Want to play a game?
A set of various programming tasks waiting for you. Encryption of input files forces you so solve them sequentially.
Is there a way to store private information publicly on GitHub? The data we upload must be perfectly retrievable but only for the key holder.
Advanced Encryption Standard
The answer might lie with Advanced Encryption Standard (AES) which provides a symmetric encryption for any binary stream. As a demonstration I devised a game that utilizes encryption.
Programming challenge
Here are a series of tasks. They are heavily inspired by some old IPSC problems so if you enjoy this game, you will surely like IPSC as well.
Each input is encrypted with encrypt.sh as
openssl-1.0 aes-256-cbc -in <inFname> -out <outFname> -k <encKey> -base64 -md md5To decrypt a file just add a -d flag to the end of the command. You can also
use JavaScript decryptor below.
By solving a task you get a key to decrypt the official solution and the input of the next task. You can check if your solution is correct by calculating and comparing the first 5 characters of the key’s SHA256 hash.
The first task is encrypted with a two character key (its hash starts with 73475). Find it and you can start! And remember, don’t panic.
| Task | Input | Solution | Hash |
|---|---|---|---|
| 01_run_me.py | download decrypt | decrypt | 2A700 |
| 02_clocks.txt | download decrypt | decrypt | F4A97 |
| 03_play_me.wav | download decrypt | decrypt | F577B |
| 04_chess.txt | download decrypt | decrypt | AA76D |
| 05_image.png | download decrypt | decrypt | 6AEB6 |
Hall of fame
| Task | Username | Signature |
|---|---|---|
| 00 | dcrystalj | 81B26737244D1AA1A254A447F498DE65DCF76486F456C5AAEBE2798AEB838BBF |
| 00 | daiwai | 47CF7E1DB51207914959909DF21FBC486CA601CFEBE4F4BE36804A5C280BFD50 |
| 00 | damir00 | 253DE19E5B77DD4E503C6D6BBE2406BFBACE3932E855C661A9D2F5F7532E89F7 |
| 01 | daiwai | 6792BB97C2E387DDE29787BA563CFF44A79516C5446C2D7A09E476E687FC67E6 |
| 01 | damir00 | B165B1F36527A8D39DB48BB0838B77B886ECC7A309E191F37E39EA8A68FB6F86 |
| 02 | daiwai | C77A592244A3A79CBFC9BAA7A155F2C46050CCC6F72DEB1C18E5555E9E0F9D18 |
| 02 | damir00 | 725F2B07995A2DB322DE6AF63E18E389F65B43A6A39490872527089947700304 |
| 03 | damir00 | ECAA6DDD53DD97E991823F042DA704159C6AB1082F588D465F09533D52346FB2 |
| 04 | damir00 | 57F6C8B2CEFC2B5FA2662C615040F026BAD7FE20C8B9A05620095FCA4C57C60F |
| 05 | damir00 | 9FABD9953DE108D4A2E08EB8BA3EAABFA8585936E1ECAEA528EC8B4BA200AC1F |
If you are amongst the first three people to solve a task you can get your name in the hall of fame above. Simply open a pull request for this file and add your GitHub username and signature to the above table. Click here to fork and edit this page online.
The signature for each task is the SHA256 hash of <username>-<task_num>-<key>.
For example if the solution to task 05 is makarena then my signature would be
the hash of MKolman-05-makarena.
