Gets information about a CMK.
The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).
The callback for this method is defined as:
'err' is the error that occurred. If there was no error, then 'err' is 'null'.
'err' has 2 properties which hold detailed information:
This method gets information about the CMK specified by KeyId. When the information is returned, the class clears the Key* properties and repopulates them with a single item that contains the CMK's information. The KeyList event is also fired.
The value passed for the KeyId parameter must be the Id or ARN of a CMK, or the name or ARN of an alias, in the current Region. If an ARN is provided, it can be for a CMK or alias in another account so long as the appropriate permissions are in place.