TripleDES Class

Definition

Namespace:

System.Security.Cryptography

Assembly:

System.Security.Cryptography.dll

Source:

TripleDES.cs

Represents the base class for Triple Data Encryption Standard algorithms from which all TripleDES implementations must derive.

public ref class TripleDES abstract : System::Security::Cryptography::SymmetricAlgorithm

public abstract class TripleDES : System.Security.Cryptography.SymmetricAlgorithm

type TripleDES = class
    inherit SymmetricAlgorithm

Public MustInherit Class TripleDES
Inherits SymmetricAlgorithm

Inheritance

Object

SymmetricAlgorithm

TripleDES

Derived

System.Security.Cryptography.TripleDESCng

System.Security.Cryptography.TripleDESCryptoServiceProvider

Examples

The following code example method uses TripleDESCryptoServiceProvider 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.

void EncryptData( String^ inName, String^ outName, array<Byte>^tdesKey, array<Byte>^tdesIV )
{
   
   //Create the file streams to handle the input and output files.
   FileStream^ fin = gcnew FileStream( inName,FileMode::Open,FileAccess::Read );
   FileStream^ fout = gcnew FileStream( outName,FileMode::OpenOrCreate,FileAccess::Write );
   fout->SetLength( 0 );
   
   //Create variables to help with read and write.
   array<Byte>^bin = gcnew array<Byte>(100);
   long rdlen = 0; //This is the total number of bytes written.

   long totlen = (long)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.

   TripleDESCryptoServiceProvider^ tdes = gcnew TripleDESCryptoServiceProvider;
   CryptoStream^ encStream = gcnew CryptoStream( fout,tdes->CreateEncryptor( tdesKey, tdesIV ),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();
}

private static void EncryptData(string inName, string outName, byte[] tdesKey, byte[] tdesIV)
{
    //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.

    TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
    CryptoStream encStream = new CryptoStream(fout, tdes.CreateEncryptor(tdesKey, tdesIV), 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();
}

Private Shared Sub EncryptData(inName As String, outName As String, _
   tdesKey() As Byte, tdesIV() 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(100) 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 'This is the total length of the input file.
    Dim len As Integer 'This is the number of bytes to be written at a time.
    Dim tdes As New TripleDESCryptoServiceProvider()
    Dim encStream As New CryptoStream(fout, _
       tdes.CreateEncryptor(tdesKey, tdesIV), 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)
    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.

Remarks

TripleDES uses three successive iterations of the DES algorithm. It can use either two or three 56-bit keys.

Note

A newer symmetric encryption algorithm, Advanced Encryption Standard (AES), is available. Consider using the Aes class and its derived classes instead of the TripleDES class. Use TripleDES only for compatibility with legacy applications and data.

This algorithm supports key lengths from 128 bits to 192 bits in increments of 64 bits.

Constructors

TripleDES()

Initializes a new instance of the TripleDES class.

Fields

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)

Properties

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 for the Cipher Feedback (CFB) and Output Feedback (OFB) cipher modes. (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 TripleDES algorithm.
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)

Methods

Clear()	Releases all resources used by the SymmetricAlgorithm class. (Inherited from SymmetricAlgorithm)
Create()	Creates an instance of a cryptographic object to perform the TripleDES algorithm.
Create(String)	Obsolete. Creates an instance of a cryptographic object to perform the specified implementation of the TripleDES 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)
DecryptCbc(Byte[], Byte[], PaddingMode)	Decrypts data using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
DecryptCbc(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, PaddingMode)	Decrypts data using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
DecryptCbc(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, PaddingMode)	Decrypts data into the specified buffer, using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
DecryptCfb(Byte[], Byte[], PaddingMode, Int32)	Decrypts data using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
DecryptCfb(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, PaddingMode, Int32)	Decrypts data using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
DecryptCfb(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32)	Decrypts data into the specified buffer, using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
DecryptEcb(Byte[], PaddingMode)	Decrypts data using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
DecryptEcb(ReadOnlySpan<Byte>, PaddingMode)	Decrypts data using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
DecryptEcb(ReadOnlySpan<Byte>, Span<Byte>, PaddingMode)	Decrypts data into the specified buffer, using ECB mode with the specified padding mode. (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)
EncryptCbc(Byte[], Byte[], PaddingMode)	Encrypts data using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
EncryptCbc(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, PaddingMode)	Encrypts data using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
EncryptCbc(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, PaddingMode)	Encrypts data into the specified buffer, using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
EncryptCfb(Byte[], Byte[], PaddingMode, Int32)	Encrypts data using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
EncryptCfb(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, PaddingMode, Int32)	Encrypts data using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
EncryptCfb(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32)	Encrypts data into the specified buffer, using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
EncryptEcb(Byte[], PaddingMode)	Encrypts data using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
EncryptEcb(ReadOnlySpan<Byte>, PaddingMode)	Encrypts data using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
EncryptEcb(ReadOnlySpan<Byte>, Span<Byte>, PaddingMode)	Encrypts data into the specified buffer, using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
Equals(Object)	Determines whether the specified object is equal to the current object. (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)
GetCiphertextLengthCbc(Int32, PaddingMode)	Gets the length of a ciphertext with a given padding mode and plaintext length in CBC mode. (Inherited from SymmetricAlgorithm)
GetCiphertextLengthCfb(Int32, PaddingMode, Int32)	Gets the length of a ciphertext with a given padding mode and plaintext length in CFB mode. (Inherited from SymmetricAlgorithm)
GetCiphertextLengthEcb(Int32, PaddingMode)	Gets the length of a ciphertext with a given padding mode and plaintext length in ECB mode. (Inherited from SymmetricAlgorithm)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsWeakKey(Byte[])	Determines whether the specified key is weak.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)
TryDecryptCbc(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, Int32, PaddingMode)	Attempts to decrypt data into the specified buffer, using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
TryDecryptCbcCore(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32)	When overridden in a derived class, attempts to decrypt data into the specified buffer, using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
TryDecryptCfb(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, Int32, PaddingMode, Int32)	Attempts to decrypt data into the specified buffer, using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
TryDecryptCfbCore(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32, Int32)	When overridden in a derived class, attempts to decrypt data into the specified buffer, using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
TryDecryptEcb(ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32)	Attempts to decrypt data into the specified buffer, using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
TryDecryptEcbCore(ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32)	When overridden in a derived class, attempts to decrypt data into the specified buffer, using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
TryEncryptCbc(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, Int32, PaddingMode)	Attempts to encrypt data into the specified buffer, using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
TryEncryptCbcCore(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32)	When overridden in a derived class, attempts to encrypt data into the specified buffer, using CBC mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
TryEncryptCfb(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, Int32, PaddingMode, Int32)	Attempts to encrypt data into the specified buffer, using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
TryEncryptCfbCore(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32, Int32)	When overridden in a derived class, attempts to encrypt data into the specified buffer, using CFB mode with the specified padding mode and feedback size. (Inherited from SymmetricAlgorithm)
TryEncryptEcb(ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32)	Attempts to encrypt data into the specified buffer, using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
TryEncryptEcbCore(ReadOnlySpan<Byte>, Span<Byte>, PaddingMode, Int32)	When overridden in a derived class, attempts to encrypt data into the specified buffer, using ECB mode with the specified padding mode. (Inherited from SymmetricAlgorithm)
ValidKeySize(Int32)	Determines whether the specified key size is valid for the current algorithm. (Inherited from SymmetricAlgorithm)

See also

• Aes
• Cryptographic Services