RSAPKCS1SignatureDeformatter Class

Definition

Namespace:

System.Security.Cryptography

Assembly:

System.Security.Cryptography.dll

Source:

RSAPKCS1SignatureDeformatter.cs

Verifies an RSA PKCS #1 version 1.5 signature.

public ref class RSAPKCS1SignatureDeformatter : System::Security::Cryptography::AsymmetricSignatureDeformatter

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public class RSAPKCS1SignatureDeformatter : System.Security.Cryptography.AsymmetricSignatureDeformatter

[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
type RSAPKCS1SignatureDeformatter = class
    inherit AsymmetricSignatureDeformatter

Public Class RSAPKCS1SignatureDeformatter
Inherits AsymmetricSignatureDeformatter

Inheritance

Object

AsymmetricSignatureDeformatter

RSAPKCS1SignatureDeformatter

Attributes

UnsupportedOSPlatformAttribute

Examples

The following example demonstrates how to use the VerifySignature method to verify a signature.

using System;
using System.Security.Cryptography;

class RSASample
{

    static void Main()
    {
        try
        {
            //Create a new instance of RSA.
            using (RSA rsa = RSA.Create())
            {
                //The hash to sign.
                byte[] hash;
                using (SHA256 sha256 = SHA256.Create())
                {
                    byte[] data = new byte[] { 59, 4, 248, 102, 77, 97, 142, 201, 210, 12, 224, 93, 25, 41, 100, 197, 213, 134, 130, 135 };
                    hash = sha256.ComputeHash(data);
                }

                //Create an RSASignatureFormatter object and pass it the 
                //RSA instance to transfer the key information.
                RSAPKCS1SignatureFormatter RSAFormatter = new RSAPKCS1SignatureFormatter(rsa);

                //Set the hash algorithm to SHA256.
                RSAFormatter.SetHashAlgorithm("SHA256");

                //Create a signature for HashValue and return it.
                byte[] signedHash = RSAFormatter.CreateSignature(hash);
                //Create an RSAPKCS1SignatureDeformatter object and pass it the  
                //RSA instance to transfer the key information.
                RSAPKCS1SignatureDeformatter RSADeformatter = new RSAPKCS1SignatureDeformatter(rsa);
                RSADeformatter.SetHashAlgorithm("SHA256");
                //Verify the hash and display the results to the console. 
                if (RSADeformatter.VerifySignature(hash, signedHash))
                {
                    Console.WriteLine("The signature was verified.");
                }
                else
                {
                    Console.WriteLine("The signature was not verified.");
                }
            }
        }
        catch (CryptographicException e)
        {
            Console.WriteLine(e.Message);
        }
    }
}

Imports System.Security.Cryptography

Friend Class RSASample

    Shared Sub Main()
        Try
            'Create a new instance of RSA.
            Using rsa As RSA = RSA.Create()
                'The hash to sign.
                Dim hash() As Byte
                Using sha256 As SHA256 = SHA256.Create()
                    Dim data() As Byte = { 59, 4, 248, 102, 77, 97, 142, 201, 210, 12, 224, 93, 25, 41, 100, 197, 213, 134, 130, 135 }
                    hash = sha256.ComputeHash(data)
                End Using

                'Create an RSASignatureFormatter object and pass it the 
                'RSA instance to transfer the key information.
                Dim RSAFormatter As New RSAPKCS1SignatureFormatter(rsa)

                'Set the hash algorithm to SHA256.
                RSAFormatter.SetHashAlgorithm("SHA256")

                'Create a signature for HashValue and return it.
                Dim signedHash() As Byte = RSAFormatter.CreateSignature(hash)
                'Create an RSAPKCS1SignatureDeformatter object and pass it the  
                'RSA instance to transfer the key information.
                Dim RSADeformatter As New RSAPKCS1SignatureDeformatter(rsa)
                RSADeformatter.SetHashAlgorithm("SHA256")
                'Verify the hash and display the results to the console. 
                If RSADeformatter.VerifySignature(hash, signedHash) Then
                    Console.WriteLine("The signature was verified.")
                Else
                    Console.WriteLine("The signature was not verified.")
                End If
            End Using

        Catch e As CryptographicException
            Console.WriteLine(e.Message)
        End Try
    End Sub

End Class

Remarks

This class is used to verify a digital signature made with the RSA algorithm.

Use RSAPKCS1SignatureFormatter to create digital signatures with the RSA algorithm.

Constructors

RSAPKCS1SignatureDeformatter()	Initializes a new instance of the RSAPKCS1SignatureDeformatter class.
RSAPKCS1SignatureDeformatter(AsymmetricAlgorithm)	Initializes a new instance of the RSAPKCS1SignatureDeformatter class with the specified key.

Methods

Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
SetHashAlgorithm(String)	Sets the hash algorithm to use for verifying the signature.
SetKey(AsymmetricAlgorithm)	Sets the public key to use for verifying the signature.
ToString()	Returns a string that represents the current object. (Inherited from Object)
VerifySignature(Byte[], Byte[])	Verifies the RSA PKCS#1 signature for the specified data.
VerifySignature(HashAlgorithm, Byte[])	Verifies the signature from the specified hash value. (Inherited from AsymmetricSignatureDeformatter)

See also

• Cryptographic Services