签名在iTextSharp中无效 [英] A signature is not valid in iTextSharp

问题描述

您好，

我有一个VB.NET脚本，可以签署PDF文档。这意味着 - 插入签名和时间戳。但最终文件未经过验证，并显示签名无效：此文件已被更改或损坏



以下是代码：

Hello,
I got a VB.NET script which makes a PDF document signed. It means - insert a signature and a timestamp. But the final document is not verified and it shows that the signature is not valid: "this document has been altered or corrupted"

Here is the code:

certificateData = podepsat(8)
Dim bytes as Byte()
If String.IsNullOrEmpty(podepsat(2)) Then
   bytes = certificateData.Export(X509ContentType.Pfx)
Else
   bytes = certificateData.Export(X509ContentType.Pfx, podepsat(2))
End If

                processCert(bytes, podepsat(2))

                Dim tsc As ITSAClient = New TSAClientBouncyCastle(podepsat(9), podepsat(10), podepsat(11))

                Dim reader As New PdfReader(fileName)
                fileName = "signed-" & fileName
                Dim fout As New FileStream(fileName, FileMode.Create, FileAccess.Write)
                Dim stp As PdfStamper = PdfStamper.CreateSignature(reader, fout, "\0", Nothing, False)
                Dim sap As PdfSignatureAppearance = stp.SignatureAppearance

                sap.SetCrypto(Nothing, chain, Nothing, PdfSignatureAppearance.SELF_SIGNED)
                sap.Reason = podepsat(3)
                sap.Contact = podepsat(4)
                sap.Location = podepsat(5)
                sap.SignDate = podepsat(6)
                sap.SetVisibleSignature(New iTextSharp.text.Rectangle(100, 100, 300, 200), 1, "Signature")
                Dim dic As New PdfSignature(PdfName.ADOBE_PPKLITE, New PdfName("adbe.pkcs7.detached"))
                dic.Reason = sap.Reason
                dic.Location = sap.Location
                dic.Contact = sap.Contact
                dic.Date = New PdfDate(sap.SignDate)
                sap.CryptoDictionary = dic

                Dim contentEstimated As Integer = 15000
                Dim exc As New Dictionary(Of PdfName, Integer)
                exc(PdfName.CONTENTS) = contentEstimated * 2 + 2
                sap.PreClose(exc)

                Dim sgn As New PdfPKCS7(akp, chain, Nothing, "SHA1", False)
                Dim messageDigest As IDigest = DigestUtilities.GetDigest("SHA1")
                Dim data As Stream = sap.GetRangeStream()
                Dim buf As Byte() = New Byte(8191) {}
                Dim n As Integer
                While (n = data.Read(buf, 0, buf.Length)) > 0
                    messageDigest.BlockUpdate(buf, 0, n)
                End While
                Dim hash As Byte() = New Byte(messageDigest.GetDigestSize() - 1) {}
                messageDigest.DoFinal(hash, 0)
                Dim cal As DateTime = DateTime.Now
                Dim ocsp As Byte() = Nothing
                If chain.Length >= 2 Then
                    Dim url As [String] = PdfPKCS7.GetOCSPURL(chain(0))
                    If url IsNot Nothing AndAlso url.Length > 0 Then
                        ocsp = New OcspClientBouncyCastle().GetEncoded(chain(0), chain(1), url)
                    End If
                End If
                Dim sh As Byte() = sgn.GetAuthenticatedAttributeBytes(hash, cal, ocsp)
                sgn.Update(sh, 0, sh.Length)

                Dim encodedSig As Byte() = sgn.GetEncodedPKCS7(hash, cal, tsc, ocsp)
                If contentEstimated + 2 < encodedSig.Length Then
                    Throw New Exception("Not enough space")
                End If

                Dim paddedSig As Byte() = New Byte(contentEstimated - 1) {}
                System.Array.Copy(encodedSig, 0, paddedSig, 0, encodedSig.Length)

                Dim dic2 As New PdfDictionary()
                dic2.Put(PdfName.CONTENTS, New PdfString(paddedSig).SetHexWriting(True))

                sap.Close(dic2)

你能帮我吗，问题出在哪里？

processCert填写akp和代码中定义的链。

certificateData也被声明了。



我找不到问题..帮助请解决。



感谢您的帮助！

Can you help me, please, where is the problem?
processCert fill the akp and chain which are defined up in the code.
certificateData is also declared up.

I can`t find the problem.. Help me solve it, please.

Thank you for your help!

推荐答案

签名者根证书安装在Windows？

Pdf查看器是否信任Windows证书存储区？假设Acrobat，请参阅此文章： http://blogs.adobe.com/security/2008/08/setting_signature_trust_in_ado_2 .html [ ^ ] （这里描述的设置仍然有效）

Is the signer root certificate installed in windows?
Is the Windows Certificate store trusted by the Pdf viewer? Supposing Acrobat, see this article: http://blogs.adobe.com/security/2008/08/setting_signature_trust_in_ado_2.html[^] (the settings described there are still valid)

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