Microsoft Word and digital signatures using PGP?

Question

I have a document for a project that I am working on with my team, and I need to digitally sign the document in a way that can be verified by other members of the team. The catch is, internally, we are using PGP (the commercial version, I think). It appears that, for all intents and purposes, PGP is wholly incompatible with any of Microsoft Office's built-in digital signature functions. Ditto for Adobe Acrobat.This is baffling, because PGP is a defined RFC, 4880, so I would imagine that it is possible for MS to integrate SOME kind of support for either X.509 or PGP. Signing a document using the external PGP software, however, produces a stand-alone .sig file that has to tag along with the original document for anyone to be able to verify its authenticity. Since I have multiple people that need to digitally sign this document, I have no idea if this means I would need to manage one .sig for each signee, or if a single .sig file can hold multiple signatures by different signees.Is there a solution of some kind that can allow me to digitally authenticate/verify Word or PDF documents using PGP keys amongst members of a team? It'd be great if there is something that can leave a visual mark within the document itself, too.I figured that if there was a way to export an X.509/PKCS-12 certificate based off of a public PGP key, and then store that certificate in Windows' internal certificate store (`certmgr`), then maybe I could get Office to pull from that. But this appears to be impossible. I mean, aren't both technically bog-standard PKI certificates? Assume that each signee has their own PGP keypair with passphrase and that there is an internal PGP keyserver that everyone can sync to.Thoughts?

Answer 1

You're absolutely right — PGP (OpenPGP, RFC 4880) and Microsoft Office's native digital signature tools (which rely on X.509 and PKCS#12 certificates) don't play well together. They operate under different Public Key Infrastructure (PKI) models:

1. PGP is web-of-trust based and uses its own signature and encryption mechanisms.
2. Office and Adobe Acrobat use X.509 certificate-based PKI (certificate chains, trust hierarchies).

The Problem (as you've diagnosed well)

1. Signing a .docx or .pdf with PGP externally produces a detached .sig file, which:
2. Is not embedded in the document.
3. Isn’t verifiable within Word or Acrobat.
4. No native PGP plugin exists for Word or Acrobat.
5. Converting PGP → X.509 (PKCS#12) isn’t directly possible, as the formats and trust models are fundamentally different.

Option 1: Detached PGP Signatures + Checksum Management

While clunky, this is the most PGP-native solution:

1. Each signer runs gpg --detach-sign on the document.
2. You get:
3. document.docx
4. document.docx.sig (Alice)
5. document.docx.bob.sig (Bob)
6. Use a central checksum/signature manifest file or bundle.
7. Optionally: create a .zip file or a Git repo of:
8. Original doc
9. All .sig files
10. A README or signed manifest listing who signed what.

Pros: Standards-compliant, secure, and doesn’t rely on Microsoft or Adobe

Cons: No visual cues in the document itself; needs external tooling

Option 2: Convert to PDF and Use PGP-Capable Tools

1. Convert the Word document to PDF.
2. Use a tool like:
3. GnuPG with GPA or Kleopatra (Windows GUI for GnuPG)
4. Qubes + Split GPG (advanced setup)
5. Open-source apps like signify, OpenPGP.js, or GPGTools (macOS)

You can annotate the PDF with visual signature info, then sign the whole PDF file with your PGP key.

Team members then sign the same file, producing multiple .sig files. Again, these can be collected in a signed manifest or included in a ZIP bundle.

Option 3: Use git + git-crypt or signed commits

If your team uses Git:

1. Store the document (Word or PDF) in a Git repo.
2. Team members sign Git commits or tags with their PGP keys.
3. git commit -S -m "Signed by Alice"
4. You get PGP-signed change history, and it’s tamper-evident.

Pros: Clean, auditable, modern

Cons: Not visual inside the document, may require Git fluency

Option 4: PDF PGP-Signature Embedding via Custom Tools

1. Some workflows generate PDFs with visible fields saying “Digitally signed by Alice (PGP key ID)”.
2. You can:
3. Annotate the PDF with visible PGP signature blocks.
4. Use gpg --clearsign on a hash or summary of the PDF.

Recommended Hybrid Approach for Now

StepTool
1. Finalize document	MS Word / Export to PDF
2. Add visual signature placeholder (name, key ID, etc.)	Word/Adobe
3. Each person signs using gpg --detach-sign	GnuPG / PGP
4. Create a ZIP or folder with document + all .sig files	Shared location or repo
5. Optionally sign the ZIP itself	gpg --sign archive.zip

Answer 2

You're absolutely right — PGP (OpenPGP, RFC 4880) and Microsoft Office's native digital signature tools (which rely on X.509 and PKCS#12 certificates) don't play well together. They operate under different Public Key Infrastructure (PKI) models:

1. PGP is web-of-trust based and uses its own signature and encryption mechanisms.
2. Office and Adobe Acrobat use X.509 certificate-based PKI (certificate chains, trust hierarchies).

The Problem (as you've diagnosed well)

1. Signing a .docx or .pdf with PGP externally produces a detached .sig file, which:
2. Is not embedded in the document.
3. Isn’t verifiable within Word or Acrobat.
4. No native PGP plugin exists for Word or Acrobat.
5. Converting PGP → X.509 (PKCS#12) isn’t directly possible, as the formats and trust models are fundamentally different.

Option 1: Detached PGP Signatures + Checksum Management

While clunky, this is the most PGP-native solution:

1. Each signer runs gpg --detach-sign on the document.
2. You get:
3. document.docx
4. document.docx.sig (Alice)
5. document.docx.bob.sig (Bob)
6. Use a central checksum/signature manifest file or bundle.
7. Optionally: create a .zip file or a Git repo of:
8. Original doc
9. All .sig files
10. A README or signed manifest listing who signed what.

Pros: Standards-compliant, secure, and doesn’t rely on Microsoft or Adobe

Cons: No visual cues in the document itself; needs external tooling

Option 2: Convert to PDF and Use PGP-Capable Tools

1. Convert the Word document to PDF.
2. Use a tool like:
3. GnuPG with GPA or Kleopatra (Windows GUI for GnuPG)
4. Qubes + Split GPG (advanced setup)
5. Open-source apps like signify, OpenPGP.js, or GPGTools (macOS)

You can annotate the PDF with visual signature info, then sign the whole PDF file with your PGP key.

Team members then sign the same file, producing multiple .sig files. Again, these can be collected in a signed manifest or included in a ZIP bundle.

Option 3: Use git + git-crypt or signed commits

If your team uses Git:

1. Store the document (Word or PDF) in a Git repo.
2. Team members sign Git commits or tags with their PGP keys.
3. git commit -S -m "Signed by Alice"
4. You get PGP-signed change history, and it’s tamper-evident.

Pros: Clean, auditable, modern

Cons: Not visual inside the document, may require Git fluency

Option 4: PDF PGP-Signature Embedding via Custom Tools

1. Some workflows generate PDFs with visible fields saying “Digitally signed by Alice (PGP key ID)”.
2. You can:
3. Annotate the PDF with visible PGP signature blocks.
4. Use gpg --clearsign on a hash or summary of the PDF.

Recommended Hybrid Approach for Now

StepTool
1. Finalize document	MS Word / Export to PDF
2. Add visual signature placeholder (name, key ID, etc.)	Word/Adobe
3. Each person signs using gpg --detach-sign	GnuPG / PGP
4. Create a ZIP or folder with document + all .sig files	Shared location or repo
5. Optionally sign the ZIP itself	gpg --sign archive.zip

Answer 3

You're absolutely right — PGP (OpenPGP, RFC 4880) and Microsoft Office's native digital signature tools (which rely on X.509 and PKCS#12 certificates) don't play well together. They operate under different Public Key Infrastructure (PKI) models:

1. PGP is web-of-trust based and uses its own signature and encryption mechanisms.
2. Office and Adobe Acrobat use X.509 certificate-based PKI (certificate chains, trust hierarchies).

The Problem (as you've diagnosed well)

1. Signing a .docx or .pdf with PGP externally produces a detached .sig file, which:
2. Is not embedded in the document.
3. Isn’t verifiable within Word or Acrobat.
4. No native PGP plugin exists for Word or Acrobat.
5. Converting PGP → X.509 (PKCS#12) isn’t directly possible, as the formats and trust models are fundamentally different.

Option 1: Detached PGP Signatures + Checksum Management

While clunky, this is the most PGP-native solution:

1. Each signer runs gpg --detach-sign on the document.
2. You get:
3. document.docx
4. document.docx.sig (Alice)
5. document.docx.bob.sig (Bob)
6. Use a central checksum/signature manifest file or bundle.
7. Optionally: create a .zip file or a Git repo of:
8. Original doc
9. All .sig files
10. A README or signed manifest listing who signed what.

Pros: Standards-compliant, secure, and doesn’t rely on Microsoft or Adobe

Cons: No visual cues in the document itself; needs external tooling

Option 2: Convert to PDF and Use PGP-Capable Tools

1. Convert the Word document to PDF.
2. Use a tool like:
3. GnuPG with GPA or Kleopatra (Windows GUI for GnuPG)
4. Qubes + Split GPG (advanced setup)
5. Open-source apps like signify, OpenPGP.js, or GPGTools (macOS)

You can annotate the PDF with visual signature info, then sign the whole PDF file with your PGP key.

Team members then sign the same file, producing multiple .sig files. Again, these can be collected in a signed manifest or included in a ZIP bundle.

Option 3: Use git + git-crypt or signed commits

If your team uses Git:

1. Store the document (Word or PDF) in a Git repo.
2. Team members sign Git commits or tags with their PGP keys.
3. git commit -S -m "Signed by Alice"
4. You get PGP-signed change history, and it’s tamper-evident.

Pros: Clean, auditable, modern

Cons: Not visual inside the document, may require Git fluency

Option 4: PDF PGP-Signature Embedding via Custom Tools

1. Some workflows generate PDFs with visible fields saying “Digitally signed by Alice (PGP key ID)”.
2. You can:
3. Annotate the PDF with visible PGP signature blocks.
4. Use gpg --clearsign on a hash or summary of the PDF.

Recommended Hybrid Approach for Now

StepTool
1. Finalize document	MS Word / Export to PDF
2. Add visual signature placeholder (name, key ID, etc.)	Word/Adobe
3. Each person signs using gpg --detach-sign	GnuPG / PGP
4. Create a ZIP or folder with document + all .sig files	Shared location or repo
5. Optionally sign the ZIP itself	gpg --sign archive.zip