SymmetricAlgorithm Class

2013-01-16

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Represents the abstract base class from which all implementations of symmetric algorithms must inherit.

Inheritance Hierarchy

System. . :: . .Object
  Microsoft.SPOT.Cryptoki. . :: . .SessionContainer
    System.Security.Cryptography..::..SymmetricAlgorithm
      System.Security.Cryptography. . :: . .AesCryptoServiceProvider
      System.Security.Cryptography. . :: . .TripleDESCryptoServiceProvider

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

Syntax

'Declaration
Public MustInherit Class SymmetricAlgorithm _
    Inherits SessionContainer

public abstract class SymmetricAlgorithm : SessionContainer

public ref class SymmetricAlgorithm abstract : public SessionContainer

[<AbstractClass>]
type SymmetricAlgorithm =  
    class
        inherit SessionContainer
    end

public abstract class SymmetricAlgorithm extends SessionContainer

The SymmetricAlgorithm type exposes the following members.

Constructors

	Name	Description
	SymmetricAlgorithm	Initializes a new instance of the SymmetricAlgorithm class.

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Properties

	Name	Description
	BlockSize	Gets or sets the block size, in bits, of the cryptographic operation.
	FeedbackSize	Gets or sets the feedback size, in bits, of the cryptographic operation.
	IsDisposed	(Inherited from SessionContainer.)
	IV	Gets or sets the initialization vector (IV) for the symmetric algorithm.
	Key	Gets or sets the secret key for the symmetric algorithm.
	KeySize	Gets or sets the size, in bits, of the secret key used by the symmetric algorithm.
	LegalBlockSizes	Gets the block sizes, in bits, that are supported by the symmetric algorithm.
	LegalKeySizes	Gets the key sizes, in bits, that are supported by the symmetric algorithm.
	MechanismType	Gets the symmetric algorithm type.
	Mode	Gets or sets the mode for operation of the symmetric algorithm.
	Padding	Gets or sets the padding mode used in the symmetric algorithm.
	Session	(Inherited from SessionContainer.)

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Methods

	Name	Description
	Clear	Releases all resources used by the SymmetricAlgorithm class.
	CreateDecryptor() () () ()	Creates a symmetric decryptor object with the current Key property and initialization vector (IV).
	CreateDecryptor(CryptoKey, array<Byte> [] () [] [])	When overridden in a derived class, creates a symmetric decryptor object with the specified Key property and initialization vector (IV).
	CreateEncryptor() () () ()	Creates a symmetric encryptor object with the current Key property and initialization vector (IV).
	CreateEncryptor(CryptoKey, array<Byte> [] () [] [])	When overridden in a derived class, creates a symmetric encryptor object with the specified Key property and initialization vector (IV).
	Dispose() () () ()	(Inherited from SessionContainer.)
	Dispose(Boolean)	Releases the unmanaged resources used by the SymmetricAlgorithm and optionally releases the managed resources. (Overrides SessionContainer. . :: . .Dispose(Boolean).)
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	(Inherited from SessionContainer.)
	GenerateIV	When overridden in a derived class, generates a random initialization vector (IV) to use for the algorithm.
	GenerateKey	When overridden in a derived class, generates a random key (Key) to use for the algorithm.
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	ValidKeySize	Determines whether the specified key size is valid for the current algorithm.

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Fields

	Name	Description
	BlockSizeValue	Represents the block size, in bits, of the cryptographic operation.
	FeedbackSizeValue	Represents the feedback size, in bits, of the cryptographic operation.
	IVValue	Represents the initialization vector (IV) for the symmetric algorithm.
	KeySizeValue	Represents the size, in bits, of the secret key used by the symmetric algorithm.
	KeyValue	Represents the secret key for the symmetric algorithm.
	LegalBlockSizesValue	Specifies the block sizes, in bits, that are supported by the symmetric algorithm.
	LegalKeySizesValue	Specifies the key sizes, in bits, that are supported by the symmetric algorithm.
	m_isDisposed	(Inherited from SessionContainer.)
	m_isSessionClosing	(Inherited from SessionContainer.)
	m_ownsSession	(Inherited from SessionContainer.)
	m_session	(Inherited from SessionContainer.)
	ModeValue	Represents the cipher mode used in the symmetric algorithm.
	OwnsKey	Represents the value that indicates whether the algorithm object owns the key.
	PaddingValue	Represents the padding mode used in the symmetric algorithm.

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Remarks

The classes that derive from the SymmetricAlgorithm class use a chaining mode called cipher block chaining (CBC), which requires a key (Key) and an initialization vector (IV) to perform cryptographic transformations on data. To decrypt data that was encrypted using one of the SymmetricAlgorithm classes, you must set the Key property and the IV property to the same values that were used for encryption. For a symmetric algorithm to be useful, the secret key must be known only to the sender and the receiver.

All cryptographic classes in the .NET Framework that hold sensitive data implement a Clear method. When called, the Clear method overwrites all sensitive data within the object with zeros and then releases the object so that it can be safely garbage collected. When the object has been zeroed and released, you should then call the Dispose method with the disposing parameter set to True to dispose of all managed and unmanaged resources associated with the object.

Thread Safety

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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