The Story

One of my friends has some dealings with the Israeli courts.
The noteworthy (and annoying) part of their digital documents is that these documents are using a novel format instead of some industry standard.
Files arriving by email have the SGN suffix, and the email includes the following footer:

המסמך המצורף חתום דיגיטלית. כדי לצפות בקובץ יש להוריד תוכנה בכתובת : Digital Signature Application.msi
)התוכנה תואמת למערכת הפעלה Windows בלבד(

English Google translation:

The attached document is digitally signed. To view the file you need to download software at: Digital Signature Application.msi
) The software is compatible with Windows operating system only (

This friend doesn't have Windows, so how can he read those docs?

My solution

From taking a peek in the doc, I saw that it's basically a ginormous XML, with fields containing the following:

  1. Original filename
  2. Content, encoded as base64
  3. Signer identity

I was willing to skip verifying the signer, and settled instead for just extracting the original file.
THe quick solution is:

xq -r '.DocumentEnvelope.SignaturePackage.Signature.Object.DocumentContent["#text"]' | base64 --decode

xq is a jq-like command for XML. It has a YAML equivalent as well, and was highly useful here.
base64 is a bash utility for decoding/encoding base64 data.

I made a nicer version in my sgn-court-extract repo. I might migrate it to a proper Python script one day.

Feel free to use it yourself!


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