RSAPKCS1SignatureDeformatter.VerifySignature(Byte[], Byte[]) Method

Definition

Namespace:

System.Security.Cryptography

Assemblies:

netstandard.dll, System.Security.Cryptography.dll

Source:

RSAPKCS1SignatureDeformatter.cs

Verifies the RSA PKCS#1 signature for the specified data.

C#

public override bool VerifySignature(byte[] rgbHash, byte[] rgbSignature);

Parameters

rgbHash

Byte[]

The data signed with rgbSignature.

rgbSignature

Byte[]

The signature to be verified for rgbHash.

Returns

Boolean

true if rgbSignature matches the signature computed using the specified hash algorithm and key on rgbHash; otherwise, false.

Exceptions

CryptographicUnexpectedOperationException

The key is null.

-or-

The hash algorithm is null.

ArgumentNullException

The rgbHash parameter is null.

-or-

The rgbSignature parameter is null.

Examples

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

C#

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);
        }
    }
}

Remarks

You must specify a key and a hash algorithm before calling this method.

Applies to

See also

• Cryptographic Services