Sonnt,
Sonnt wrote:
> As you say in another topic("Hash computation problem"), the signing
> session must be kept during deferred signing.
> Is there any way to avoid doing this?
As some properties of the signing session (date-time of document
manipulation and of signing, generated ID, ...) are included in the stamped
PDF, you have to keep the signing session. But there are different ways to
do that:
* the easy way: Use the same PdfStamper throughout that session;
* the challenging way: Patch iText to enable it to use the same signing
session properties while at the same time keeping the information unique
enough;
* the compromise: After preparing the PDF for integrated signing and
calculating the digest, keep this intermediate PDF (in case of append mode,
keeping the part containing the data of the new revision suffices) and later
(as soon as you have the signature) insert that signature manually.
Sonnt wrote:
> I tried like that:
> 1. create digest: i create a file with a signature (not the signature of
> user) and a digest
> 2. sign digest: user signature
> 3. insert signature: replace the signature in phase 1 with the signature
> in phase 2. But it seems to go wrong!
This sounds like an implementation of the compromise mentioned above. The
concept in general works, so most likely there is a problem in your very
implementation thereof.
In some threads on topics like this, Andreas has referenced a sample
implementation of that compromise; maybe you should have a look at that
sample.
Regards, Michael.
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