TripleDESCryptoServiceProvider.CreateEncryptor Method

Definition

Namespace:

System.Security.Cryptography

Assemblies:

netstandard.dll, System.Security.Cryptography.dll

Creates a symmetric encryptor object.

Overloads

CreateEncryptor()	Creates a symmetric encryptor object with the current Key property and initialization vector (IV).
CreateEncryptor(Byte[], Byte[])	Creates a symmetric TripleDES encryptor object with the specified key (Key) and initialization vector (IV).

CreateEncryptor()

Source:

TripleDESCryptoServiceProvider.Wrap.cs

Creates a symmetric encryptor object with the current Key property and initialization vector (IV).

C#

public override System.Security.Cryptography.ICryptoTransform CreateEncryptor();

Returns

ICryptoTransform

A symmetric encryptor object.

Remarks

If the current Key property is null, the GenerateKey method is called to create a new random Key. If the current IV property is null, the GenerateIV method is called to create a new random IV.

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

CreateEncryptor(Byte[], Byte[])

Source:

TripleDESCryptoServiceProvider.Wrap.cs

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

C#

public override System.Security.Cryptography.ICryptoTransform CreateEncryptor(byte[] rgbKey, byte[]? rgbIV);

Parameters

rgbKey

Byte[]

The secret key to use for the symmetric algorithm.

rgbIV

Byte[]

The initialization vector to use for the symmetric algorithm.

Note: The initialization vector must be 8 bytes long. If it is longer than 8 bytes, it is truncated and an exception is not thrown. Before you call CreateEncryptor(Byte[], Byte[]), check the length of the initialization vector and throw an exception if it is too long.

Returns

ICryptoTransform

A symmetric TripleDES encryptor object.

Exceptions

CryptographicException

The value of the Mode property is OFB.

-or-

The value of the Mode property is CFB and the value of the FeedbackSize property is not 8.

-or-

An invalid key size was used.

-or-

The algorithm key size was not available.

Examples

The following code example creates a TripleDESCryptoServiceProvider object and uses it to encrypt and decrypt data in a file.

C#

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

class TrippleDESCSPSample
{

    static void Main()
    {
        try
        {
            // Create a new TripleDESCryptoServiceProvider object
            // to generate a key and initialization vector (IV).
            TripleDESCryptoServiceProvider tDESalg = new TripleDESCryptoServiceProvider();

            // Create a string to encrypt.
            string sData = "Here is some data to encrypt.";
            string FileName = "CText.txt";

            // Encrypt text to a file using the file name, key, and IV.
            EncryptTextToFile(sData, FileName, tDESalg.Key, tDESalg.IV);

            // Decrypt the text from a file using the file name, key, and IV.
            string Final = DecryptTextFromFile(FileName, tDESalg.Key, tDESalg.IV);

            // Display the decrypted string to the console.
            Console.WriteLine(Final);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }

    public static void EncryptTextToFile(String Data, String FileName, byte[] Key, byte[] IV)
    {
        try
        {
            // Create or open the specified file.
            FileStream fStream = File.Open(FileName,FileMode.OpenOrCreate);

            // Create a CryptoStream using the FileStream
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(fStream,
                new TripleDESCryptoServiceProvider().CreateEncryptor(Key,IV),
                CryptoStreamMode.Write);

            // Create a StreamWriter using the CryptoStream.
            StreamWriter sWriter = new StreamWriter(cStream);

            // Write the data to the stream
            // to encrypt it.
            sWriter.WriteLine(Data);

            // Close the streams and
            // close the file.
            sWriter.Close();
            cStream.Close();
            fStream.Close();
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
        }
        catch(UnauthorizedAccessException  e)
        {
            Console.WriteLine("A file access error occurred: {0}", e.Message);
        }
    }

    public static string DecryptTextFromFile(String FileName, byte[] Key, byte[] IV)
    {
        try
        {
            // Create or open the specified file.
            FileStream fStream = File.Open(FileName, FileMode.OpenOrCreate);

            // Create a CryptoStream using the FileStream
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(fStream,
                new TripleDESCryptoServiceProvider().CreateDecryptor(Key,IV),
                CryptoStreamMode.Read);

            // Create a StreamReader using the CryptoStream.
            StreamReader sReader = new StreamReader(cStream);

            // Read the data from the stream
            // to decrypt it.
            string val = sReader.ReadLine();

            // Close the streams and
            // close the file.
            sReader.Close();
            cStream.Close();
            fStream.Close();

            // Return the string.
            return val;
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
        catch(UnauthorizedAccessException  e)
        {
            Console.WriteLine("A file access error occurred: {0}", e.Message);
            return null;
        }
    }
}

The following code example creates a TripleDESCryptoServiceProvider object and uses it to encrypt and decrypt data in memory.

C#

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

class TrippleDESCSPSample
{

    static void Main()
    {
        try
        {
            // Create a new TripleDESCryptoServiceProvider object
            // to generate a key and initialization vector (IV).
            TripleDESCryptoServiceProvider tDESalg = new TripleDESCryptoServiceProvider();

            // Create a string to encrypt.
            string sData = "Here is some data to encrypt.";

            // Encrypt the string to an in-memory buffer.
            byte[] Data = EncryptTextToMemory(sData, tDESalg.Key, tDESalg.IV);

            // Decrypt the buffer back to a string.
            string Final = DecryptTextFromMemory(Data, tDESalg.Key, tDESalg.IV);

            // Display the decrypted string to the console.
            Console.WriteLine(Final);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }

    public static byte[] EncryptTextToMemory(string Data,  byte[] Key, byte[] IV)
    {
        try
        {
            // Create a MemoryStream.
            MemoryStream mStream = new MemoryStream();

            // Create a CryptoStream using the MemoryStream
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(mStream,
                new TripleDESCryptoServiceProvider().CreateEncryptor(Key, IV),
                CryptoStreamMode.Write);

            // Convert the passed string to a byte array.
            byte[] toEncrypt = new ASCIIEncoding().GetBytes(Data);

            // Write the byte array to the crypto stream and flush it.
            cStream.Write(toEncrypt, 0, toEncrypt.Length);
            cStream.FlushFinalBlock();

            // Get an array of bytes from the
            // MemoryStream that holds the
            // encrypted data.
            byte[] ret = mStream.ToArray();

            // Close the streams.
            cStream.Close();
            mStream.Close();

            // Return the encrypted buffer.
            return ret;
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
    }

    public static string DecryptTextFromMemory(byte[] Data,  byte[] Key, byte[] IV)
    {
        try
        {
            // Create a new MemoryStream using the passed
            // array of encrypted data.
            MemoryStream msDecrypt = new MemoryStream(Data);

            // Create a CryptoStream using the MemoryStream
            // and the passed key and initialization vector (IV).
            CryptoStream csDecrypt = new CryptoStream(msDecrypt,
                new TripleDESCryptoServiceProvider().CreateDecryptor(Key, IV),
                CryptoStreamMode.Read);

            // Create buffer to hold the decrypted data.
            byte[] fromEncrypt = new byte[Data.Length];

            // Read the decrypted data out of the crypto stream
            // and place it into the temporary buffer.
            csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length);

            //Convert the buffer into a string and return it.
            return new ASCIIEncoding().GetString(fromEncrypt);
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
    }
}

Remarks

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

See also

• Cryptographic Services