DES Class
Represents the base class for the Data Encryption Standard (DES) algorithm from which all DES implementations must derive.
Assembly: mscorlib (in mscorlib.dll)
System.Security.Cryptography.SymmetricAlgorithm
System.Security.Cryptography.DES
System.Security.Cryptography.DESCryptoServiceProvider
| Name | Description | |
|---|---|---|
![]() | DES() | Initializes a new instance of the DES 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 | Gets or sets the secret key for the Data Encryption Standard (DES) algorithm.(Overrides 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.) |
![]() ![]() | Create() | Creates an instance of a cryptographic object to perform the Data Encryption Standard (DES) algorithm. |
![]() ![]() | Create(String) | Creates an instance of a cryptographic object to perform the specified implementation of the Data Encryption Standard (DES) algorithm. |
![]() | CreateDecryptor() | Creates a symmetric decryptor object with the current Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.) |
![]() | CreateDecryptor(Byte(), Byte()) | When overridden in a derived class, creates a symmetric decryptor object with the specified Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.) |
![]() | CreateEncryptor() | Creates a symmetric encryptor object with the current Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.) |
![]() | CreateEncryptor(Byte(), Byte()) | When overridden in a derived class, creates a symmetric encryptor object with the specified Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.) |
![]() | Dispose() | Releases all resources used by the current instance of the SymmetricAlgorithm class.(Inherited from SymmetricAlgorithm.) |
![]() | Dispose(Boolean) | Releases the unmanaged resources used by the SymmetricAlgorithm and optionally releases the managed resources.(Inherited from SymmetricAlgorithm.) |
![]() | Equals(Object) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | Finalize() | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.) |
![]() | GenerateIV() | When overridden in a derived class, generates a random initialization vector (IV) to use for the algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | GenerateKey() | When overridden in a derived class, generates a random key (Key) to use for the algorithm. (Inherited from SymmetricAlgorithm.) |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetType() | |
![]() ![]() | IsSemiWeakKey(Byte()) | Determines whether the specified key is semi-weak. |
![]() ![]() | IsWeakKey(Byte()) | Determines whether the specified key is weak. |
![]() | MemberwiseClone() | |
![]() | 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.) |
| Name | Description | |
|---|---|---|
![]() | BlockSizeValue | Represents the block size, in bits, of the cryptographic operation.(Inherited from SymmetricAlgorithm.) |
![]() | FeedbackSizeValue | Represents the feedback size, in bits, of the cryptographic operation.(Inherited from SymmetricAlgorithm.) |
![]() | IVValue | Represents the initialization vector (IV) for the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | KeySizeValue | Represents the size, in bits, of the secret key used by the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | KeyValue | Represents the secret key for the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | LegalBlockSizesValue | Specifies the block sizes, in bits, that are supported by the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | LegalKeySizesValue | Specifies the key sizes, in bits, that are supported by the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | ModeValue | Represents the cipher mode used in the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
![]() | PaddingValue | Represents the padding mode used in the symmetric algorithm.(Inherited from SymmetricAlgorithm.) |
This algorithm supports a key length of 64 bits.
Note |
|---|
A newer asymmetric encryption algorithm, Advanced Encryption Standard (AES), is available. Consider using the Aes class instead of the DES class. Use DES only for compatibility with legacy applications and data. |
The following code example uses DESCryptoServiceProvider (an implementation of DES) to encrypt a string to an in-memory buffer. It then decrypts and displays the round-tripped string.
Imports System Imports System.IO Imports System.Security.Cryptography Class TripleDESCryptoServiceProviderExample Public Shared Sub Main() Try Dim original As String = "Here is some data to encrypt!" ' Create a new instance of the TripleDESCryptoServiceProvider ' class. This generates a new key and initialization ' vector (IV). Using myTripleDESCryptoServiceProvider As New TripleDESCryptoServiceProvider() ' Encrypt the string to an array of bytes. Dim encrypted As Byte() = EncryptStringToBytes(original, myTripleDESCryptoServiceProvider.Key, myTripleDESCryptoServiceProvider.IV) ' Decrypt the bytes to a string. Dim roundtrip As String = DecryptStringFromBytes(encrypted, myTripleDESCryptoServiceProvider.Key, myTripleDESCryptoServiceProvider.IV) 'Display the original data and the decrypted data. Console.WriteLine("Original: {0}", original) Console.WriteLine("Round Trip: {0}", roundtrip) End Using Catch e As Exception Console.WriteLine("Error: {0}", e.Message) End Try End Sub 'Main Shared Function EncryptStringToBytes(ByVal plainText As String, ByVal Key() As Byte, ByVal IV() As Byte) As Byte() ' Check arguments. If plainText Is Nothing OrElse plainText.Length <= 0 Then Throw New ArgumentNullException("plainText") End If If Key Is Nothing OrElse Key.Length <= 0 Then Throw New ArgumentNullException("Key") End If If IV Is Nothing OrElse IV.Length <= 0 Then Throw New ArgumentNullException("Key") End If Dim encrypted() As Byte ' Create an TripleDESCryptoServiceProvider object ' with the specified key and IV. Using tdsAlg As New TripleDESCryptoServiceProvider() tdsAlg.Key = Key tdsAlg.IV = IV ' Create a decrytor to perform the stream transform. Dim encryptor As ICryptoTransform = tdsAlg.CreateEncryptor(tdsAlg.Key, tdsAlg.IV) ' Create the streams used for encryption. Using msEncrypt As New MemoryStream() Using csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write) Using swEncrypt As New StreamWriter(csEncrypt) 'Write all data to the stream. swEncrypt.Write(plainText) End Using encrypted = msEncrypt.ToArray() End Using End Using End Using ' Return the encrypted bytes from the memory stream. Return encrypted End Function 'EncryptStringToBytes Shared Function DecryptStringFromBytes(ByVal cipherText() As Byte, ByVal Key() As Byte, ByVal IV() As Byte) As String ' Check arguments. If cipherText Is Nothing OrElse cipherText.Length <= 0 Then Throw New ArgumentNullException("cipherText") End If If Key Is Nothing OrElse Key.Length <= 0 Then Throw New ArgumentNullException("Key") End If If IV Is Nothing OrElse IV.Length <= 0 Then Throw New ArgumentNullException("Key") End If ' Declare the string used to hold ' the decrypted text. Dim plaintext As String = Nothing ' Create an TripleDESCryptoServiceProvider object ' with the specified key and IV. Using tdsAlg As New TripleDESCryptoServiceProvider tdsAlg.Key = Key tdsAlg.IV = IV ' Create a decrytor to perform the stream transform. Dim decryptor As ICryptoTransform = tdsAlg.CreateDecryptor(tdsAlg.Key, tdsAlg.IV) ' Create the streams used for decryption. Using msDecrypt As New MemoryStream(cipherText) Using csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read) Using srDecrypt As New StreamReader(csDecrypt) ' Read the decrypted bytes from the decrypting stream ' and place them in a string. plaintext = srDecrypt.ReadToEnd() End Using End Using End Using End Using Return plaintext End Function 'DecryptStringFromBytes End Class
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.





