Digital signatures: document has been altered when bEnableCryptoComplyLibrary is set to 1

[davidurt]

Hi,

we are currently signing PDF documents with ECDSA signatures through custom sofware (= that makes use of iText). When I open a signed document on a 'consumer' version of Adobe Reader all signatures are valid. When I open the same document on an 'enterprise' version of Adobe Reader the signature is invalid (= the document has been altered). Documents signed with RSA do not have issues.

We finally found the registry setting that is causing this: HKEY_CURRENT_USER\SOFTWARE\Adobe\Acrobat Reader\DC\Security\bEnableCryptoComplyLibrary. When it is set to 0 on an 'enterprise' system, there there is no issue.

I did a search on that bEnableCryptoComplyLibrary setting but was not able to find any information about it. Can anyone help me with this? What is the implication of disabling/enabling it?

Thank you

[absethi]

Hi @davidurt ,

Apologies for the inconvienece.

CryptoComply is the new library support added in Adobe Acrobat/Reader.

More details can be found here :- https://helpx.adobe.com/in/acrobat/using/whats-new/2021-june.html

Can you please share the affected files with us so that we can replicate the issue on our end.

Reagrds,

Abhinav Sethi

[davidurt]

Hi @absethi, 

Thank you for your response.

You can find enclosed a document that has been signed three times:

• Rev. 1: signed by me, making using of iText, with an 'old' Belgian eID card that uses SHA1withRSA.
• Rev. 2: signed by a colleague, also making using of iText, with a new Belgian eID card that uses SHA384withECDSA
• Rev. 3: signed by the same colleague, this time with Adobe Acrobat Reader, with the same (new) Belgian eID card.

So, when we disable the 'SafeLogic CryptoComply' feature, all signatures are valid.

When we enable the 'SafeLogic CryptoComply' feature, signature Rev. 2 is invalid. Rev. 1 and Rev. 3 are valid.

Regards, David

[absethi]

Thanks @davidurt for sharing the file.

We have logged a bug for it and are working on it.

Regards

Abhinav Sethi

[Gwen28422330xlop]

Is there already a solution for the bug because we are experiencing the same problem.