- Reference
Definition
- Namespace:
- System.Security.Cryptography
- Assembly:
- System.Security.Cryptography.Primitives.dll
- Assembly:
- System.Security.Cryptography.dll
- Assembly:
- mscorlib.dll
- Assembly:
- netstandard.dll
- Source:
- HashAlgorithm.cs
- Source:
- HashAlgorithm.cs
- Source:
- HashAlgorithm.cs
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Represents the base class from which all implementations of cryptographic hash algorithms must derive.
public ref class HashAlgorithm abstract : IDisposable, System::Security::Cryptography::ICryptoTransformpublic ref class HashAlgorithm abstract : IDisposablepublic ref class HashAlgorithm abstract : System::Security::Cryptography::ICryptoTransformpublic abstract class HashAlgorithm : IDisposable, System.Security.Cryptography.ICryptoTransformpublic abstract class HashAlgorithm : IDisposablepublic abstract class HashAlgorithm : System.Security.Cryptography.ICryptoTransform[System.Runtime.InteropServices.ComVisible(true)]public abstract class HashAlgorithm : System.Security.Cryptography.ICryptoTransformtype HashAlgorithm = class interface IDisposable interface ICryptoTransformtype HashAlgorithm = class interface IDisposabletype 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 ICryptoTransformPublic MustInherit Class HashAlgorithmImplements ICryptoTransform, IDisposablePublic MustInherit Class HashAlgorithmImplements IDisposablePublic MustInherit Class HashAlgorithmImplements ICryptoTransform- Inheritance
- 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 the SHA256 hash for an array. This example assumes that there is a predefined byte array dataArray[]. SHA256 is a derived class of HashAlgorithm.
HashAlgorithm^ sha = SHA256::Create();array<Byte>^ result = sha->ComputeHash( dataArray );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 SHA1, Microsoft recommends a security model based on SHA256 or better.
Notes to Implementers
When you inherit from the HashAlgorithm class, you must override the following members: HashCore(Byte[], Int32, Int32) and HashFinal().
Constructors
| HashAlgorithm() | Initializes a new instance of the HashAlgorithm class. |
Fields
| 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. |
Properties
| 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. |
Methods
| Clear() | Releases all resources used by the HashAlgorithm class. |
| ComputeHash(Byte[], Int32, Int32) | Computes the hash value for the specified region of the specified byte array. |
| ComputeHash(Byte[]) | Computes the hash value for the specified byte array. |
| ComputeHash(Stream) | Computes the hash value for the specified Stream object. |
| ComputeHashAsync(Stream, CancellationToken) | Asynchronously computes the hash value for the specified Stream object. |
| Create() | Obsolete. Obsolete. Creates an instance of the default implementation of a hash algorithm. |
| Create(String) | Obsolete. Creates an instance of the specified implementation of a hash algorithm. |
| Dispose() | Releases all resources used by the current instance of the HashAlgorithm class. |
| Dispose(Boolean) | 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) |
| GetHashCode() | Serves as the default hash function. (Inherited from Object) |
| GetType() | Gets the Type of the current instance. (Inherited from Object) |
| HashCore(Byte[], Int32, Int32) | When overridden in a derived class, routes data written to the object into the hash algorithm for computing the hash. |
| HashCore(ReadOnlySpan<Byte>) | 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 hash algorithm. |
| Initialize() | Resets the hash algorithm to its initial state. |
| 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(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. |
| TransformFinalBlock(Byte[], Int32, Int32) | Computes the hash value for the specified region of the specified byte array. |
| TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) | Attempts to compute the hash value for the specified byte array. |
| TryHashFinal(Span<Byte>, Int32) | Attempts to finalize the hash computation after the last data is processed by the hash algorithm. |
Explicit Interface Implementations
| IDisposable.Dispose() | Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources. |
Applies to
See also
- Cryptographic Services
