HMAC.Key Property
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Gets or sets the key to use in the hash algorithm.
Namespace: System.Security.Cryptography
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Overrides Property Key As Byte()
public override byte[] Key { get; set; }
Property Value
Type: array<System.Byte[]
The key to use in the hash algorithm.
Exceptions
| Exception | Condition |
|---|---|
| CryptographicException | An attempt is made to change the Key property after hashing has begun. |
Remarks
This property is the key for the keyed hash algorithm.
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.
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
See Also