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HMACSHA1 Constructor (Byte[])

Initializes a new instance of the HMACSHA1 class with the specified key data.

Namespace:  System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)
new : 
        key:byte[] -> HMACSHA1

Parameters

key
Type: System.Byte[]

The secret key for HMACSHA1 encryption. The key can be any length, but if it is more than 64 bytes long it is hashed (using SHA-1) to derive a 64-byte key. Therefore, the recommended size of the secret key is 64 bytes.

ExceptionCondition
ArgumentNullException

The key parameter is a null reference (Nothing in Visual Basic).

HMACSHA1 is a type of keyed hash algorithm that is constructed from the SHA1 hash function and used as an HMAC, or hash-based message authentication code. The HMAC process mixes a secret key with the message data, hashes the result with the hash function, mixes that hash value with the secret key again, and then applies the hash function a second time. The output hash is 160 bits (20 bytes) in length.

NoteNote

This constructor creates an unmanaged instance of the algorithm by using the SHA1CryptoServiceProvider class.

For an example of how to use this constructor, see the HMACSHA1 class.

.NET Framework

Supported in: 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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