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V22.1
.NET Framework 4.5.2+

DocumentSigner.Sign(Stream, Stream, SignatureOptions, SignatureInfo) Method

Signs a file with the specified signature and signature options.

Namespace: DevExpress.Office.DigitalSignatures

Assembly: DevExpress.Docs.v22.1.dll

Declaration

public void Sign(
    Stream inputStream,
    Stream outputStream,
    SignatureOptions options,
    SignatureInfo signatureInfo
)

Parameters

Name Type Description
inputStream Stream

The stream that contains a file to sign.

outputStream Stream

The stream to which to save the file.

options SignatureOptions

An object that contains signature options.

signatureInfo SignatureInfo

An object that contains the signature information.

Remarks

Use the Sign method to sign documents and save the result. You can use XAdES-BES and XAdES-T signatures with X.509 certificates. Office File API supports signatures in the following document formats:

  • Microsoft Word
    • Open XML (DOCX, DOTX, DOTM, DOCM)
    • 97-2003 (DOC, DOT)
  • Microsoft Excel
    • Open XML (XLSX, XLTX, XLSM)
    • 97-2003 binary file (XLS, XLT)
  • Microsoft PowerPoint
    • PPTX, PPT

The SignatureOptions class object allows you to specify validation data (certificate, hash algorithm, timestamp, etc.). Pass the SignatureInfo object to define the signer information.

The options and signatureInfo parameters cannot be null.

The code sample below signs and saves a Word and Excel document:

using DevExpress.Office.DigitalSignatures;
using System;
using System.Diagnostics;
using System.Security.Cryptography.X509Certificates;

static void Main(string[] args)
{
    //Sign a workbook:
    using (Stream stream = new FileStream("Template.xlsx", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        using (Stream outputStream = new FileStream("Workbook_signed.xlsx", FileMode.Create, FileAccess.Write, FileShare.Read))
        {
            SignDocument(stream, outputStream);
        }
    }

    //Sign a document:
    using (Stream stream = new FileStream("Template.docx", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        using (Stream outputStream = new FileStream("Template_signed.docx", FileMode.Create, FileAccess.Write, FileShare.Read))
        {
            SignDocument(stream, outputStream);
        }
    }
}
static void SignDocument(Stream path, Stream output)
{
    DocumentSigner documentSigner = new DocumentSigner();
    documentSigner.Sign(path, output,
     CreateSignatureOptions(), CreateSignatureInfo());
}

//Specify a signature certificate and digest method:
static SignatureOptions CreateSignatureOptions()
{
    X509Certificate2 certificate = new X509Certificate2("Certificate/SignDemo.pfx", "dxdemo");
    Uri tsaServer = new Uri("https://freetsa.org/tsr");
    SignatureOptions options = new SignatureOptions();
    options.Certificate = certificate;
    if (tsaServer != null)
        options.TsaClient = new TsaClient(tsaServer, HashAlgorithmType.SHA256);

    //In this example, certificate validation is skipped
    options.SignatureFlags &= ~SignatureFlags.ValidateCertificate;
    options.CertificateKeyUsageFlags = X509KeyUsageFlags.None;
    options.DigestMethod = HashAlgorithmType.SHA256;

    X509ChainPolicy policy = new X509ChainPolicy();
    policy.RevocationMode = X509RevocationMode.NoCheck;
    policy.RevocationFlag = X509RevocationFlag.ExcludeRoot;
    policy.VerificationFlags |= X509VerificationFlags.AllowUnknownCertificateAuthority |
        X509VerificationFlags.IgnoreCertificateAuthorityRevocationUnknown;
    options.CertificatePolicy = policy;
    options.TimestampCertificatePolicy = policy;
    return options;
}

//Specify signer information:
static SignatureInfo CreateSignatureInfo()
{
    SignatureInfo signatureInfo = new SignatureInfo();
    signatureInfo.CommitmentType = CommitmentType.ProofOfApproval;
    signatureInfo.Time = DateTime.UtcNow;
    signatureInfo.ClaimedRoles.Clear();
    signatureInfo.ClaimedRoles.Add("Sales Representative");
    signatureInfo.Comments = "Demo Digital Signature";

    return signatureInfo;
}
See Also