Cryptography and Security
- Data Destroyer
A program to wipe single or multiple files, that is, to overwrite their contents so that the data in them cannot be recovered.
- Cryptosystem ME6
An encryption program which uses a symmetric key encryption algorithm
(with 500-bit keys) to encrypt information in files for secure storage
- Backup Modified Files
Backs up files in a folder and selected subfolders of that folder.
- Stego PNG
Another steganographic application (but easier to use) for hiding a
message file of any type within a PNG or a BMP image file.
- Email Encryption End-to-End
A program for sending and receiving encrypted email messages (optionally
with attached file). It uses a symmetric key method and works with any email program.
- Types of Calendar
Lunar, solar, lunisolar, rule-based, etc.
- The Julian and the Gregorian Calendars
The Julian Calendar, the Gregorian reform and its adoption, astronomical year numbering,
the Julian and the Gregorian Proleptic Calendars, and the accuracy of calendars.
- The ISO 8601 Date Format
A note concerning date formats, especially the ISO 8601 date format.
- Julian Day Numbers
The nature and origin of the Julian day number system.
- Chronological Julian Date
An explanation of the concept with examples of use.
- The Hermetic Leap Week Calendar
A calendar with an integral number of 7-day weeks in each year, and which stays in sync with the seasonal year.
- The Hermetic Lunar Week Calendar
A solilunar calendar which avoids the problem of rescheduling with each new year.
- The Archetypes Calendar
An accurate lunar calendar with (mostly) weeks of 10 days.
- Why Seven Days in a Week?
Why not six or eight?
- The Structure of the Chinese Calendar
How the Chinese Calendar depends on the times of astronomical events.
- The Maya Calendar
Links to an explanation of Maya and European Dates, the correlation problem, and the yearbearer systems.
- The Liberalia Triday Calendar
- The Meyer-Palmen Solilunar Calendar
- Writings by Others
Articles by renowned calendrical scientists Karl Palmen,
Simon Cassidy, Duncan Steel, Lance Latham, the
Böhm brothers and others.
- Easy Date Converter
A conversion program which gives you the day of the week for a date, the
Julian day number and more, and allows date arithmetic: adding a number
of days to a date, etc., with or without inclusion of weekend days. In
English and German.
- Equinoxes, Solstices and Cross-Quarter Days
For calculating accurate dates and times of equinoxes, solstices and the
Celtic cross-quarter days for any year in the range 1 CE through
3000 CE (for both hemispheres).
- Lunar Calendars and Eclipse Finder
Software for conversion among dates in the Common Era and Julian
Calendars and dates in several lunar calendars. The program also finds
the dates, times and durations of solar and lunar eclipses.
- Chinese Calendrics
Software for converting between Chinese and Western dates and for
obtaining other information such as the dates of Chinese New Year's Day
for any year.
- Julian-Gregorian-Dee Date Calculator
Converts between Julian, Gregorian, Dee and Dee-Cecil calendar dates in
various formats, and adds and subtracts a number of days, weeks, months
and years to or from a given date.
- Mayan Calendrics
Converts among Maya and European dates in various calendar systems. In English and German.
- Identical Calendar Years
How long do you have to wait before you can re-use that old wall calendar that you like so much?
- Printable Calendar
A modest utility to help you keep track of things to do.
- Printable Hermetic Lunar Week Calendar
Same same but different.