RijndaelManaged::CreateEncryptor Method (array<Byte>^, array<Byte>^)

 

Creates a symmetric Rijndael encryptor object with the specified Key and initialization vector (IV).

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

public:
virtual ICryptoTransform^ CreateEncryptor(
	array<unsigned char>^ rgbKey,
	array<unsigned char>^ rgbIV
) override

Parameters

rgbKey
Type: array<System::Byte>^

The secret key to be used for the symmetric algorithm. The key size must be 128, 192, or 256 bits.

rgbIV
Type: array<System::Byte>^

The IV to be used for the symmetric algorithm.

Return Value

Type: System.Security.Cryptography::ICryptoTransform^

A symmetric Rijndael encryptor object.

Exception Condition
ArgumentNullException

The rgbKey parameter is null.

-or-

The rgbIV parameter is null.

CryptographicException

The value of the Mode property is not ECB, CBC, or CFB.

Use the CreateDecryptor overload with the same signature to decrypt the result of this method.

The rgbkey size must be 128, 192, or 256 bits.

The following code examples demonstrates how to encrypt a message using the CreateEncryptor method.

#using <System.dll>

using namespace System;
using namespace System::IO;
using namespace System::Security::Cryptography;


class RijndaelMemoryExample
{
public:
    static array<Byte>^ encryptStringToBytes_AES(String^ plainText, array<Byte>^ Key, array<Byte>^ IV)
    {
        // Check arguments.
        if (!plainText || plainText->Length <= 0)
            throw gcnew ArgumentNullException("plainText");
        if (!Key || Key->Length <= 0)
            throw gcnew ArgumentNullException("Key");
        if (!IV  || IV->Length <= 0)
            throw gcnew ArgumentNullException("IV");

        // Declare the streams used
        // to encrypt to an in memory
        // array of bytes.
		MemoryStream^   msEncrypt;
        CryptoStream^   csEncrypt;
        StreamWriter^   swEncrypt;

        // Declare the RijndaelManaged object
        // used to encrypt the data.
        RijndaelManaged^ aesAlg;

        try
        {
            // Create a RijndaelManaged object
            // with the specified key and IV.
            aesAlg = gcnew RijndaelManaged();
			aesAlg->Padding = PaddingMode::PKCS7;
            aesAlg->Key = Key;
            aesAlg->IV = IV;

            // Create an encryptor to perform the stream transform.
            ICryptoTransform^ encryptor = aesAlg->CreateEncryptor(aesAlg->Key, aesAlg->IV);

            // Create the streams used for encryption.
            msEncrypt = gcnew MemoryStream();
			csEncrypt = gcnew CryptoStream(msEncrypt, encryptor, CryptoStreamMode::Write);
            swEncrypt = gcnew StreamWriter(csEncrypt);

            //Write all data to the stream.
            swEncrypt->Write(plainText);
			swEncrypt->Flush();
			csEncrypt->FlushFinalBlock();
			msEncrypt->Flush();
        }
        finally
        {
            // Clean things up.

            // Close the streams.
            if(swEncrypt)
                swEncrypt->Close();
            if (csEncrypt)
                csEncrypt->Close();


            // Clear the RijndaelManaged object.
            if (aesAlg)
                aesAlg->Clear();
        }

        // Return the encrypted bytes from the memory stream.
        return msEncrypt->ToArray();
    }

    static String^ decryptStringFromBytes_AES(array<Byte>^ cipherText, array<Byte>^ Key, array<Byte>^ IV)
    {
        // Check arguments.
        if (!cipherText || cipherText->Length <= 0)
            throw gcnew ArgumentNullException("cipherText");
        if (!Key || Key->Length <= 0)
            throw gcnew ArgumentNullException("Key");
        if (!IV || IV->Length <= 0)
            throw gcnew ArgumentNullException("IV");

        // TDeclare the streams used
        // to decrypt to an in memory
        // array of bytes.
        MemoryStream^ msDecrypt;
        CryptoStream^ csDecrypt;
        StreamReader^ srDecrypt;

        // Declare the RijndaelManaged object
        // used to decrypt the data.
        RijndaelManaged^ aesAlg;

        // Declare the string used to hold
        // the decrypted text.
        String^ plaintext;

        try
        {
            // Create a RijndaelManaged object
            // with the specified key and IV.
            aesAlg = gcnew RijndaelManaged();
			aesAlg->Padding = PaddingMode::PKCS7;
            aesAlg->Key = Key;
            aesAlg->IV = IV;

            // Create a decrytor to perform the stream transform.
			ICryptoTransform^ decryptor = aesAlg->CreateDecryptor(aesAlg->Key, aesAlg->IV);

            // Create the streams used for decryption.
            msDecrypt = gcnew MemoryStream(cipherText);
			csDecrypt = gcnew CryptoStream(msDecrypt, decryptor, CryptoStreamMode::Read);
            srDecrypt = gcnew StreamReader(csDecrypt);

            // Read the decrypted bytes from the decrypting stream
            // and place them in a string.
            plaintext = srDecrypt->ReadToEnd();
        }
        finally
        {
            // Clean things up.

            // Close the streams.
            if (srDecrypt)
                srDecrypt->Close();
            if (csDecrypt)
                csDecrypt->Close();
            if (msDecrypt)
                msDecrypt->Close();

            // Clear the RijndaelManaged object.
            if (aesAlg)
                aesAlg->Clear();
        }

        return plaintext;
    }
};

int main()
{
    try
    {
        String^ original = "Here is some data to encrypt!";

        // Create a new instance of the RijndaelManaged
        // class.  This generates a new key and initialization
        // vector (IV).
        RijndaelManaged^ myRijndael = gcnew RijndaelManaged();

        // Encrypt the string to an array of bytes.
		array<Byte>^ encrypted = RijndaelMemoryExample::encryptStringToBytes_AES(original, myRijndael->Key, myRijndael->IV);

        // Decrypt the bytes to a string.
        String^ roundtrip = RijndaelMemoryExample::decryptStringFromBytes_AES(encrypted, myRijndael->Key, myRijndael->IV);

        //Display the original data and the decrypted data.
		Console::WriteLine("Original:   {0}", original);
		Console::WriteLine("Round Trip: {0}", roundtrip);
    }
    catch (Exception^ e)
    {
		Console::WriteLine("Error: {0}", e->Message);
    }

	return 0;
}

.NET Framework
Available since 1.1
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