About preserve privacy
Since August 1st 2014, you have the possibility to protect your calendar preserves using cryptography. This makes sure that the calendar data and the original calendar URL is encrypted and those with access to this server (both intentionally granted and possible intruders) won't be able to easily break your privacy.
The encryption is based on a password you supply. This password is not stored on this server and it is your responsibility to store or remember it and keep it safe. The password needs to be added to the preserve URL, so you should also trust any cloud calendar readers you are possibly using. Since the data on the server is encrypted based on your password and the password is not stored, it is impossible to help you restore your data if you lose it.
The only downside with the encryption is that it becomes impossible to regularly search the original calendar for new events to store. This is because it is, without your password, impossible to get the original URL or append data to the stored preserve. Instead, the preservation of events is done when your calendar reader accesses the preserve. Thus, in order not to miss any events, you should make sure your calendar reader accesses the preserve regularly enough when using encryption.
All icalfilter features should be accessed using https, so the password nor the calendar contents can be seen by someone trying to spy on the network traffic.
If there is anything you wonder about, don't hesitate to ask. The comments thread on the main page is a great way of giving feedback.
Summary and comparison
Using encryption and https and making sure that your calendar reader accesses the preserve regularly enough, your data should be safe and you shouldn't notice any negative effects.
You are able to enable or disable the encryption on the manage page linked to from the added footer in all your events' descriptions.
|Encrypted preserve||Non-encrypted preserve|
|Data and URL storage||Encrypted using AES with a key derived from your password using PBKDF2||As plain text|
|Preserve update||When accessed by calendar reader||Regularly, every hour|
|Network traffic||You should use https||You should use https|