AesCng::Key Property
Gets or sets the key for the AesCng algorithm.
Assembly: System.Core (in System.Core.dll)
If you've created the AesCng object using an existing persisted key, when you read the value of the Key property, an attempt to export the key will be made. In this case, if the key is not exportable, a CryptographicException will be thrown.
In addition to that, if you set the value of the Key property, the persisted key will no longer be used and a temporary key will be used instead. If you need to use the persisted key again, a new instance of AesCng class needs to be created.
Available since 4.6.2