P7M / CAdES Signature Opener
Someone sent you a .p7m file and nothing on your computer will open it. Drop it here: this pulls the original document (an invoice XML, a PDF, anything) back out of the digital-signature wrapper and shows you who signed it - without installing signature software and without uploading your file anywhere.
What a .p7m file actually is
A .p7m file isn't a document format of its own - it's an envelope. The format is PKCS#7 / CMS “SignedData” (RFC 5652), and in the European CAdES profile it wraps your real document together with a digital signature and the signer's certificate. That's why the filenames stack up like fattura.xml.p7m or documento.pdf.p7m: the inner extension tells you what's inside, and the .p7m tells you it has been signed.
This tool reads that envelope with a real BER decoder, which matters more than it sounds: plenty of production p7m files use indefinite-length BER encoding with the document split across multiple segments, and a simpler DER-only reader quietly corrupts the extracted file. Base64-armoured files, files signed more than once (an envelope inside an envelope), and detached signatures are all handled and clearly labelled.
Questions fréquentes
Come aprire un file p7m online gratis?
Trascina il file .p7m nel riquadro qui sopra. Lo strumento apre la busta crittografica PKCS#7/CAdES direttamente nel browser, estrae il documento originale - una fattura XML, un PDF o qualsiasi altro file - e te lo fa scaricare con l'estensione corretta, riconosciuta dal contenuto reale del file. Ti mostra anche chi ha firmato: nome e cognome del firmatario, organizzazione, codice fiscale contenuto nel certificato, ente certificatore e date di validità. È gratuito, non richiede installazione e il file non viene mai caricato su un server.
È un visualizzatore di fattura elettronica XML p7m?
Apre la busta p7m ed estrae la fattura elettronica XML che contiene, mostrandoti anche un'anteprima del contenuto e segnalando quando riconosce una FatturaPA italiana. Per leggere la fattura come un documento normale - con venditore, acquirente, righe, IVA e totale - scarica l'XML estratto e aprilo nel nostro visualizzatore di fatture elettroniche, che supporta i formati FatturaPA-adiacenti, UBL e CII.
¿Cómo extraer el archivo de un p7m?
Sube el archivo .p7m a la herramienta de arriba y pulsa "Download the original file". Un .p7m es un sobre PKCS#7/CAdES que envuelve el documento real junto con la firma digital y el certificado del firmante; la herramienta abre ese sobre y te devuelve el documento original intacto, byte por byte. Detecta automáticamente si dentro hay un XML, un PDF, un ZIP o una imagen y le asigna la extensión correcta, incluso si el nombre del archivo original se había perdido. Todo ocurre en tu navegador.
Does this verify that the digital signature is valid?
No, and it's important to be clear about that. This tool reads the structure of the signature envelope and reports what is recorded inside it. It does not recompute the document's message digest, does not check the signature value against the signer's public key, does not build or validate a certificate chain up to a trusted root, and does not check revocation via CRL or OCSP. When it says a certificate is "within its validity window", that means only that the dates written inside the certificate bracket the date being compared - nothing more. For a legally meaningful verification you need an accredited validation service, such as your national trust-list validator or the EU DSS demonstration tool.
What information about the signer can I actually see?
Everything recorded in the signer's certificate: common name (usually the person's name), organisation and organisational unit, country, the certificate's serial-number field - which in Italian and Spanish qualified certificates carries the holder's fiscal code or national ID - the certification authority that issued it, and the validity dates. Alongside that you get the signature's own details: the CAdES form (BES, T, C or A), the declared signing time, and the digest and signature algorithms used. The tool also tells you whether the certificate was inside its validity window at the moment of signing, which is often more meaningful than whether it is still valid today.
Is my file uploaded to a server?
No. The whole ASN.1 parse - opening the envelope, reading the certificates, extracting the original document - runs locally in your browser using JavaScript. Signed files routinely contain invoices, contracts and personal identifiers, so nothing is transmitted, logged or stored. You can verify this by disconnecting from the internet once the page has loaded; the tool keeps working.
Why does it say "detached signature" with nothing to download?
Because some signatures are stored separately from the file they sign. In a detached signature the envelope carries only the signature and the certificates, and the signed document travels next to it as an ordinary separate file. There's genuinely nothing inside to extract in that case - but the signer and certificate details still display normally, so you can see who signed the accompanying document.
My file is called something.p7m.p7m - will that work?
Yes. Files sometimes get signed more than once, producing one signature envelope nested inside another. The tool peels every layer automatically until it reaches the real document, tells you how many signature layers it found, and lists the details of each one separately so you can see every signer.
Which file types can come out of a .p7m?
Any of them - the envelope doesn't care what it wraps. The extracted content is identified from its actual bytes rather than from the filename, so XML, PDF, ZIP, JPEG, PNG, RTF, legacy Office documents and plain text are all recognised and given the right extension. Anything unrecognised is offered as a .bin download so you never lose the data.