RC2CryptoServiceProvider.CreateDecryptor(Byte[], Byte[]) Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
public:
override System::Security::Cryptography::ICryptoTransform ^ CreateDecryptor(cli::array <System::Byte> ^ rgbKey, cli::array <System::Byte> ^ rgbIV);
public override System.Security.Cryptography.ICryptoTransform CreateDecryptor (byte[] rgbKey, byte[]? rgbIV);
public override System.Security.Cryptography.ICryptoTransform CreateDecryptor (byte[] rgbKey, byte[] rgbIV);
override this.CreateDecryptor : byte[] * byte[] -> System.Security.Cryptography.ICryptoTransform
Public Overrides Function CreateDecryptor (rgbKey As Byte(), rgbIV As Byte()) As ICryptoTransform
Parameters
- rgbKey
- Byte[]
The secret key to use for the symmetric algorithm.
- rgbIV
- Byte[]
The initialization vector to use for the symmetric algorithm.
Returns
A symmetric RC2 decryptor object.
Exceptions
An OFB cipher mode was used.
-or-
A CFB cipher mode with a feedback size other than 8 bits was used.
-or-
An invalid key size was used.
-or-
The algorithm key size was not available.
Examples
The following code example encrypts and then decrypts a string.
using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;
namespace RC2CryptoServiceProvider_Examples
{
class MyMainClass
{
public static void Main()
{
// Create a new instance of the RC2CryptoServiceProvider class
// and automatically generate a Key and IV.
RC2CryptoServiceProvider rc2CSP = new RC2CryptoServiceProvider();
Console.WriteLine("Effective key size is {0} bits.", rc2CSP.EffectiveKeySize);
// Get the key and IV.
byte[] key = rc2CSP.Key;
byte[] IV = rc2CSP.IV;
// Get an encryptor.
ICryptoTransform encryptor = rc2CSP.CreateEncryptor(key, IV);
// Encrypt the data as an array of encrypted bytes in memory.
MemoryStream msEncrypt = new MemoryStream();
CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write);
// Convert the data to a byte array.
string original = "Here is some data to encrypt.";
byte[] toEncrypt = Encoding.ASCII.GetBytes(original);
// Write all data to the crypto stream and flush it.
csEncrypt.Write(toEncrypt, 0, toEncrypt.Length);
csEncrypt.FlushFinalBlock();
// Get the encrypted array of bytes.
byte[] encrypted = msEncrypt.ToArray();
///////////////////////////////////////////////////////
// This is where the data could be transmitted or saved.
///////////////////////////////////////////////////////
//Get a decryptor that uses the same key and IV as the encryptor.
ICryptoTransform decryptor = rc2CSP.CreateDecryptor(key, IV);
// Now decrypt the previously encrypted message using the decryptor
// obtained in the above step.
MemoryStream msDecrypt = new MemoryStream(encrypted);
CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read);
// Read the decrypted bytes from the decrypting stream
// and place them in a StringBuilder class.
StringBuilder roundtrip = new StringBuilder();
int b = 0;
do
{
b = csDecrypt.ReadByte();
if (b != -1)
{
roundtrip.Append((char)b);
}
} while (b != -1);
// Display the original data and the decrypted data.
Console.WriteLine("Original: {0}", original);
Console.WriteLine("Round Trip: {0}", roundtrip);
}
}
}
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography
Module Crypto
Sub Main()
' Create a new instance of the RC2CryptoServiceProvider class
' and automatically generate a Key and IV.
Dim rc2CSP As New RC2CryptoServiceProvider()
Console.WriteLine("Effective key size is {0} bits.", rc2CSP.EffectiveKeySize)
' Get the key and IV.
Dim key As Byte() = rc2CSP.Key
Dim IV As Byte() = rc2CSP.IV
' Get an encryptor.
Dim encryptor As ICryptoTransform = rc2CSP.CreateEncryptor(key, IV)
' Encrypt the data as an array of encrypted bytes in memory.
Dim msEncrypt As New MemoryStream()
Dim csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
' Convert the data to a byte array.
Dim original As String = "Here is some data to encrypt."
Dim toEncrypt As Byte() = Encoding.ASCII.GetBytes(original)
' Write all data to the crypto stream and flush it.
csEncrypt.Write(toEncrypt, 0, toEncrypt.Length)
csEncrypt.FlushFinalBlock()
' Get the encrypted array of bytes.
Dim encrypted As Byte() = msEncrypt.ToArray()
'''''''''''''''''''''''''''''''''''''''''''''''''''''''
' This is where the data could be transmitted or saved.
'''''''''''''''''''''''''''''''''''''''''''''''''''''''
'Get a decryptor that uses the same key and IV as the encryptor.
Dim decryptor As ICryptoTransform = rc2CSP.CreateDecryptor(key, IV)
' Now decrypt the previously encrypted message using the decryptor
' obtained in the above step.
Dim msDecrypt As New MemoryStream(encrypted)
Dim csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)
' Read the decrypted bytes from the decrypting stream
' and place them in a StringBuilder class.
Dim roundtrip As New StringBuilder()
Dim b As Integer = 0
Do
b = csDecrypt.ReadByte()
If b <> -1 Then
roundtrip.Append(ChrW(b))
End If
Loop While b <> -1
' Display the original data and the decrypted data.
Console.WriteLine("Original: {0}", original)
Console.WriteLine("Round Trip: {0}", roundtrip)
End Sub
End Module
Remarks
This method is used to decrypt an encrypted message created using the CreateEncryptor overload with the same parameters.
Applies to
See also
.NET
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