GC-Codec

This is a utility app for geocache owners to create the Signature for the electronic log book. So far geocaches have been logged by writing the username into a little log book that was contained in the geocache container. This new idea of logging replaces the paper booklet by sending an SMS to the owner instead. The geocache container contains a little printout of a QR code instead of the log book. The QR code contains all necessary information to create the SMS. This app is used to create a electronic signature that is part of the QR string.

How to create the Signature with the GC-Codec App:
1) Enter your phonenumber with country code ("+4365012345678") in the field "Enter raw text" without ("")
2) Enter the GC code ("GC12345") as listed on the geocache website in the field "Enter key" without ("")
As result you get the Signature which is then used as last part for creating the QR code with the QR code generator.

How to create the QR code with the QR code generator:
The QR string to be entered in the QR code generator contains following information:
GC code,GC name,Latitude,Longitude,Signature
1) Use a QR code generator (http://goqr.me/de/)
2) The QR code must contain following fields separated by commas without spaces around the commas and without (""):
a) GC code ("GC12345"), as listed on the geocache website
b) GC name ("The name of your GC"), as listed on the geocache website
c) Latitude ("N(S)DD:MM.MMM") as listed on the geocache website, attention the degree sign must be replaced by the colon
d) Longitude ("E(W)DD:MM.MMM") as listed on the geocache website, attention the degree sign must be replaced by the colon
e) Signature ("C12..") the code generated with this app
As an example the entry in the QR code generator should look like this:
GC12345,The name of your GC,N47:14.562,E9:35.667,1CEF234784860EDA

Summary:
Signature = Phonenumber + GC code
QR String = GC code,GC name,Latitude,Longitude,Signature

Apps needed for QR code:
Signature: GC-Codec
QR graphic: QR code generator

How to verify the received SMS:
The SMS sent to the owner has following fields:
GC code,GC name,Username,Signature
The Signature can also be checked with this app, by entering the username in the field "Enter raw text:" and by entering the GC code in the field "Enter key:". The signature generated should match the signature received.

Note:
In order to log geocaches with this new system the app GC-Logger is required.