HMAC HMAC HMAC HMAC Class

Definition

Represents the abstract class from which all implementations of Hash-based Message Authentication Code (HMAC) must derive.

public ref class HMAC abstract : System::Security::Cryptography::KeyedHashAlgorithm
[System.Runtime.InteropServices.ComVisible(true)]
public abstract class HMAC : System.Security.Cryptography.KeyedHashAlgorithm
type HMAC = class
    inherit KeyedHashAlgorithm
Public MustInherit Class HMAC
Inherits KeyedHashAlgorithm
Inheritance
Derived
Attributes

Remarks

A Hash-based Message Authentication Code (HMAC) can be used to determine whether a message sent over an insecure channel has been tampered with, provided that the sender and receiver share a secret key. The sender computes the hash value for the original data and sends both the original data and the HMAC as a single message. The receiver recomputes the hash value on the received message and checks that the computed hash value matches the transmitted hash value.

HMAC can be used with any iterative cryptographic hash function, such as MD5 or SHA-1, in combination with a secret shared key. The cryptographic strength of HMAC depends on the properties of the underlying hash function.

Any change to the data or the hash value results in a mismatch, because knowledge of the secret key is required to change the message and reproduce the correct hash value. Therefore, if the original and computed hash values match, the message is authenticated.

Constructors

HMAC() HMAC() HMAC() HMAC()

Initializes a new instance of the HMAC class.

Properties

BlockSizeValue BlockSizeValue BlockSizeValue BlockSizeValue

Gets or sets the block size to use in the hash value.

CanReuseTransform CanReuseTransform CanReuseTransform CanReuseTransform

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

(Inherited from HashAlgorithm)
CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks

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

(Inherited from HashAlgorithm)
Hash Hash Hash Hash

Gets the value of the computed hash code.

(Inherited from HashAlgorithm)
HashName HashName HashName HashName

Gets or sets the name of the hash algorithm to use for hashing.

HashSize HashSize HashSize HashSize

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

(Inherited from HashAlgorithm)
InputBlockSize InputBlockSize InputBlockSize InputBlockSize

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

(Inherited from HashAlgorithm)
Key Key Key Key

Gets or sets the key to use in the hash algorithm.

OutputBlockSize OutputBlockSize OutputBlockSize OutputBlockSize

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

(Inherited from HashAlgorithm)

Methods

Clear() Clear() Clear() Clear()

Releases all resources used by the HashAlgorithm class.

(Inherited from HashAlgorithm)
ComputeHash(Byte[]) ComputeHash(Byte[]) ComputeHash(Byte[]) ComputeHash(Byte[])

Computes the hash value for the specified byte array.

(Inherited from HashAlgorithm)
ComputeHash(Byte[], Int32, Int32) ComputeHash(Byte[], Int32, Int32) ComputeHash(Byte[], Int32, Int32) ComputeHash(Byte[], Int32, Int32)

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

(Inherited from HashAlgorithm)
ComputeHash(Stream) ComputeHash(Stream) ComputeHash(Stream) ComputeHash(Stream)

Computes the hash value for the specified Stream object.

(Inherited from HashAlgorithm)
Create() Create() Create() Create()

Creates an instance of the default implementation of a Hash-based Message Authentication Code (HMAC).

Create(String) Create(String) Create(String) Create(String)

Creates an instance of the specified implementation of a Hash-based Message Authentication Code (HMAC).

Dispose() Dispose() Dispose() Dispose()

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

(Inherited from HashAlgorithm)
Dispose(Boolean) Dispose(Boolean) Dispose(Boolean) Dispose(Boolean)

Releases the unmanaged resources used by the HMAC class when a key change is legitimate and optionally releases the managed resources.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32)

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

HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>)
HashFinal() HashFinal() HashFinal() HashFinal()

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

Initialize() Initialize() Initialize() Initialize()

Initializes an instance of the default implementation of HMAC.

MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)
TransformBlock(Byte[], Int32, Int32, Byte[], Int32) TransformBlock(Byte[], Int32, Int32, Byte[], Int32) TransformBlock(Byte[], Int32, Int32, Byte[], Int32) 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.

(Inherited from HashAlgorithm)
TransformFinalBlock(Byte[], Int32, Int32) TransformFinalBlock(Byte[], Int32, Int32) TransformFinalBlock(Byte[], Int32, Int32) TransformFinalBlock(Byte[], Int32, Int32)

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

(Inherited from HashAlgorithm)
TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) Inherited from HashAlgorithm
TryHashFinal(Span<Byte>, Int32) TryHashFinal(Span<Byte>, Int32) TryHashFinal(Span<Byte>, Int32) TryHashFinal(Span<Byte>, Int32)

Fields

HashSizeValue HashSizeValue HashSizeValue HashSizeValue

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

(Inherited from HashAlgorithm)
HashValue HashValue HashValue HashValue

Represents the value of the computed hash code.

(Inherited from HashAlgorithm)
KeyValue KeyValue KeyValue KeyValue

The key to use in the hash algorithm.

(Inherited from KeyedHashAlgorithm)
State State State State

Represents the state of the hash computation.

(Inherited from HashAlgorithm)

Explicit Interface Implementations

IDisposable.Dispose() IDisposable.Dispose() IDisposable.Dispose() IDisposable.Dispose()

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

(Inherited from HashAlgorithm)

Applies to

See also