DESCryptoServiceProvider Class
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DESCryptoServiceProvider Class

 

Defines a wrapper object to access the cryptographic service provider (CSP) version of the Data Encryption Standard (DES) algorithm. This class cannot be inherited.

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

System.Object
  System.Security.Cryptography.SymmetricAlgorithm
    System.Security.Cryptography.DES
      System.Security.Cryptography.DESCryptoServiceProvider

[ComVisibleAttribute(true)]
public sealed class DESCryptoServiceProvider : DES

NameDescription
System_CAPS_pubmethodDESCryptoServiceProvider()

Initializes a new instance of the DESCryptoServiceProvider class.

NameDescription
System_CAPS_pubpropertyBlockSize

Gets or sets the block size, in bits, of the cryptographic operation.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubpropertyFeedbackSize

Gets or sets the feedback size, in bits, of the cryptographic operation.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubpropertyIV

Gets or sets the initialization vector (IV) for the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubpropertyKey

Gets or sets the secret key for the Data Encryption Standard (DES) algorithm.(Inherited from DES.)

System_CAPS_pubpropertyKeySize

Gets or sets the size, in bits, of the secret key used by the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubpropertyLegalBlockSizes

Gets the block sizes, in bits, that are supported by the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubpropertyLegalKeySizes

Gets the key sizes, in bits, that are supported by the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubpropertyMode

Gets or sets the mode for operation of the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubpropertyPadding

Gets or sets the padding mode used in the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

NameDescription
System_CAPS_pubmethodClear()

Releases all resources used by the SymmetricAlgorithm class.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubmethodCreateDecryptor()

Creates a symmetric decryptor object with the current Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.)

System_CAPS_pubmethodCreateDecryptor(Byte[], Byte[])

Creates a symmetric Data Encryption Standard (DES) decryptor object with the specified key (Key) and initialization vector (IV).(Overrides SymmetricAlgorithm.CreateDecryptor(Byte[], Byte[]).)

System_CAPS_pubmethodCreateEncryptor()

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

System_CAPS_pubmethodCreateEncryptor(Byte[], Byte[])

Creates a symmetric Data Encryption Standard (DES) encryptor object with the specified key (Key) and initialization vector (IV).(Overrides SymmetricAlgorithm.CreateEncryptor(Byte[], Byte[]).)

System_CAPS_pubmethodDispose()

Releases all resources used by the current instance of the SymmetricAlgorithm class.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGenerateIV()

Generates a random initialization vector (IV) to use for the algorithm.(Overrides SymmetricAlgorithm.GenerateIV().)

System_CAPS_pubmethodGenerateKey()

Generates a random key (Key) to be used for the algorithm.(Overrides SymmetricAlgorithm.GenerateKey().)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubmethodValidKeySize(Int32)

Determines whether the specified key size is valid for the current algorithm.(Inherited from SymmetricAlgorithm.)

This algorithm supports a key length of 64 bits.

The following code example uses DESCryptoServiceProvider (an implementation of DES) with the specified key (Key) and initialization vector (IV) to encrypt a file specified by inName. It then outputs the encrypted result to the file specified by outName.

private static void EncryptData(String inName, String outName, byte[] desKey, byte[] desIV)
 {    
     //Create the file streams to handle the input and output files.
     FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read);
     FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, FileAccess.Write);
     fout.SetLength(0);

     //Create variables to help with read and write.
     byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
     long rdlen = 0;              //This is the total number of bytes written.
     long totlen = fin.Length;    //This is the total length of the input file.
     int len;                     //This is the number of bytes to be written at a time.

     DES des = new DESCryptoServiceProvider();          
     CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(desKey, desIV), CryptoStreamMode.Write);

     Console.WriteLine("Encrypting...");

     //Read from the input file, then encrypt and write to the output file.
     while(rdlen < totlen)
     {
         len = fin.Read(bin, 0, 100);
         encStream.Write(bin, 0, len);
         rdlen = rdlen + len;
         Console.WriteLine("{0} bytes processed", rdlen);
     }

     encStream.Close();  
     fout.Close();
     fin.Close();                   
 }

Decryption can be handled in the same way; use CreateDecryptor instead of CreateEncryptor. The same key (Key) and initialization vector (IV) used to encrypt the file must be used to decrypt it.

.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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