HMAC.Create Method

Definition

Namespace:

System.Security.Cryptography

Assemblies:

netstandard.dll, System.Security.Cryptography.dll

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

Overloads

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

Create()

Source:

HMAC.cs

Caution

The default implementation of this cryptography algorithm is not supported.

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

C#

[System.Obsolete("The default implementation of this cryptography algorithm is not supported.", DiagnosticId="SYSLIB0007", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
public static System.Security.Cryptography.HMAC Create();

Returns

HMAC

A new SHA-1 instance, unless the default settings have been changed by using the <cryptoClass> element.

Attributes

ObsoleteAttribute

Exceptions

PlatformNotSupportedException

.NET Core 2.0 - 3.1 and .NET 5 and later: In all cases.

Remarks

This method is obsolete in .NET 5 and later versions.

By default, this overload uses the SHA-1 implementation of HMAC. If you want to specify a different implementation, use the Create(String) overload, which lets you specify an algorithm name, instead.

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

Create(String)

Source:

HMAC.cs

Caution

Cryptographic factory methods accepting an algorithm name are obsolete. Use the parameterless Create factory method on the algorithm type instead.

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

C#

[System.Obsolete("Cryptographic factory methods accepting an algorithm name are obsolete. Use the parameterless Create factory method on the algorithm type instead.", DiagnosticId="SYSLIB0045", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
public static System.Security.Cryptography.HMAC? Create(string algorithmName);

Parameters

algorithmName

String

The HMAC implementation to use. The following table shows the valid values for the algorithmName parameter and the algorithms they map to.

Parameter value	Implements
System.Security.Cryptography.HMAC	HMACSHA1
System.Security.Cryptography.KeyedHashAlgorithm	HMACSHA1
HMACMD5	HMACMD5
System.Security.Cryptography.HMACMD5	HMACMD5
HMACRIPEMD160	HMACRIPEMD160
System.Security.Cryptography.HMACRIPEMD160	HMACRIPEMD160
HMACSHA1	HMACSHA1
System.Security.Cryptography.HMACSHA1	HMACSHA1
HMACSHA256	HMACSHA256
System.Security.Cryptography.HMACSHA256	HMACSHA256
HMACSHA384	HMACSHA384
System.Security.Cryptography.HMACSHA384	HMACSHA384
HMACSHA512	HMACSHA512
System.Security.Cryptography.HMACSHA512	HMACSHA512
MACTripleDES	MACTripleDES
System.Security.Cryptography.MACTripleDES	MACTripleDES

Returns

HMAC

A new instance of the specified HMAC implementation.

Attributes

ObsoleteAttribute

Remarks

HMAC supports a number of hash algorithms, including MD5, SHA-1, SHA-256, and RIPEMD160. For the full list, see the supported values for the algorithmName parameter.

Due to collision problems with MD5 and SHA-1, Microsoft recommends a security model based on SHA-256 or better.