HashAlgorithm Class
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HashAlgorithm Class

 

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

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


[ComVisibleAttribute(true)]
public abstract class HashAlgorithm : IDisposable, ICryptoTransform

NameDescription
System_CAPS_protmethodHashAlgorithm()

Initializes a new instance of the HashAlgorithm class.

NameDescription
System_CAPS_pubpropertyCanReuseTransform

Gets a value indicating whether the current transform can be reused.

System_CAPS_pubpropertyCanTransformMultipleBlocks

When overridden in a derived class, gets a value indicating whether multiple blocks can be transformed.

System_CAPS_pubpropertyHash

Gets the value of the computed hash code.

System_CAPS_pubpropertyHashSize

Gets the size, in bits, of the computed hash code.

System_CAPS_pubpropertyInputBlockSize

When overridden in a derived class, gets the input block size.

System_CAPS_pubpropertyOutputBlockSize

When overridden in a derived class, gets the output block size.

NameDescription
System_CAPS_pubmethodClear()

Releases all resources used by the HashAlgorithm class.

System_CAPS_pubmethodComputeHash(Byte[])

Computes the hash value for the specified byte array.

System_CAPS_pubmethodComputeHash(Byte[], Int32, Int32)

Computes the hash value for the specified region of the specified byte array.

System_CAPS_pubmethodComputeHash(Stream)

Computes the hash value for the specified Stream object.

System_CAPS_pubmethodSystem_CAPS_staticCreate()

Creates an instance of the default implementation of a hash algorithm.

System_CAPS_pubmethodSystem_CAPS_staticCreate(String)

Creates an instance of the specified implementation of a hash algorithm.

System_CAPS_pubmethodDispose()

Releases all resources used by the current instance of the HashAlgorithm class.

System_CAPS_protmethodDispose(Boolean)

Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources.

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_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_protmethodHashCore(Byte[], Int32, Int32)

When overridden in a derived class, routes data written to the object into the hash algorithm for computing the hash.

System_CAPS_protmethodHashFinal()

When overridden in a derived class, finalizes the hash computation after the last data is processed by the cryptographic stream object.

System_CAPS_pubmethodInitialize()

Initializes an implementation of the HashAlgorithm class.

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_pubmethodTransformBlock(Byte[], Int32, Int32, Byte[], Int32)

Computes the hash value for the specified region of the input byte array and copies the specified region of the input byte array to the specified region of the output byte array.

System_CAPS_pubmethodTransformFinalBlock(Byte[], Int32, Int32)

Computes the hash value for the specified region of the specified byte array.

NameDescription
System_CAPS_protfieldHashSizeValue

Represents the size, in bits, of the computed hash code.

System_CAPS_protfieldHashValue

Represents the value of the computed hash code.

System_CAPS_protfieldState

Represents the state of the hash computation.

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.

The following code example computes the SHA1CryptoServiceProvider hash for an array. This example assumes that there is a predefined byte array dataArray[]. SHA1CryptoServiceProvider is a derived class of HashAlgorithm.

HashAlgorithm sha = new SHA1CryptoServiceProvider();
byte[] result = sha.ComputeHash(dataArray);

.NET Framework
Available since 1.1
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0

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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