DES.Create Method

Definition

Namespace:

System.Security.Cryptography

Assemblies:

netstandard.dll, System.Security.Cryptography.dll

Creates an instance of a cryptographic object to perform the Data Encryption Standard (DES) algorithm.

Overloads

Create()	Creates an instance of a cryptographic object to perform the Data Encryption Standard (DES) algorithm.
Create(String)	Obsolete. Creates an instance of a cryptographic object to perform the specified implementation of the Data Encryption Standard (DES) algorithm.

Create()

Source:

DES.cs

Creates an instance of a cryptographic object to perform the Data Encryption Standard (DES) algorithm.

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public static System.Security.Cryptography.DES Create();

Returns

DES

A cryptographic object.

Attributes

UnsupportedOSPlatformAttribute

Examples

The following code example shows how to create and use a DES object to encrypt and decrypt data in a file.

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

class DESSample
{
    static void Main()
    {
        try
        {
            byte[] key;
            byte[] iv;

            // Create a new DES object to generate a random key
            // and initialization vector (IV).
            using (DES des = DES.Create())
            {
                key = des.Key;
                iv = des.IV;
            }

            // Create a string to encrypt.
            string original = "Here is some data to encrypt.";
            // The name/path of the file to write.
            string filename = "CText.enc";

            // Encrypt the string to a file.
            EncryptTextToFile(original, filename, key, iv);

            // Decrypt the file back to a string.
            string decrypted = DecryptTextFromFile(filename, key, iv);

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

    public static void EncryptTextToFile(string text, string path, byte[] key, byte[] iv)
    {
        try
        {
            // Create or open the specified file.
            using (FileStream fStream = File.Open(path, FileMode.Create))
            // Create a new DES object.
            using (DES des = DES.Create())
            // Create a DES encryptor from the key and IV
            using (ICryptoTransform encryptor = des.CreateEncryptor(key, iv))
            // Create a CryptoStream using the FileStream and encryptor
            using (var cStream = new CryptoStream(fStream, encryptor, CryptoStreamMode.Write))
            {
                // Convert the provided string to a byte array.
                byte[] toEncrypt = Encoding.UTF8.GetBytes(text);

                // Write the byte array to the crypto stream.
                cStream.Write(toEncrypt, 0, toEncrypt.Length);
            }
        }
        catch (CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            throw;
        }
    }

    public static string DecryptTextFromFile(string path, byte[] key, byte[] iv)
    {
        try
        {
            // Open the specified file
            using (FileStream fStream = File.OpenRead(path))
            // Create a new DES object.
            using (DES des = DES.Create())
            // Create a DES decryptor from the key and IV
            using (ICryptoTransform decryptor = des.CreateDecryptor(key, iv))
            // Create a CryptoStream using the FileStream and decryptor
            using (var cStream = new CryptoStream(fStream, decryptor, CryptoStreamMode.Read)) 
            // Create a StreamReader to turn the bytes back into text
            using (StreamReader reader = new StreamReader(cStream, Encoding.UTF8))
            {
                // Read back all of the text from the StreamReader, which receives
                // the decrypted bytes from the CryptoStream, which receives the
                // encrypted bytes from the FileStream.
                return reader.ReadToEnd();
            }
        }
        catch (CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            throw;
        }
    }
}

The following code example shows how to create and use a DES object to encrypt and decrypt data in memory.

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

class DESSample2
{
    static void Main()
    {
        try
        {
            byte[] key;
            byte[] iv;

            // Create a new DES object to generate a random key
            // and initialization vector (IV).
            using (DES des = DES.Create())
            {
                key = des.Key;
                iv = des.IV;
            }

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

            // Encrypt the string to an in-memory buffer.
            byte[] encrypted = EncryptTextToMemory(original, key, iv);

            // Decrypt the buffer back to a string.
            string decrypted = DecryptTextFromMemory(encrypted, key, iv);

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

    public static byte[] EncryptTextToMemory(string text, byte[] key, byte[] iv)
    {
        try
        {
            // Create a MemoryStream.
            using (MemoryStream mStream = new MemoryStream())
            {
                // Create a new DES object.
                using (DES des = DES.Create())
                // Create a DES encryptor from the key and IV
                using (ICryptoTransform encryptor = des.CreateEncryptor(key, iv))
                // Create a CryptoStream using the MemoryStream and encryptor
                using (var cStream = new CryptoStream(mStream, encryptor, CryptoStreamMode.Write))
                {
                    // Convert the provided string to a byte array.
                    byte[] toEncrypt = Encoding.UTF8.GetBytes(text);

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

                    // Ending the using statement for the CryptoStream completes the encryption.
                }

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

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

    public static string DecryptTextFromMemory(byte[] encrypted, byte[] key, byte[] iv)
    {
        try
        {
            // Create a buffer to hold the decrypted data.
            // DES-encrypted data will always be slightly bigger than the decrypted data.
            byte[] decrypted = new byte[encrypted.Length];
            int offset = 0;

            // Create a new MemoryStream using the provided array of encrypted data.
            using (MemoryStream mStream = new MemoryStream(encrypted))
            {
                // Create a new DES object.
                using (DES des = DES.Create())
                // Create a DES decryptor from the key and IV
                using (ICryptoTransform decryptor = des.CreateDecryptor(key, iv))
                // Create a CryptoStream using the MemoryStream and decryptor
                using (var cStream = new CryptoStream(mStream, decryptor, CryptoStreamMode.Read))
                {
                    // Keep reading from the CryptoStream until it finishes (returns 0).
                    int read = 1;

                    while (read > 0)
                    {
                        read = cStream.Read(decrypted, offset, decrypted.Length - offset);
                        offset += read;
                    }
                }
            }

            // Convert the buffer into a string and return it.
            return Encoding.UTF8.GetString(decrypted, 0, offset);
        }
        catch (CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            throw;
        }
    }
}

Remarks

Creates an instance of the DES object that can be used for encrypting and decrypting data.

See also

• Cryptographic Services

Create(String)

Source:

DES.cs

Caution

Cryptographic factory methods accepting an algorithm name are obsolete. Use the parameterless Create factory method on the algorithm type instead.

Creates an instance of a cryptographic object to perform the specified implementation of the Data Encryption Standard (DES) algorithm.

[System.Obsolete("Cryptographic factory methods accepting an algorithm name are obsolete. Use the parameterless Create factory method on the algorithm type instead.", DiagnosticId="SYSLIB0045", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
public static System.Security.Cryptography.DES? Create(string algName);

Parameters

algName

String

The name of the specific implementation of DES to use.

Returns

DES

A cryptographic object.

Attributes

ObsoleteAttribute

See also

• Cryptographic Services