Error during signature verification. Signature contains incorrect, unrecognized, corrupted or suspicious data. Support Information: SigDict /Contents illegal data

But, when I open the PDF in Acrobat Reader, I see a bunch of validation failures.. Attaching the sample pdf for reference.

Which bunch of validation failures? I only see one:

Looking into it, though, a number of issues become obvious:

• There is no signature container embedded in the signature field value, instead the placeholder is filled with 0x00 bytes. This explains the message by Acrobat, a sequence of 0x00 bytes is not a valid signature container.
• The gap in the ByteRange array starts at offset 482900. but the actual signature placeholder starts at offset 11036. This is not just off-by-1 or so, it's completely different.
• The second range in the ByteRange array ends at offset 511033 but tghe file size is just 509215.

The first item indicates that the PDF has only been prepared for signing but no signature container has actually been embedded. The latter items indicate that after preparing for signing the PDF has again been opened and then saved regularly and not as a new revision by appending an incremental update.

The PDFBox example signing code does neither of these errors. Thus, please have a look at the PDFBox examples and do as they do.

I'm having a similar problem, trying to do multiple signatures in my test environment. What could be the issue and possible fix?

@Benjamín36680953jfh8,

In your example file the initial revision (containing the first signature) has been re-saved after signing (not applying changes in an incremental update but completely re-writing the PDF). This not only changed the signed byte range contents but also moved the signature dictionary (rendering the ByteRange entry itself incorrect) and changed the size of the single-revision PDF (making the ByteRange not covering a whole revision anymore). Furthermore, the software doing this re-write has an error in its cross reference table writing code.

Thus, the first signature in your document must be reported as broken.

After that first revision with the broken first signature there are a number of additional revisions (saved using incremental updates) to apply a second signature:

• (Update 1) Adding an empty signature field
• (Update 2) Adding an appearance to the new empty signature field
• (Update 3) Signing the new signature field

At first glance these steps look ok.

So you should check which code in your setup broke the initial PDF and fix that.

There are some errors in your signed PDF:

• The ByteRange entry is incorrect. For signatures in general the signed byte ranges should be exactly the whole signed revision except the value of the signature Contents key, and for PAdES signatures they must be - and Adobe Acrobat only accepts signatures with byte ranges of that kind. Your signed ranges are a bit off, though:
  

  ...

  

  The Contents value starts at 0x3521 = 13601 but according to your ByteRange value it should start at 13589. Similarly it ends at 0x40db = 16603 but it should end at 16591.

• Your signed attributes are not properly DER encoded:
  

  The algorithm SHA256 is the DEFAULT value of the signingCertificateV2 attribute. Thus, it must be left out of the DER encoding.

(There might be more issues but these two lept to the eye.)

Adobe Acrobat is very sensitive in regard to the ByteRange value but probably not in regard to the DER encoding. Other validators, though, may also insist on proper DER encoding.

@Lana2287583331qf 

Hello, is there any sloution? My file freezes so much 😞

As @Keshav_pki, @Ravinder5FC4, and @Red5E0F could not share example documents, there was no solution for them.

In @rossi.nicolas' case his file simply was completely broken (and apparently broken by a signing software that worked incorrectly), so the solution there was to sign using an application that does sign correctly.

As long as you don't share an example PDF that's representative for your issue, you're unlikely to find any analysis let alone solution here.

Can you name a public website that verifies the signature OK, so we can try it and compare?

@Keshav_pki @Ravinder5FC4 @8768829 @vladan saveljic @Bernd Alheit @YatharthS 

Does anyone help me with this issue. If there is a solution already?

I have a signed PDF document along with Time-stamp and DSS. But when opened in Adobe reader, Signature is not valid and have the following error:

Signature contains incorrect, unrecognized, corrupted or suspicious data. Support Information: SigDict /Contents illegal data

I verified the Signature Field /Annot dictionary it seems normal. /Annot references a Signature dictionary via its /V field. And the Signature dictionary has /Type /Sig which constains all the mandatory fields.