited CA list) as of the day the certificate was issued — a certificate that expired after signing is normal.

Revocation and signing time

The issuer’s CRL or OCSP and validation data embedded in the signature; a time stated by the signer is told apart from one confirmed by a timestamp.

XAdES, CAdES, PAdES, ASiC

XML signatures with their transforms, CMS with countersignatures and archive timestamps, every signature in a PDF and the files of a container — including any file the signature does not cover.

The document on screen

A PDF page by page, XML as a readable table, and the signed version of a PDF edited after signing as a separate download.

PDF report

Every certificate field, SHA-1 and SHA-256 fingerprints, document hashes and each check — as real, searchable text.

Frequently asked questions

How do I open an .xml.p7m invoice without installing software?

Drop the .p7m here. The invoice is stored inside the signature, so it is checked and extracted in one go, and the XML is shown as a readable table. Base64 files and double-wrapped .p7m.p7m files are unwrapped automatically.

The certificate has expired. Is the signature still valid?

Yes, if the certificate was in effect when the document was signed. The validity period is therefore checked twice: at signing time and today. A signing time confirmed by a timestamp is the strongest proof; a time without one was stated by the signer’s own computer, and the answer says so.

What does “the document changed after signing — or the signature belongs to another file” mean?

The hash of the file you added differs from the hash recorded in the signature. Either the file was edited after signing (even re-saving changes the bytes), or the signature was made for another version of the document. If you drop several files, each one is compared with the signature and the real pair is found automatically.

Why does my .asice container say a file is not covered by the signature?

Every file in an ASiC container must be listed in a signature or its manifest. A file that is in the ZIP but not in any signature was not signed — often it was added to the container afterward. The signed files themselves can still be valid, and the list shows which file is which.

The PDF has a “digitally signed” stamp. Is that a signature?

A stamp is an image or text on the page, and anyone can draw one. A real signature is cryptographic: embedded in the PDF or delivered as a separate file. If there is none, the answer says so: “the PDF only shows a picture of a stamp”.

Does “qualified” here mean the signature is legally valid?

It means the issuer was a qualified trust service provider on the EU Trusted List when the certificate was issued, and the certificate declares itself qualified. That is a strong technical indicator, not a legal ruling: for court, signatures are validated by a qualified validation service.

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Published 21 Oct 2026 Updated 23 Oct 2026 Author: The Supreme