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RSAPKCS1SignatureFormatter Class
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RSAPKCS1SignatureFormatter Class

Creates an RSA PKCS #1 version 1.5 signature.


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

public class RSAPKCS1SignatureFormatter : AsymmetricSignatureFormatter

The RSAPKCS1SignatureFormatter type exposes the following members.

Public methodRSAPKCS1SignatureFormatter()Initializes a new instance of the RSAPKCS1SignatureFormatter class.
Public methodRSAPKCS1SignatureFormatter(AsymmetricAlgorithm)Initializes a new instance of the RSAPKCS1SignatureFormatter class with the specified key.

Public methodCreateSignature(Byte[])Creates the RSA PKCS #1 signature for the specified data. (Overrides AsymmetricSignatureFormatter.CreateSignature(Byte[]).)
Public methodCreateSignature(HashAlgorithm)Creates the signature from the specified hash value. (Inherited from AsymmetricSignatureFormatter.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSetHashAlgorithmSets the hash algorithm to use for creating the signature. (Overrides AsymmetricSignatureFormatter.SetHashAlgorithm(String).)
Public methodSetKeySets the private key to use for creating the signature. (Overrides AsymmetricSignatureFormatter.SetKey(AsymmetricAlgorithm).)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

This class is used to create a digital signature using the RSA algorithm.

Use RSAPKCS1SignatureDeformatter to verify digital signatures with the RSA algorithm.

The following example demonstrates how to create a PKCS #1 version 1.5 signature.

using System;
using System.Security.Cryptography;

class RSASample

    static void Main()
            //Create a new instance of RSACryptoServiceProvider. 
            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
                //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  
                //RSACryptoServiceProvider to transfer the key information.
                RSAPKCS1SignatureFormatter RSAFormatter = new RSAPKCS1SignatureFormatter(rsa);

                //Set the hash algorithm to SHA256.

                //Create a signature for HashValue and return it. 
                byte[] SignedHash = RSAFormatter.CreateSignature(hash);

        catch (CryptographicException e)


.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
© 2015 Microsoft