Calendar Lock PEA - Free Encrypted iCalendar Application
Calendar Lock PEA is an easy to use open source calendar tool that you can use for keeping track of your events. It includes a customizable month, week and day view where you can add and edit appointments. The calendars can be stored with various cloud providers.
Confidentiality through On-the-fly encryption: The content is decrypted only when requested and only in memory, never on disk.
Compatible with iCalendar data (ics files), such as those used in Google Calendar, Apple Calendar, Microsoft Outlook and other areas.
Save your calendars in the cloud and upload new versions using several cloud providers. All data remain encrypted during this process.
Protects the integrity of the data by an authenticated encryption. This guarantees that the data has not been manipulated.
Add a second factor besides the password and protect your data additionally with a key file. Store this key file wherever you want.
Virtual keyboard against Keyloggers
Provides an internal on-screen keyboard to protect against hardware keyloggers as well against some software keyloggers.
Platform independent: Runs on all systems with a Java runtime environment
- Uses a memory-hard key derivation function that defends custom-hardware attacks
- Adjustability for colors, font sizes, calendar view
- All source code is open source, including the libraries used
- Measures the quality of new passwords during input by a password strength meter.
Indicates their strength by colored bars
- Combines System Entropy with its own Entropy Source
- Offers character tables to enlarge the character set of passwords
The program is small and consists of a single archive file. Installation is not required.
Calendar data should always be available and never be lost, which is one reason they are often stored in the cloud.
At the same time, calendars contain very sensitive and personal information: Appointments allow a precise profile of when you are where, after-work events also reveal something about personal preferences and relationships, medical consultations about your health condition... This is why they are a worthwhile target for snooping:
- Many commercial services are trying to access this data to create user profiles.
- Government agencies are trying to gather information about the behavior of potential dissidents.
- Scammers are just buying and selling these data.
It is not just about not giving potential burglars information about when you are not at home. The protection of calendar data is also a social responsibility: often, calendar data not only reveals private information about oneself, but also about others. And a world in which big Internet companies, criminals and intelligence agencies have gigantic amounts of information at their disposal is a scary world for almost everyone.
This application intends to keep calendar data as private as possible. At the same time, the aim is to keep the additional effort required for this as low as possible.
Download Options for Calendar Lock PEA 1.4:
Cipher (EAX-Mode): Threefish, AES-256
Hash Function: Blake2b, SHA-3
If the Calendar Lock PEA does not meet your expectations, take a look at the Alternatives to Calendar Lock PEA.
Recurrence Rule: Like in most other iCalendar applications, only the most common recurrence rules can be defined. The full set of possible recurrence rules would make the setting extremly complicated and is unlikely to be used. Some properties may still be added, but on the whole the recurrence rule is complete - at least as complete as intended.
The main views (daily, weekly, monthly) are implemented. A yearly overview and an event list should be added.
It is not intended to implement all the features defined in RFC 5545.
Some featuresFeatures like multi-lingual support, ATTENDEE, CATEGORY
The accessibility support is to be improved.
The graphic user interface in the historical style of the 90s will remain.
The Long-time Goal of this Application
It's nice to have calendars protected on a PC. But as long as mobile devices automatically pass such data to companies like Google, Microsoft or Apple, that's not much.
In principle, it is possible to synchronize these data between different devices without ever storing them unencrypted on any device or any cloud server. Necessary for this is an application on each of these systems, which indeed displays this data, but always stores and synchronizes them in encrypted form. That's a lot of work. And you have to start from scratch. Synchronization standards such as the CalDAV protocol completely ignore user privacy and rule out the possibility of encryption in principle.
The Calendar Lock PEA is also meant as a very first step towards this long term goal. Any help to achieve this goal is welcome: bug reports, reviews, programming, or even donation.
AcknowledgementThanks to all who have improved, tested or reviewed Calendar Lock PEA and other PEAs
How to use
Start the Jar Archive
You need OpenJDK, Java Runtime Environment (JRE) or something similar (at least 1.8). On most systems there is at least one available.
These PEAs are single Java jar archives, a file with the extension "jar". If you are familiar with jar archives, you can skip the following part.
Initialization: First Start
The first time you start the Calendar Lock PEA, the program will initialize. You are asked for a password,
a calendar name and color.
You can reset the password later in the menu.