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certified pdf

Hello i've a question. Is it possible to edit a certified pdf without losing the certification (Signature). ?
No idea how well either of these will work but you can try the following

Use a specialized PDF editing software that supports adding or modifying form fields. This allows you to modify the PDF's content without invalidating the digital signature. Here are the steps:
Open the signed PDF in the editing software
Add the new form fields or modify the existing ones
Save the PDF with a new name to avoid overwriting the original file
The digital signature remains valid, and the document can be verified using the same digital signature.
Another method is to use a tool to remove the digital signature, make the necessary changes to the PDF, and then re-apply the signature. Here are the steps:
Use a tool to remove the digital signature from the PDF file
Make the necessary changes to the PDF
Apply the digital signature to the modified PDF using a digital signature tool. Make sure to use the same certificate used to sign the original document to apply the new digital signature.
Save the PDF with a new name to avoid overwriting the original file
Thank you for your response. But i am looking for a way to copy de signature, i dont have the siganture password or anything. My english is very bad so i hope you understand me.
(Apr 7, 2023 04:07 PM)klaas123 Wrote:  Thank you for your response. But i am looking for a way to copy de signature, i dont have the siganture password or anything. My english is very bad so i hope you understand me.

Need to start by searching for a way to extract the digital signature so it can be reapplied back after editing, but I got honestly have no idea how one would go about that
It's not possible to edit a certified PDF without ruining the certification, since any modifications will mess with the digital signature. But some PDF editing tools might let you make minor changes using "incremental updates" without invalidating the certification.
thank you guys, very helpful information. Isn't it possible do duplicate or copy the signature?
(Apr 7, 2023 07:33 PM)klaas123 Wrote:  thank you guys, very helpful information. Isn't it possible do duplicate or copy the signature?

Best I can figure it to attempt to extract it to re-apply it after the modifications as noted above, but Ive never even thought of attempting something like that, so your kinda on your own here.
(Apr 7, 2023 07:33 PM)klaas123 Wrote:  thank you guys, very helpful information. Isn't it possible do duplicate or copy the signature?

Signatures and their signing keys are used to ensure the authenticity and non-repudiation of the file and verify that no changes are made. The process is designed so that any changes will cause the verification to fail. You will need the original signing key and certificate. These are used to encrypt/sign the file and so are not embedded within.
(Apr 8, 2023 12:44 PM)DramaKing Wrote:  Signatures and their signing keys are used to ensure the authenticity and non-repudiation of the file and verify that no changes are made. The process is designed so that any changes will cause the verification to fail. You will need the original signing key and certificate. These are used to encrypt/sign the file and so are not embedded within.

I understand this, but i tought that this is a hackers forum so maybe there was a way to 'hack' it 😆
(Apr 7, 2023 06:22 PM)Pikachuu Wrote:  It's not possible to edit a certified PDF without ruining the certification, since any modifications will mess with the digital signature. But some PDF editing tools might let you make minor changes using "incremental updates" without invalidating the certification.

Pretty much this I guess.
(Apr 8, 2023 03:12 PM)klaas123 Wrote:  I understand this, but i tought that this is a hackers forum so maybe there was a way to 'hack' it 😆

I think you are missing the point of the aignature here...
(Apr 8, 2023 03:12 PM)klaas123 Wrote:  I understand this, but i tought that this is a hackers forum so maybe there was a way to 'hack' it 😆

I didn't say that there wasn't a way. I checked Adobe's documentation, and here's how you would do it.

  1. Decrypt hash using public key.
  2. Make changes in such a way that you get a hash collision (shouldn't be strictly necessary).
  3. Obtain private key (which was done by a group of hackers for Samsung apps) or crack key. I can't find the key type and length, but I'll assume that it's the same as the SSH default 2048-bit RSA. Wouldn't take you more than 300 trillion years according to Bing AI.
  4. Resign document with private key.
(Apr 9, 2023 05:48 AM)DramaKing Wrote:  Wouldn't take you more than 300 trillion years according to Bing AI.

🤣 Yea, that sounds about right...


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