This method saves the currently selected public certificate to a file.
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:
Note: This method is present for backwards compatibility. It is recommended to use ExportCertificate to export both public and private certificates and keys.
This method saves the public certificate of the currently selected certificate in PEM (Base64) format to the location specified by the FileName parameter.
If the destination file exists it is overwritten.