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Windows Font Preview tool sometimes says: "Digitally signed" for a font. According to Adobes website, this means:

If the digital signature is valid, then the font really was made by the font foundry identified in the DSIG table.

The Font Preview tool does not say anything about "font foundry". Even the Details-view (right click/properties) in Windows Explorer on a font file does not say anything about "font foundry", it only has the usual other metadata like "Author", "Copyright", "Trademark" etc, but I could not find any valid pattern about which of those metadata actually is signed by the signature.

And how can I check if the signature is still valid, or what the signature even looks like (VeriSign etc)?

Different to .exe files, font files don't have a "Digital Signature" tab when right clicked on. This is so confusing. I also did not find any program that could display infos about the font signatures.

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up vote 1 down vote accepted

Download Microsoft's font signing tool. Run the executable and tell it to unpack in an empty directory. From a command prompt, cd to the directory you unpacked the tool in and register the font signing tool with regsvr32 mssipotf.dll. Then you can look at a font's signature in detail by running the included chktrust tool. Click on the publisher's name and then View Certificate.

Update: On Windows 7, you need to register mssipotf.dll from an elevated command prompt.

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Sadly, this does not work. I have Windows 7 64bit and when i run chktrust on a MinionPro.otf for example (or any other signed font i tested), I get a Security Warning featuring: FontName: MinionPro and Publisher: Unknown Publisher. And i must choose: Execute or NotExecute. Doesnt matter what option i choose, nothing happens. – Jürgen Halbesmaß Jan 1 '13 at 19:52
If you get an "Unknown Publisher" then the font is not digitally signed. Try it on agencyr.ttf which is digitally signed by Microsoft. If that still doesn't work, then you didn't register mssipotf.dll from an elevated command prompt. – David Schwartz Jan 1 '13 at 20:09
Windows Font Preview tells me my fonts are signed (Originals from Adobe application by the way), but anyway, I downloaded the font you mentioned from the internet, Font Preview tells me its signed, but still, chktrust only gives the Security Warning and Unknown Publisher. On the commandline, chktrust ends with "Succeeded." I registered the .dll beforehand successfully too. – Jürgen Halbesmaß Jan 1 '13 at 20:19
It will succeed even if you don't register it from an elevated command prompt, and it won't work. If you are sure you registered it from an elevated command prompt, then I'm out of ideas. It works for me, on Windows 7 64-bit. – David Schwartz Jan 1 '13 at 20:25
Okay i found the answer: the mssipotf.dll file must reside in a searchpath folder. copy it to syswow64 for example or in same directory like the font file. only then it works. thanks for the infos. – Jürgen Halbesmaß Jan 1 '13 at 20:39

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