HashAlgorithm Class
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Represents the base class from which all implementations of cryptographic hash algorithms must derive.
System.Security.Cryptography::HashAlgorithm
System.Security.Cryptography::KeyedHashAlgorithm
System.Security.Cryptography::SHA1
System.Security.Cryptography::SHA256
Assembly: mscorlib (in mscorlib.dll)
The HashAlgorithm type exposes the following members.
| Name | Description | |
|---|---|---|
 | CanReuseTransform | Gets a value indicating whether the current transform can be reused. |
| CanTransformMultipleBlocks | When overridden in a derived class, gets a value indicating whether multiple blocks can be transformed. |
| Hash | Gets the value of the computed hash code. |
| HashSize | Gets the size, in bits, of the computed hash code. |
| InputBlockSize | When overridden in a derived class, gets the input block size. |
| OutputBlockSize | When overridden in a derived class, gets the output block size. |
| Name | Description | |
|---|---|---|
 | Clear | Releases all resources used by the HashAlgorithm class. |
| ComputeHash(array<Byte>) | Computes the hash value for the specified byte array. |
| ComputeHash(Stream) | Computes the hash value for the specified Stream object. |
| ComputeHash(array<Byte>, Int32, Int32) | Computes the hash value for the specified region of the specified byte array. |
 | Dispose | Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources. |
| Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
| 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.) |
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| HashCore | When overridden in a derived class, routes data written to the object into the hash algorithm for computing the hash. |
| HashFinal | When overridden in a derived class, finalizes the hash computation after the last data is processed by the cryptographic stream object. |
| Initialize | Initializes an implementation of the HashAlgorithm class. |
| MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
| 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. |
| TransformFinalBlock | Computes the hash value for the specified region of the specified byte array. |
| Name | Description | |
|---|---|---|
 | HashSizeValue | Represents the size, in bits, of the computed hash code. |
| HashValue | Represents the value of the computed hash code. |
| State | Represents the state of the hash computation. |
| Name | Description | |
|---|---|---|
  | IDisposable::Dispose | Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources. |
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 InheritorsWhen you inherit from the HashAlgorithm class, you must override the following members: HashCore and HashFinal.