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.
Assembly: mscorlib (in mscorlib.dll)
System.Security.Cryptography.SymmetricAlgorithm
System.Security.Cryptography.DES
System.Security.Cryptography.DESCryptoServiceProvider
| Name | Description | |
|---|---|---|
![]() | DESCryptoServiceProvider() | Initializes a new instance of the DESCryptoServiceProvider class. |
| Name | Description | |
|---|---|---|
![]() | BlockSize | Gets or sets the block size, in bits, of the cryptographic operation.(Inherited from SymmetricAlgorithm.) |
![]() | FeedbackSize | Gets or sets the feedback size, in bits, of the cryptographic operation.(Inherited from SymmetricAlgorithm.) |
![]() | IV | Gets or sets the initialization vector (IV) for the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | Key | |
![]() | KeySize | Gets or sets the size, in bits, of the secret key used by the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | LegalBlockSizes | Gets the block sizes, in bits, that are supported by the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | LegalKeySizes | Gets the key sizes, in bits, that are supported by the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | Mode | Gets or sets the mode for operation of the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | Padding | Gets or sets the padding mode used in the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
| Name | Description | |
|---|---|---|
![]() | Clear() | Releases all resources used by the SymmetricAlgorithm class.(Inherited from SymmetricAlgorithm.) |
![]() | CreateDecryptor() | Creates a symmetric decryptor object with the current Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.) |
![]() | CreateDecryptor(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()).) |
![]() | CreateEncryptor() | Creates a symmetric encryptor object with the current Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.) |
![]() | CreateEncryptor(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()).) |
![]() | Dispose() | Releases all resources used by the current instance of the SymmetricAlgorithm class.(Inherited from SymmetricAlgorithm.) |
![]() | Equals(Object) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | GenerateIV() | Generates a random initialization vector (IV) to use for the algorithm.(Overrides SymmetricAlgorithm.GenerateIV().) |
![]() | GenerateKey() | Generates a random key (Key) to be used for the algorithm.(Overrides SymmetricAlgorithm.GenerateKey().) |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetType() | |
![]() | ToString() | Returns a string that represents the current object.(Inherited from Object.) |
![]() | ValidKeySize(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 Shared Sub EncryptData(inName As String, outName As String, _ desKey() As Byte, desIV() As Byte) 'Create the file streams to handle the input and output files. Dim fin As New FileStream(inName, FileMode.Open, FileAccess.Read) Dim fout As New FileStream(outName, FileMode.OpenOrCreate, _ FileAccess.Write) fout.SetLength(0) 'Create variables to help with read and write. Dim bin(4096) As Byte 'This is intermediate storage for the encryption. Dim rdlen As Long = 0 'This is the total number of bytes written. Dim totlen As Long = fin.Length 'Total length of the input file. Dim len As Integer 'This is the number of bytes to be written at a time. Dim des As New DESCryptoServiceProvider() Dim encStream As 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, 4096) encStream.Write(bin, 0, len) rdlen = Convert.ToInt32(rdlen + len / des.BlockSize * des.BlockSize) Console.WriteLine("Processed {0} bytes, {1} bytes total", len, _ rdlen) End While encStream.Close() End Sub
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.
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.

