OFD documents

SumatraPDF opens OFD (.ofd), the Chinese fixed-layout document format (GB/T 33190) used for e-invoices and government documents, and checks its signatures. This page lists what works and how it compares with other OFD software.

Available in pre-release 3.7.

Open an .ofd file like a PDF: double-click it, drag it onto the window or use File → Open. At a glance:

Pages: text, paths, images, templates, annotations, patterns, gradients (including mesh gradients) and signature seals are drawn natively, with no conversion to PDF.
Packages: an OFD with several documents shows all of them in order, with a bookmark for each.
Encrypted OFD: a password-encrypted package (GM/T 0099) asks for the password, as an encrypted PDF does.
Text: select, copy and find text; embedded fonts keep their original characters.
Links and attachments: click links to other pages or to web sites; attachments are listed under the bookmarks and open like PDF attachments.
Signatures: the signature bar and the Signatures view show whether each signature is valid, as for signed PDFs.
Convert: Convert to PDF keeps text and vector graphics; Convert PDF to Images renders OFD pages too.
Printing: print any pages.
File Explorer: the installer registers .ofd for Open With and adds previews and thumbnails.

Open an OFD file #

Double-click an .ofd file once SumatraPDF is registered for it, or right-click → Open with → SumatraPDF.
An OFD renamed to .zip, or attached to a PDF as .zip, still opens as OFD.
For a password-encrypted OFD, type the password when asked, or pass it with -pwd. A package encrypted for a certificate (it needs the recipient’s private key) can’t be opened.
The bookmarks sidebar shows the document’s outline. For a package of several documents it shows one entry per document, with that document’s outline under it.

Note: missing fonts are replaced, and a broken image or template is skipped without losing the rest of the page.

Check OFD signatures #

Opening a signed OFD checks its signatures in the background. The bar above the document says whether they are valid. Click Signature Panel for the list, and open a signature for its details.

SumatraPDF checks electronic seals (SES, GM/T 0031 v1 and v4, GB/T 38540) and GB/T 35275 digital signatures that use SM2 and SM3:

the files the signature protects still have the digests it recorded
Signature.xml matches the hash inside the signature
the signature matches the signer’s certificate, and the certificate was valid at the signature time
the signer’s certificate chains to a trusted root

A package with integrity protection (GM/T 0099, OFDEntries.xml) shows it as one more entry. It is invalid when a file was added to the package or removed from it after it was protected.

Results:

Valid: the document is unchanged and the signer’s certificate chains to a trusted root.
Invalid: a signed file was changed or removed, a file was added to a protected package, or the signature doesn’t match the certificate.
Validity unknown: the document is unchanged, but the certificate doesn’t chain to a trusted root. A signature without a certificate, or with an unsupported algorithm, can’t be checked either.

Trust OFD signers #

Windows doesn’t check SM2 certificates, so SumatraPDF does: a signer is trusted when its certificate chains, through certificates in the Windows Intermediate Certification Authorities store, to a certificate in the Windows Trusted Root Certification Authorities store or in the OfdTrustedCertificates advanced setting.

To trust a CA without adding it to Windows:

Open Settings → Advanced Settings…
Set OfdTrustedCertificates to the path of the CA’s certificate file, DER or PEM. Separate several paths with spaces and quote paths that contain spaces: OfdTrustedCertificates = "C:/certs/my ca.pem" C:/certs/other.cer
Reopen the document.

Note: a seal drawn on the page proves nothing by itself. Check the status in the bar or the Signatures view.

Compare with other OFD software #

	SumatraPDF	ofdrw	ofdrw-viewer	ofd.js
What it is	Windows document viewer	Java library	HTML5 reader, rendering engine, command-line tool	JavaScript rendering library
License	GPLv3	MIT	MIT	Apache-2.0
View and print	✓	via conversion to PDF or images	✓	renders in a web page
Viewer with bookmarks and text search	✓		✓
Encrypted OFD (GM/T 0099)	✓ decrypt (password)	✓ encrypt	✓ decrypt
Verify SM2 / SM3 signatures	✓	✓	✓
Certificate chain and trusted roots	✓		✓
Detect files added after signing	✓		✓
Create, edit, sign, merge		✓
Convert PDF to OFD, OFD to PDF or images	OFD to PDF or images	✓	OFD to images

An empty cell means the project doesn’t document the feature.

Popular desktop readers in China, all closed source and free to use:

数科OFD阅读器 (Suwell, ofd.cn): Windows and Linux; views, prints and verifies electronic seals, saves as PDF or images.
福昕OFD阅读器 (Foxit OFD Reader): desktop and mobile; views, annotates, shows the outline and prints.
WPS Office: opens OFD on Windows (2021 update and later), Android and iOS; views, annotates and saves as PDF.

Tips #

Use SumatraPDF to read and print OFD invoices without installing a dedicated OFD reader.
Open a signature’s details to see which file was changed when a signature is invalid.
Add your CA’s certificate to OfdTrustedCertificates so its signatures show as valid.
Use ofdrw to create, sign or edit OFD files.
If a page doesn’t look right, report it with the .ofd file.

What SumatraPDF doesn’t do #

edit, create or sign OFD files, or convert PDF to OFD
open packages encrypted for a certificate
check signature timestamps
annotate OFD files