The exportKey() method takes a CryptoKey object as input and exports it in an external, portable format.
Note that for a key to be exportable, it must have been created with the extractable flag set to true.
|format||string||Defines the data format the key should be exported in. Currently supported formats: raw.|
|key||CryptoKey||The key to export.|
A Promise that resolves to a new ArrayBuffer containing the key.
|InvalidAccessError||Raised when trying to export a non-extractable key.|
|NotSupportedError||Raised when trying to export in an unknown format.|
|TypeError||Raised when trying to use an invalid format.|