Hi Giorgio,
I hope you are doing well.
In the past, C-MAP only provided their propriety C-98 formatted ENC datasets that required a plugin for ArcMap. Now we have ArcGIS Maritime Server Extension (Maritime Chart Service MCS) customers using C-MAP data. MCS only supports standard S-57/S-63 datasets, so C-MAP must be providing that option now. If your customer requires the use of S-63 encrypted datasets, they will still be required to use MCS to publish map services and bring those into ArcGIS Pro.