TripleDES Class

 

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

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


[ComVisibleAttribute(true)]
public abstract class TripleDES : SymmetricAlgorithm

NameDescription
System_CAPS_protmethodTripleDES()

Initializes a new instance of the TripleDES 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 TripleDES algorithm.(Overrides SymmetricAlgorithm.Key.)

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_pubmethodSystem_CAPS_staticCreate()

Creates an instance of a cryptographic object to perform the TripleDES algorithm.

System_CAPS_pubmethodSystem_CAPS_staticCreate(String)

Creates an instance of a cryptographic object to perform the specified implementation of the TripleDES algorithm.

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[])

When overridden in a derived class, creates a symmetric decryptor object with the specified Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.)

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[])

When overridden in a derived class, creates a symmetric encryptor object with the specified Key property and initialization vector (IV).(Inherited from SymmetricAlgorithm.)

System_CAPS_pubmethodDispose()

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

System_CAPS_protmethodDispose(Boolean)

Releases the unmanaged resources used by the SymmetricAlgorithm and optionally releases the managed resources.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubmethodEquals(Object)

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

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGenerateIV()

When overridden in a derived class, generates a random initialization vector (IV) to use for the algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_pubmethodGenerateKey()

When overridden in a derived class, generates a random key (Key) to use for the algorithm. (Inherited from SymmetricAlgorithm.)

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_pubmethodSystem_CAPS_staticIsWeakKey(Byte[])

Determines whether the specified key is weak.

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(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.)

NameDescription
System_CAPS_protfieldBlockSizeValue

Represents the block size, in bits, of the cryptographic operation.(Inherited from SymmetricAlgorithm.)

System_CAPS_protfieldFeedbackSizeValue

Represents the feedback size, in bits, of the cryptographic operation.(Inherited from SymmetricAlgorithm.)

System_CAPS_protfieldIVValue

Represents the initialization vector (IV) for the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_protfieldKeySizeValue

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

System_CAPS_protfieldKeyValue

Represents the secret key for the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_protfieldLegalBlockSizesValue

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

System_CAPS_protfieldLegalKeySizesValue

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

System_CAPS_protfieldModeValue

Represents the cipher mode used in the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

System_CAPS_protfieldPaddingValue

Represents the padding mode used in the symmetric algorithm.(Inherited from SymmetricAlgorithm.)

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

System_CAPS_noteNote

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.

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.

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();                     
}

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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