How to read a .P7M file online
Three steps, a few seconds.
Open your .P7M file
Drop it on the box or click to choose it. A bundle holding several certificates is split for you automatically.
Unlock if needed
A password-protected file asks for its export password. It is used only to unlock the file.
Check the details
Read the chain from your certificate up to the root, see every domain it covers, when it expires and copy its SHA-256 fingerprints.
What is a .P7M file?
What's inside .crt, .pem and .p12 files, in plain words.
A .p7m file is a PKCS#7/CMS container that wraps an original document, usually a PDF or XML e-invoice, together with a digital signature and/or encryption. To open it, use DiKe (InfoCert), Aruba Sign, Adobe Acrobat (PDF case), or OpenSSL; a plain text editor or simple rename to .pdf will not work because the document is still wrapped inside.
Programs that open .P7M files
| Full name | PKCS#7 / S/MIME Message (digitally signed or encrypted) |
|---|---|
| Developer | RSA Security (PKCS#7) / IETF (S/MIME, CMS — RFC 5652) |
| First released | PKCS#7 (1990s); S/MIME / CMS standardized in RFC 5652. Heavily used for EU/Italian legal e-signatures (CAdES) |
| Category | Data & Other |
| MIME type | application/pkcs7-mime |
| Signature | 30 82 (DER-encoded: begins with ASN.1 SEQUENCE 0x30 0x82 (length) at offset 0. Base64-armored variant is text starting "MII...".) |
Related viewers
Other free tools to open and preview your files.
Frequently asked questions
Is it safe to open my .P7M file here?
Yes. Certificates are public by design, and decoding and signature checks run with the Web Crypto API.
What does “chain verified” mean?
Each certificate is signed by the one above it. The viewer checks those signatures mathematically, so you can see whether your server certificate, intermediate and root actually belong together - the most common cause of “incomplete chain” errors.
My .p12 / .pfx asks for a password. Which one?
The password chosen when the file was exported (for example from Windows, a browser or your CA's portal). Some files have an empty password - try leaving the field blank.
Why don't you show my private key?
A private key is the secret half of the certificate. Anyone who sees it can impersonate you, so the viewer only tells you that a key is present and what type and size it is.
Can it check if a certificate is revoked?
Not yet. Revocation (OCSP/CRL) needs to contact the certificate authority, which we keep for the server-side version of this tool.
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