HashAlgorithm Class

Definition

public ref class HashAlgorithm abstract : IDisposable, System::Security::Cryptography::ICryptoTransform

public ref class HashAlgorithm abstract : IDisposable

public ref class HashAlgorithm abstract : System::Security::Cryptography::ICryptoTransform

public abstract class HashAlgorithm : IDisposable, System.Security.Cryptography.ICryptoTransform

public abstract class HashAlgorithm : IDisposable

public abstract class HashAlgorithm : System.Security.Cryptography.ICryptoTransform

[System.Runtime.InteropServices.ComVisible(true)]public abstract class HashAlgorithm : System.Security.Cryptography.ICryptoTransform

type HashAlgorithm = class    interface IDisposable    interface ICryptoTransform

type HashAlgorithm = class    interface IDisposable

type HashAlgorithm = class    interface ICryptoTransform    interface IDisposable

[<System.Runtime.InteropServices.ComVisible(true)>]type HashAlgorithm = class    interface ICryptoTransform    interface IDisposable

[<System.Runtime.InteropServices.ComVisible(true)>]type HashAlgorithm = class    interface IDisposable    interface ICryptoTransform

Public MustInherit Class HashAlgorithmImplements ICryptoTransform, IDisposable

Public MustInherit Class HashAlgorithmImplements IDisposable

Public MustInherit Class HashAlgorithmImplements ICryptoTransform

Inheritance

Object

HashAlgorithm

Derived

System.Security.Cryptography.KeyedHashAlgorithm

System.Security.Cryptography.MD5

System.Security.Cryptography.RIPEMD160

System.Security.Cryptography.SHA1

System.Security.Cryptography.SHA256

More…

Attributes

ComVisibleAttribute

Implements

IDisposableICryptoTransform

Examples

The following code example computes theSHA256 hash for an array. This example assumes that there is a predefined byte arraydataArray[].SHA256 is a derived class ofHashAlgorithm.

HashAlgorithm sha = SHA256.Create();byte[] result = sha.ComputeHash(dataArray);

Dim sha As SHA256 = SHA256.Create()Dim result As Byte() = sha.ComputeHash(dataArray)

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.

Due to collision problems with SHA-1, Microsoft recommends a security model based on SHA-256 or better.

Notes to Implementers

When you inherit from theHashAlgorithm class, you must override the following members:HashCore(Byte[], Int32, Int32) andHashFinal().

See also

• Cryptographic Services