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SignatureDescription Class

Contains information about the properties of a digital signature.

Namespace:  System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)

[ComVisibleAttribute(true)]
public class SignatureDescription

The following code example demonstrates how to use members of the SignatureDescription class.

using System;
using System.Security;
using System.Security.Cryptography;

class SignatureDescriptionImpl
{
    [STAThread]
    static void Main(string[] args)
    {
        // Create a digital signature based on RSA encryption.
        SignatureDescription rsaSignature = CreateRSAPKCS1Signature();
        ShowProperties(rsaSignature);

        // Create a digital signature based on DSA encryption.
        SignatureDescription dsaSignature = CreateDSASignature();
        ShowProperties(dsaSignature);

        // Create a HashAlgorithm using the digest algorithm of the signature.
        HashAlgorithm hashAlgorithm = dsaSignature.CreateDigest();
        Console.WriteLine("\nHash algorithm for the DigestAlgorithm property:"
            + " " + hashAlgorithm.ToString());

        // Create an AsymmetricSignatureFormatter instance using the DSA key.
        DSA dsa = DSA.Create();
        AsymmetricSignatureFormatter asymmetricFormatter =
            CreateDSAFormatter(dsa);

        // Create an AsymmetricSignatureDeformatter instance using the 
        // DSA key.
        AsymmetricSignatureDeformatter asymmetricDeformatter =
            CreateDSADeformatter(dsa);

        Console.WriteLine("This sample completed successfully; " +
            "press Enter to exit.");
        Console.ReadLine();
    }

    // Create a SignatureDescription for RSA encryption. 
    private static SignatureDescription CreateRSAPKCS1Signature()
    {
        SignatureDescription signatureDescription = 
            new SignatureDescription();

        // Set the key algorithm property for RSA encryption.
        signatureDescription.KeyAlgorithm =
            "System.Security.Cryptography.RSACryptoServiceProvider";

        // Set the digest algorithm for RSA encryption using the 
        // SHA1 provider.
        signatureDescription.DigestAlgorithm =
            "System.Security.Cryptography.SHA1CryptoServiceProvider";

        // Set the formatter algorithm with the RSAPKCS1 formatter.
        signatureDescription.FormatterAlgorithm =
            "System.Security.Cryptography.RSAPKCS1SignatureFormatter";

        // Set the formatter algorithm with the RSAPKCS1 deformatter.
        signatureDescription.DeformatterAlgorithm =
            "System.Security.Cryptography.RSAPKCS1SignatureDeformatter";

        return signatureDescription;
    }

    // Create a SignatureDescription using a constructed SecurityElement for  
    // DSA encryption. 
    private static SignatureDescription CreateDSASignature()
    {
        SecurityElement securityElement = new SecurityElement("DSASignature");

        // Create new security elements for the four algorithms.
        securityElement.AddChild(new SecurityElement(
            "Key",
            "System.Security.Cryptography.DSACryptoServiceProvider"));
        securityElement.AddChild(new SecurityElement(
            "Digest",
            "System.Security.Cryptography.SHA1CryptoServiceProvider")); 
        securityElement.AddChild(new SecurityElement(
            "Formatter",
            "System.Security.Cryptography.DSASignatureFormatter"));
        securityElement.AddChild(new SecurityElement(
            "Deformatter",
            "System.Security.Cryptography.DSASignatureDeformatter"));

        SignatureDescription signatureDescription = 
            new SignatureDescription(securityElement);

        return signatureDescription;
    }

    // Create a signature formatter for DSA encryption. 
    private static AsymmetricSignatureFormatter CreateDSAFormatter(DSA dsa)
    {
        // Create a DSA signature formatter for encryption.
        SignatureDescription signatureDescription = 
            new SignatureDescription();
        signatureDescription.FormatterAlgorithm =
            "System.Security.Cryptography.DSASignatureFormatter";

        AsymmetricSignatureFormatter asymmetricFormatter =
            signatureDescription.CreateFormatter(dsa);

        Console.WriteLine("\nCreated formatter : " + 
            asymmetricFormatter.ToString());
        return asymmetricFormatter;
    }

    // Create a signature deformatter for DSA decryption. 
    private static AsymmetricSignatureDeformatter CreateDSADeformatter(
        DSA dsa)
    {
        // Create a DSA signature deformatter to verify the signature.
        SignatureDescription signatureDescription = 
            new SignatureDescription();
        signatureDescription.DeformatterAlgorithm =
            "System.Security.Cryptography.DSASignatureDeformatter";

        AsymmetricSignatureDeformatter asymmetricDeformatter =
            signatureDescription.CreateDeformatter(dsa);

        Console.WriteLine("\nCreated deformatter : " + 
            asymmetricDeformatter.ToString());
        return asymmetricDeformatter;
    }

    // Display to the console the properties of the specified 
    // SignatureDescription. 
    private static void ShowProperties(
        SignatureDescription signatureDescription)
    {
        // Retrieve the class path for the specified SignatureDescription.
        string classDescription = signatureDescription.ToString();

        string deformatterAlgorithm = 
            signatureDescription.DeformatterAlgorithm;
        string formatterAlgorithm = signatureDescription.FormatterAlgorithm;
        string digestAlgorithm = signatureDescription.DigestAlgorithm;
        string keyAlgorithm = signatureDescription.KeyAlgorithm;

        Console.WriteLine("\n** " + classDescription + " **");
        Console.WriteLine("DeformatterAlgorithm : " + deformatterAlgorithm);
        Console.WriteLine("FormatterAlgorithm : " + formatterAlgorithm);
        Console.WriteLine("DigestAlgorithm : " + digestAlgorithm);
        Console.WriteLine("KeyAlgorithm : " + keyAlgorithm);
    }
}
// 
// This sample produces the following output: 
//  
// ** System.Security.Cryptography.SignatureDescription ** 
// DeformatterAlgorithm : System.Security.Cryptography. 
// RSAPKCS1SignatureDeformatter 
//  
// FormatterAlgorithm : System.Security.Cryptography. 
// RSAPKCS1SignatureFormatter 
// DigestAlgorithm : System.Security.Cryptography.SHA1CryptoServiceProvider 
// KeyAlgorithm : System.Security.Cryptography.RSACryptoServiceProvider 
//  
// ** System.Security.Cryptography.SignatureDescription ** 
// DeformatterAlgorithm : System.Security.Cryptography.DSASignatureDeformatter 
// FormatterAlgorithm : System.Security.Cryptography.DSASignatureFormatter 
// DigestAlgorithm : System.Security.Cryptography.SHA1CryptoServiceProvider 
// KeyAlgorithm : System.Security.Cryptography.DSACryptoServiceProvider 
//  
// Hash algorithm for the DigestAlgorithm property:  
// System.Security.Cryptography.SH 
// A1CryptoServiceProvider 
//  
// Created formatter : System.Security.Cryptography.DSASignatureFormatter 
//  
// Created deformatter : System.Security.Cryptography.DSASignatureDeformatter 
// This sample completed successfully; press Enter to exit.

System.Object
  System.Security.Cryptography.SignatureDescription

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0

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