AsymmetricKeyExchangeDeformatter 类

定义

public ref class AsymmetricKeyExchangeDeformatter abstract

public abstract class AsymmetricKeyExchangeDeformatter

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public abstract class AsymmetricKeyExchangeDeformatter

[System.Runtime.InteropServices.ComVisible(true)]
public abstract class AsymmetricKeyExchangeDeformatter

type AsymmetricKeyExchangeDeformatter = class

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

[<System.Runtime.InteropServices.ComVisible(true)>]
type AsymmetricKeyExchangeDeformatter = class

Public MustInherit Class AsymmetricKeyExchangeDeformatter

继承

Object

AsymmetricKeyExchangeDeformatter

派生

System.Security.Cryptography.RSAOAEPKeyExchangeDeformatter

System.Security.Cryptography.RSAPKCS1KeyExchangeDeformatter

属性

UnsupportedOSPlatformAttribute ComVisibleAttribute

示例

以下示例演示如何扩展 AsymmetricKeyExchangeDeformatter 类。

using System;
using System.Security.Cryptography;

namespace Contoso
{
    public class ContosoDeformatter : AsymmetricKeyExchangeDeformatter
    {
        private RSA _rsaKey;

        // Default constructor.
        public ContosoDeformatter() { }

        // Constructor with the public key to use for encryption.
        public ContosoDeformatter(AsymmetricAlgorithm key)
        {
            SetKey(key);
        }

        // Set the public key for encyption operations.
        public override void SetKey(AsymmetricAlgorithm key)
        {
            if (key != null)
            {
                _rsaKey = (RSA)key;
            }
            else
            {
                throw new ArgumentNullException(nameof(key));
            }
        }

        // Disallow access to the parameters of the formatter.
        public override string Parameters
        {
            get { return null; }
            set {; }
        }

        // Create the encrypted key exchange data from the specified input
        // data. This method uses the RSA class only. To
        // support additional providers or provide custom decryption logic,
        // add logic to this member.
        public override byte[] DecryptKeyExchange(byte[] rgbData)
        {
            byte[] decryptedBytes = null;

            if (_rsaKey != null)
            {
                if (_rsaKey is RSA rsa)
                {
                    decryptedBytes = rsa.Decrypt(rgbData, RSAEncryptionPadding.OaepSHA1);
                }
                // Add custom decryption logic here.
            }
            else
            {
                throw new CryptographicUnexpectedOperationException(
                    "Cryptography_MissingKey");
            }

            return decryptedBytes;
        }
    }
}
//
// This code example produces the following output:
//
// Data to encrypt : Sample Contoso encryption application.
// Encrypted data: Khasdf-3248&$%23
// Data decrypted : Sample Contoso encryption application.
// 
// This sample completed successfully; press Enter to exit.

Imports System.Security.Cryptography

Namespace Contoso
    Public Class ContosoDeformatter
        Inherits AsymmetricKeyExchangeDeformatter

        Private rsaKey As RSA

        ' Default constructor.
        Public Sub New()

        End Sub

        ' Constructor with the public key to use for encryption.
        Public Sub New(ByVal key As AsymmetricAlgorithm)
            SetKey(key)
        End Sub

        ' Set the public key for encyption operations.
        Public Overrides Sub SetKey(ByVal key As AsymmetricAlgorithm)
            If (Not key Is Nothing) Then
                rsaKey = CType(key, RSA)
            Else
                Throw New ArgumentNullException("key")
            End If
        End Sub

        ' Disallow access to the parameters of the formatter.
        Public Overrides ReadOnly Property Parameters() As String
            Get
                Return Nothing
            End Get
            Set(ByVal Value As String)

            End Set
        End Property

        ' Create the encrypted key exchange data from the specified input
        ' data. This method uses the RSA class only. To
        ' support additional providers or provide custom decryption logic,
        ' add logic to this member.
        Public Overrides Function DecryptKeyExchange(
            ByVal rgbData() As Byte) As Byte()

            Dim decryptedBytes() As Byte

            If (Not rsaKey Is Nothing) Then
                If (TypeOf (rsaKey) Is RSA) Then
                    Dim rsa As RSA
                    rsa = CType(rsaKey, RSA)

                    decryptedBytes = rsa.Decrypt(rgbData, RSAEncryptionPadding.OaepSHA1)
                End If

                ' Add custom decryption logic here.

            Else
                Throw New CryptographicUnexpectedOperationException(
                    "Cryptography_MissingKey")
            End If

            Return decryptedBytes
        End Function

    End Class
End Namespace
'
' This code example produces the following output:
'
' Data to encrypt : Sample Contoso encryption application.
' Encrypted data: Kh34dfg-(*&834d+3
' Data decrypted : Sample Contoso encryption application.
' 
' This sample completed successfully; press Exit to continue.

注解

非对称密钥交换反格式化程序解密密钥交换数据。

密钥交换允许发送方创建机密信息，例如可在对称加密算法中用作密钥的随机数据，并使用加密将其发送到预期收件人。