Toa Ignika was overworked! As one of tree voluntary Danish geocaching reviewers, work was putting a serious strain on his spare time. He sighed heavily and sat back in his comfy chair. Being a very structured person, he analysed his reviewer tasks whilst sipping a glass of 15 year old port. He was trying to identify tasks that could be automated - and therefore possibly delegated to computer processing...
Quickly, he identified one such task. Often people were submitting caches asking to reserve a coordinate for a geocache. If the spot was available - that is, no other caches were within 161 meters of the requested coordinate - the spot would be reserved. Cache owners could then complete their caches in a calm and orderly way. Before making the reservation, the reviewer task was to check the coordinate against the geocaching.com database containing all cache listings (including even the final locations of mystery- and multi-caches), to make sure no other caches were within 161 meters.
Toa Ignika was an experience programmer and was quickly able to put together a small script to perform this check against the database. The next step was to write an E-mail handler, so that the cache owners could write a small mail to his E-mail address in order to trigger the check. He specified a strict standard format for such E-mails. The subject field should state "Geocache reservation request", while the body of the E-mail should contain only the GC name followed by the coordinate. An example would be: GC5AA321 N55 46.123 E012 19.123.
Then there was the topic of security. If such mails were to fall into the wrong hands - perhaps even into the hands of the evil hacker Mr. X, the consequences could be devastating! Toa therefore decided to use RSA encryption for the communications to and from his E-mail geocaching checker service. The cache owners would encrypt the E-mail body (containing the GC code and the proposed coordinate) with a public key before sending it.
Similarly, he would encrypt any response with the corresponding private key. This way the cache owner would know that the message really originated from his service.
Based on the experience from this security breach, Toa Ignika proceeded to create a very safe public/private key pair for his E-mail service. The public key can be seen below:
n=699368141754282989015166578765505731532486189062401474467883367017264835998597253568382379477630329739753346075592819279477921689373743833991225619539709650114049038114437711088532606867827090304103291730477523986532453335427216168112186191192372517337080880089473422436455619626388315682858454062832805344171005568875774058278124741879878366713328707384056376417345130791242607044966298305642184156033755924442335545275097858347677547221602325383728997809538537192962572166192696275863299792091164530736796879605961258802421189918694001348304543473093979535365214896352152446704761199783059632368548655123439637249799235289728191963294700700901686317381053767548936262252852412846784671325630938515838827816901669194223182188298203155310553846604894296747224957039917678820249305624404678566538621631928465517093969003453224327732073558874449452813207435863855240579809819913566088261485511051255801340196974275937851239231980538866532612883984924906776804580673044821882727672277677808802576436885110933819124477380930277858489695003049917366406140087190348408034766652481079192206084602867092831097986213200961687565221158187187143981327196577742010555759977584396970495494099450816673680480967793398629937910610886610872318593847
e=17
All things complete, it was time do perform some tests. Toa quickly thought of Hr. Vænge in Værløse as an ideal beta-tester. He had, over the years, really created a lot of work as he frequently asked to have new coordinates reserved. Furthermore, Toa knew that Hr. Vænge would be eager to try such a service - especially as it used RSA encryption.
Hr. Vænge of course quickly agreed and created a test message with the coordinates of his newest cache. However, he purposely used a random GC-code along with the correct coordinates.
Hr. Vænge's E-mail to Toa Ignika is shown below:
From: Hr. Vænge, Værløse
To: Toa Ignika, Billund
Subject: Geocache reservation request
5766922910654870937624083172743173602625020394184421207099189842846993061438307484810101258986513976120344582123361838008329395753802109479552631847845112587299083262309212559677899919344167840009781114737770949935088279227235880429844949244207773707602124381839096350479785612636485116534584160918104506773213063825695052850721250963120799032549828291301569776473986292474209642447995946498530816663584291465294540382073674233388575892428519920226722319458295884490259054875352045706300627809901522917231203548632659410041275034669599981283433729261891053909477250185498864554149544189044634713841519877631317580829729616224798219007782024984050202283983775440012285576782414152420385953701889005877715764497872491535352718320123600446435677052096083524193161692153531905564890998463825745807635490476751142028228506723912323442429548860341584900135809637200862071205279738140462445625192754324872517472620808468523060319152005012694049316863057356306623843848513047156087359395626409877102065210239931099605882031147609524455620254529269261951785618925893037766204670424777694972527352748693329188813924592808389757123719947286787966672940578432157701488664386837374163618090349713336312984980553998112315380151222272
A few minutes later, Hr. Vænge received the following E-mail
From: Toa Ignika, Billund
To: Hr. Vænge, Værløse
Subject: Geocache reservation response
687697296753303939496997245330778949904914747290199237493052127757370256068039451288989968019742109532582997260881353841254316467541452234234685598470940736784635436970894848345169963297921735812215598393104773575198836528301754705763033113415751639712296589322427807636195813590511717990597962055387021372915756793580864151784022929336931242764330806772319710729701493245182492208004008757288896212745491514008366316028301349382430260660378397331433387395671407485537452327115998055360402531488151447638486817120588199963051579885338890156842795440610572863196994261136136614205273673277209230075992467959585779802277856575285512576542583382863885446475248279140597474046130207834014719189168561509613239526856595369704143600326017860120729592000643651863486237779714019434759244835118904831739081544339462282257982988797984438350324833797904496273830883382304376968261876248529799503250183704615261460885090064030277994690692874245357086713220063551634531105405408965869937922692952194678899257338637632244811086394662033623955800805138386748441474583153942156758105389446907095331178865696838456919493564818788145428301678960692139832616347903396511575632616401727319907736458267237520985041325957651947206315603428908577277908825
What a fantastic service. Fast, efficient, and it allows Toa Ignika more time to go geocaching for himself. Most importantly, the service is completely safe... - (or is it?)
Geochecker
