DigitalSignature.ProviderId

DigitalSignature.ProviderId property

Specifies the class ID of the signature provider. Default value is Empty (all zeroes) Guid.

public Guid ProviderId { get; set; }

Remarks

The cryptographic service provider (CSP) is an independent software module that actually performs cryptography algorithms for authentication, encoding, and encryption. Microsoft Office reserves the value of {00000000-0000-0000-0000-000000000000} for its default signature provider, and {000CD6A4-0000-0000-C000-000000000046} for its East Asian signature provider. The GUID of the additionally installed provider should be obtained from the documentation shipped with the provider.

Examples

using System;
using System.IO;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using Aspose.Cells;
using Aspose.Cells.DigitalSignatures;
using Aspose.Cells.Drawing;

namespace AsposeCellsExamples
{
    public class DigitalSignaturePropertyProviderIdDemo
    {
        public static void Run()
        {
            // Create self-signed certificate
            X509Certificate2 certificate;
            using (var rsa = RSA.Create())
            {
                var request = new CertificateRequest(
                    new X500DistinguishedName("cn=AsposeTest"),
                    rsa,
                    HashAlgorithmName.SHA256,
                    RSASignaturePadding.Pkcs1);
                
                certificate = request.CreateSelfSigned(DateTimeOffset.Now, DateTimeOffset.Now.AddHours(1));
            }

            // Create workbook and add signature line
            Workbook wb = new Workbook();
            Worksheet ws = wb.Worksheets[0];
            
            // Add dummy picture with signature line
            using (var ms = new MemoryStream())
            {
                ms.Write(new byte[] { 0x42, 0x4D, 0x1E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1A, 0x00, 0x00, 0x00 }, 0, 14);
                ms.Position = 0;
                
                int idx = ws.Pictures.Add(0, 0, ms);
                Picture pic = ws.Pictures[idx];
                pic.SignatureLine = new SignatureLine();
                pic.SignatureLine.ProviderId = Guid.NewGuid();
            }

            // Create digital signature
            var signature = new DigitalSignature(certificate, "Aspose ProviderId Demo", DateTime.Now);
            signature.ProviderId = ws.Pictures[0].SignatureLine.ProviderId;

            // Set digital signature and save
            DigitalSignatureCollection dsCollection = new DigitalSignatureCollection();
            dsCollection.Add(signature);
            wb.SetDigitalSignature(dsCollection);

            using (MemoryStream output = new MemoryStream())
            {
                wb.Save(output, SaveFormat.Xlsx);
            }
        }
    }
}

DigitalSignature.ProviderId