HashAlgorithm Class

Represents the base class from which all implementations of cryptographic hash algorithms must derive.

Inheritance Hierarchy

System.Object
  System.Security.Cryptography.HashAlgorithm
    System.Security.Cryptography.KeyedHashAlgorithm
    System.Security.Cryptography.SHA1
    System.Security.Cryptography.SHA256

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

Syntax

'Declaration
<ComVisibleAttribute(True)> _
Public MustInherit Class HashAlgorithm _
    Implements ICryptoTransform, IDisposable
[ComVisibleAttribute(true)]
public abstract class HashAlgorithm : ICryptoTransform, 
    IDisposable

The HashAlgorithm type exposes the following members.

Constructors

  Name Description
Protected methodSupported by Silverlight for Windows Phone HashAlgorithm Initializes a new instance of the HashAlgorithm class.

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Properties

  Name Description
Public propertySupported by Silverlight for Windows Phone CanReuseTransform Gets a value indicating whether the current transform can be reused.
Public propertySupported by Silverlight for Windows Phone CanTransformMultipleBlocks When overridden in a derived class, gets a value indicating whether multiple blocks can be transformed.
Public propertySupported by Silverlight for Windows Phone Hash Gets the value of the computed hash code.
Public propertySupported by Silverlight for Windows Phone HashSize Gets the size, in bits, of the computed hash code.
Public propertySupported by Silverlight for Windows Phone InputBlockSize When overridden in a derived class, gets the input block size.
Public propertySupported by Silverlight for Windows Phone OutputBlockSize When overridden in a derived class, gets the output block size.

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Methods

  Name Description
Public methodSupported by Silverlight for Windows Phone Clear Releases all resources used by the HashAlgorithm class.
Public methodSupported by Silverlight for Windows Phone ComputeHash(array<Byte[]) Computes the hash value for the specified byte array.
Public methodSupported by Silverlight for Windows Phone ComputeHash(Stream) Computes the hash value for the specified Stream object.
Public methodSupported by Silverlight for Windows Phone ComputeHash(array<Byte[], Int32, Int32) Computes the hash value for the specified region of the specified byte array.
Protected methodSupported by Silverlight for Windows Phone Dispose Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources.
Public methodSupported by Silverlight for Windows Phone Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows Phone Finalize Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone GetType Gets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows Phone HashCore When overridden in a derived class, routes data written to the object into the hash algorithm for computing the hash.
Protected methodSupported by Silverlight for Windows Phone HashFinal When overridden in a derived class, finalizes the hash computation after the last data is processed by the cryptographic stream object.
Public methodSupported by Silverlight for Windows Phone Initialize Initializes an implementation of the HashAlgorithm class.
Protected methodSupported by Silverlight for Windows Phone MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone ToString Returns a string that represents the current object. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone TransformBlock Computes the hash value for the specified region of the input byte array and copies the resulting hash value to the specified region of the output byte array.
Public methodSupported by Silverlight for Windows Phone TransformFinalBlock Computes the hash value for the specified region of the specified byte array.

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Fields

  Name Description
Protected fieldSupported by Silverlight for Windows Phone HashSizeValue Represents the size, in bits, of the computed hash code.
Protected fieldSupported by Silverlight for Windows Phone HashValue Represents the value of the computed hash code.
Protected fieldSupported by Silverlight for Windows Phone State Represents the state of the hash computation.

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Explicit Interface Implementations

  Name Description
Explicit interface implemetationPrivate methodSupported by Silverlight for Windows Phone IDisposable.Dispose Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources.

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Remarks

Hash functions are fundamental to modern cryptography. These functions map binary strings of an arbitrary length to small binary strings of a fixed length, known as hash values. A cryptographic hash function has the property that it is computationally infeasible to find two distinct inputs that hash to the same value. Hash functions are commonly used with digital signatures and for data integrity.

The hash is used as a unique value of fixed size representing a large amount of data. Hashes of two sets of data should match if the corresponding data also matches. Small changes to the data result in large unpredictable changes in the hash.

Notes to Inheritors

When you inherit from the HashAlgorithm class, you must override the following members: HashCore and HashFinal.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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.