我使用itextsharp向PDF添加了数字签名，该签名正在完美添加。但是现在我需要在盒子中添加该数字签名。
我尝试了以下内容： - 1(在矩形中创建了一个文本形式字段，并试图用数字签名替换表单字段，但没有发生，因为它没有将其识别为签名字段。(IDK实际上是什么意思(
2(当我在Adobe中打开PDF时，我可以在签名悬停的矩形盒子上闪烁。无需验证。
，但我需要盒子中的签名。
我的代码添加了 @mkl答案的更改后：
PdfReader reader1 = new PdfReader(this.inputPDF);
PdfStamper st = PdfStamper.CreateSignature(reader1, new FileStream(this.outputPDF, FileMode.Create, FileAccess.ReadWrite), ' ');
AcroFields pdfFormFields = st.AcroFields;
st.SetEncryption(PdfWriter.STRENGTH40BITS, null, null, PdfWriter.AllowPrinting);
st.MoreInfo = this.metadata.getMetaData();
st.XmpMetadata = this.metadata.getStreamedMetaData();
PdfSignatureAppearance sap = st.SignatureAppearance;
sap.SignDate = Convert.ToDateTime(DateTime.Now.ToLocalTime());
sap.Layer2Font = new Font(Font.HELVETICA, 12, Font.BOLD);
sap.Layer2Text = "Digitally Signed nVICE PRESIDENT- nDate:" + ; //+ "nLocation: BENGALURU";
sap.SetCrypto(this.myCert.Akp, this.myCert.Chain, null, PdfSignatureAppearance.SELF_SIGNED);
sap.Contact = SigContact;
sap.Location = SigLocation;
Rectangle obj = new iTextSharp.text.Rectangle(75, 90, 600, 300);
sap.SetVisibleSignature(obj, 1, "sig");
sap.GetAppearance();
PdfTemplate layer20 = sap.GetLayer(2);
Rectangle rectangle = sap.Rect;
layer20.SetRGBColorStroke(0, 0, 0);
layer20.SetLineWidth(5);
layer20.Rectangle(00, 80, 250, 100);
layer20.Stroke();
st.close();
当前使用5.5.13。
此外，我在使用SSL证书上托管服务器时获得了一个误差长度超过4个字节。
相同的堆栈跟踪。
`System.IO.IOException was caught
HResult=-2146232800
Message=DER length more than 4 bytes: 32
Source=itextsharp
StackTrace:
at Org.BouncyCastle.Asn1.Asn1InputStream.ReadLength(Stream s, Int32 limit)
at Org.BouncyCastle.Asn1.Asn1InputStream.ReadObject()
at Org.BouncyCastle.Asn1.Asn1InputStream.BuildEncodableVector()
at Org.BouncyCastle.Asn1.Asn1InputStream.BuildDerEncodableVector(DefiniteLengthInputStream dIn)
at Org.BouncyCastle.Asn1.Asn1InputStream.CreateDerSequence(DefiniteLengthInputStream dIn)
at Org.BouncyCastle.Asn1.Asn1InputStream.BuildObject(Int32 tag, Int32 tagNo, Int32 length)
at Org.BouncyCastle.Asn1.Asn1InputStream.ReadObject()
at Org.BouncyCastle.Asn1.Asn1InputStream.BuildEncodableVector()
at Org.BouncyCastle.Asn1.Asn1InputStream.BuildDerEncodableVector(DefiniteLengthInputStream dIn)
at Org.BouncyCastle.Asn1.Asn1InputStream.CreateDerSequence(DefiniteLengthInputStream dIn)
at Org.BouncyCastle.Asn1.Asn1InputStream.BuildObject(Int32 tag, Int32 tagNo, Int32 length)
at Org.BouncyCastle.Asn1.Asn1InputStream.ReadObject()
at Org.BouncyCastle.Asn1.Asn1Object.FromStream(Stream inStr)
at Org.BouncyCastle.Pkcs.Pkcs12Store.Load(Stream input, Char[] password)
at Org.BouncyCastle.Pkcs.Pkcs12Store..ctor(Stream input, Char[] password)
at Letters.Models.PDFSigner.Sign(String SigReason, String SigContact, String SigLocation, Boolean visible, String strType, String path, String password) in :line 93`
编辑的代码再次共享，请帮助我查找是否有错误。
Stream path1 = new FileStream(path, FileMode.Open, FileAccess.Read);
Pkcs12Store pk12 = new Pkcs12Store(path1, password.ToCharArray());
path1.Dispose();
//then Iterate throught certificate entries to find the private key entry
string alias = null;
foreach (string tAlias in pk12.Aliases)
{
if (pk12.IsKeyEntry(tAlias))
{
alias = tAlias;
break;
}
}
var pk = pk12.GetKey(alias).Key;
PdfReader reader = new PdfReader(this.inputPDF);
FileStream os = new FileStream(this.outputPDF, FileMode.Create);
PdfStamper stamper = PdfStamper.CreateSignature(reader, os, ' ');
PdfSignatureAppearance appearance = stamper.SignatureAppearance;
appearance.Layer2Font = new Font(Font.FontFamily.HELVETICA, 12, Font.BOLD);`
使用itext 5.5.x签署PDF时，通常会做
之类的事情// Creating the reader and the stamper
PdfReader reader = new PdfReader(SRC);
FileStream os = new FileStream(DEST, FileMode.Create);
PdfStamper stamper = PdfStamper.CreateSignature(reader, os, ' ');
// Creating the appearance
PdfSignatureAppearance appearance = stamper.SignatureAppearance;
appearance.Reason = "Test customized appearance";
appearance.Location = "Singularity";
appearance.SetVisibleSignature(new Rectangle(36, 748, 144, 780), 1, "sig");
// Creating the signature
IExternalSignature pks = new PrivateKeySignature(parameters, DigestAlgorithms.SHA256);
MakeSignature.SignDetached(appearance, pks, chain, null, null, null, 0, CryptoStandard.CADES);
您可以通过在appearance.SetVisibleSignature调用后在图层模板上工作，例如这样：
// trigger creation of default layers contents
appearance.GetAppearance();
// Customize the layer contents
PdfTemplate layer2 = appearance.GetLayer(2);
Rectangle rect = appearance.Rect;
layer2.SetRGBColorStroke(255, 0, 0);
layer2.SetLineWidth(2);
layer2.Rectangle(rect.Left, rect.Bottom, rect.Width, rect.Height);
layer2.Stroke();
沿签名外观边框绘制红线