*bump* Noting how much people are struggling with Challenge 3 and with jonbush's agreement, we have decided to release one additional hint at this time: Challenges 1 to 3 have all used ciphers that can be found in the "Classical Cryptography" template on Wikipedia. A special congratulations to the >=2 contestants who solved the challenge before this hint!

*bump* Contest #15, Challenge #3 hint time:
You wouldn't put calculators on your salad

c4ooo: Please try to avoid posting hints about the cipher. Note that the rules posted for the last challenge specify that things like constants should be changeable in the source.

For the past two Tuesdays, we have announced increasingly difficult challenges as part of Cemetech Contest #15: Crypto Golfing. This five-part contest tasks programmers with solving cryptography puzzles, then creating programs that can decode messages in the cipher used for each challenge. We received an overwhelming number of entries written in many different calculator and computer languages for Challenges 1 and 2, although the field has started to thin. Since another Tuesday is upon us, Challenge 3 of Cemetech Contest #15 is here! If you haven't started entering the contest yet or if you haven't completed one of the existing challenges, you still have time, and the only thing you'll lose is the (up to) 5 bonus points you get by submitting your solutions quickly. Challenge 3 is the last pure-text cipher, and if you're still stuck with it on Friday, we'll be publishing an extra hint on Friday afternoon at 5pm, Eastern Time.

Challenge 3: OEEJCYKL WK AU LTMY L WXOJWN

Good luck! To repeat the incentive, besides prestige and glory: a TI-Nspire CX and a TI-84 Plus C Silver Edition await the top two contestants.

Quote from: jonbushIf you haven't figured out Challenge 2 yet, here's a hint:

%26

I'm Kerm Martian and I approve of this message. Good luck, everyone. I notice we haven't quite gotten as many entries as for the first challenge, so I hope everyone who is stuck on this one (or forgot to enter so far this week) will redouble their efforts.

The earlier you send them, the higher your score, but you can send all of the solutions together on the very last day of the contest if you so desire.

I'm happy to announce that another Tuesday is upon us, so Challenge 2 of Cemetech Contest #15 is also here! If you haven't completed Challenge 1 yet, you still have time, and the only thing you'll lose is the (up to) 5 bonus points you get by submitting your solutions quickly. Challenge 2 adds a few additional rules that we learned from seeing how people worked with Challenge 1:

• For Challenges 2 and 3, TI-BASIC, Axe, and Assembly programs should take the ciphertext in Ans and return the decoded plaintext in Ans as well.
  
• For Challenges 2 and 3, computer programs should take input from stdin and return output to stdout.
  
• If there are any constants or keys that affect how a particular cipher works (for example, the offset in a Caesar cipher), these should be defined in a modifiable way in the source, so that someone with the source code could change those constants without needing to modify anything else in the program.

Challenge 2: VPUOUGHUVYUOOSIUWOPSTTEPMRWNSEOBHMYGUYUVUGP

Good luck!

Good luck to all! And thanks for front-paging this.

Quote from: Juju on December 16, 2015, 02:23:26 AM
Hmm, by decoding, I assume it's a symetrical algorithm and you don't have to crack any keys? Also, I assume the result of the challenge is something meaningful in English?

Correct on both counts.

Quote from: Juju on December 16, 2015, 02:23:26 AM

Quote from: KermMartian on December 16, 2015, 12:14:39 AM
Submit entries by emailing them, in a zip file, to contest at this domain name.

Sending your entries at this actual domain name is probably not a good idea (I know, you meant Cemetech's domain name )

Good catch.

DJ_O: Yep! It has the additional challenge that you have to figure out what the algorithm actually is before you can write a minimal solver for it.
Juju, Alexgt: Best of luck!

Last month, we resurrected Cemetech programming contests with Cemetech Contest #14: TI-BASIC Connect 4 AI Challenge. In that short contest, designed by Cemetech members jonbush and earthnite, entrants were tasked with writing an AI to play Connect 4 in pure TI-BASIC. We congratulate JWinslow23 for winning that contest, and are happy to announce a longer, more elaborate contest. Cemetech Contest #15 is entitled Crypto Golfing, and is a multi-part contest. Starting today, and continuing every Tuesday until January 12th, we will release encrypted data with possible hints for a new challenge. Your mission, should you choose to accept it, is to create a program to decode each piece of encrypted data, be it a string, a number, an image, or something else, in as few bytes as possible. The top two overall winners will win a TI-84 Plus C Silver Edition and a TI-Nspire CX (with the first place winner getting first choice).

As in previous Cemetech contests, we'll have a number of categories; the sizes of entries from each category will be weighted at the discretion of the judging panel.

• TI-83 Plus/TI-84 Plus TI-BASIC, ASM, C, or Axe: Programs in any of these languages for any calculator with "TI-83 Plus" or "TI-84 Plus" in its name will be accepted, including the TI-84 Plus C Silver Edition and TI-84 Plus CE. Hybrid TI-BASIC and z80 ASM programs must use only the libraries available in Doors CS or Doors CSE, to make grading easier.
  
• TI-Nspire CX and HP Prime: Lua entries for the TI-Nspire CX and CX CAS as well as PPL programs for the HP Prime will be accepted.
  
• Computers: Java, Javascript, C++, Rust, Haskell, and Python: For those who focus on computer programming these days, computer programming solutions will be accepted in the languages listed. Want to write in another language? Let us know what that language is in the attached Cemetech topic, and we'll consider it.

The usual rules apply:

• Contestants may not release any code or binaries before the end of the contest, including asking for programming help publicly or privately. Violators will be disqualified. Projects that have already been released in any form (excluding a contest project topic) already are not eligible for the contest.
  
• The contest will run until January 19th, 2016, at 11:59:59pm Eastern Time. No late entries will be accepted. Entries to any of the five challenges will be accepted up until this deadline. The earlier you submit each challenge's solution, the higher your score!
  
• All contestants must maintain a topic in the Contests subforum on Cemetech, including a first post that mentions the programming language(s) you'll be using. You can also post the size of your entries and when you complete them. Do not post algorithmic solutions, code, or hints.
  
• Submit entries by emailing them, in a zip file, to contest at the Cemetech domain name. Be sure to provide your Cemetech username in the subject or body of the email so we know who you are! Each Cemetech member can submit a single entry in one or more of the accepted language + platform combinations.
  
• Judging will be performed by a team picked from among the Cemetech administrators and members; all judges are disqualified from entering the contest. Results will be posted no later than ten days after the end of the contest.
  
• Algorithmic grading will be performed, based on the size of each entry's source code (or for assembly, assembled binaries) and how early the entry was submitted. Speed will not be graded.
  
• As with the Contests #12 and #13, we are very proud to offer two brand-new calculators as prizes. The grand prize winner will be awarded one TI-84 Plus C Silver Edition or one TI-Nspire CX, as chosen by the winner. The second-place winner will receive the remaining calculator. Additional Cemetech swag may be added to the prizes at the Cemetech staff's discretion. All participants will earn Cemetech flair in the form of signature bars and respect.

So what are you waiting for? Get coding, solve Challenge 1, push yourself to learn something new in the process, and win some calculators!

Challenge 1: GSVHVXIVGNVHHZTVRHLOWDRAZIW

More Information
Contest #15 Rules



Both of the two remaining of these six generously-donated calculators will be awarded as prizes. A special thanks to our anonymous donor for making this contest possible!

prgmA is 22 bytes in RAM, the launcher (prgmDOORSCE) is 267 bytes in RAM, and AppVar DCEMAIN (which contains the shell itself) is 20,651 bytes. I wouldn't be surprised if it grows to as much as 38K once xLIBCE and Celtic 2 CE get stuffed in there.

Since the release of TI's thin, light, ez80-powered TI-84 Plus CE graphing calculator, I have received countless YouTube comments, Cemetech PMs and posts, and emails about when Doors CS / Doors CSE would be available for the new calculator. Stumbling blocks including technical limitations related to the new calculator and my own lack of free time had forced me to say that I wasn't sure when or if a version of Doors CS/CSE would be available for the TI-84 Plus CE. For a long time, I hoped that an App key might become available from TI so that there might be a TI-84 Plus CE App version of Doors CS/CSE. It appears that that's not forthcoming, so in the meantime, I've been working on a port of Doors CS/CSE as a program, to be called Doors CE. Like the much-celebrated Cesium from Cemetech Expert MateoConLechuga, the new Doors CE is visible in the [PRGM] menu, and can be started by running a prgmA that Doors CE creates when you install it.

Since the beginning of October, I have been documenting my progress on putting together a Doors CE port for the TI-84 Plus CE. The following features have been completed, delta a little debugging:

• Launcher: Doors CE creates a special launcher when it is installed and archives its bulk as an AppVar to leave RAM for user programs. The launcher also switches between Doors CE and assembly programs when the user executes a program.
  
• Desktop: Doors CE can display BASIC and Assembly programs on its desktop, list an arbitrary number of programs, and scroll. Locked, archived, and hidden programs are correctly annotated as such. Folders can be created, and files can be moved between folders. Programs can be created, renamed, duplicated, deleted, and even edited. The clock works.
  
• Doors CE and Options Menus: The Doors CE menu ("start" menu) works correctly, and each of its sub-menus functions. The Options menu works, and most of the options in Options do what they're supposed to.
  
• Executing nostub BASIC programs: BASIC programs can be executed from the Doors CE desktop from RAM or Archive.
  
• Executing nostub ASM programs: ASM programs can be executed from the Doors CE desktop from RAM or Archive. Writeback is correctly performed.

There are a few features that still need to be added, and they're big ones:

• HomeRun: The HomeRun feature that lets programs be executed from the homescreen, regardless of whether they're BASIC or ASM, Archived or in RAM, or require libraries is incomplete (but nearly done). BASIC programs currently work; ASM programs do not.
  
• xLIBCE: The venerable Patrick "tr1p1ea" Prendergast is working hard to port xLIBC to the TI-84 Plus CE for inclusion in Doors CE. Since he has a busy job and a young family, I appreciate his willingness to work on xLIBCE in his minuscule free time.
  
• Celtic 2 CE: I will be porting the Celtic 2 CSE libraries from Doors CSE. With the permission of authors like MateoConLechuga, I may add additional functions, including ToString.
  
• ASM/C libraries: MateoConLechuga has also strongly hinted that he is completing tools that will make it easy to use ASM and C libraries in programs without explicit shell support. Doors CE will be leveraging this time- and effort-saving breakthrough from Mateo.

If you still need to get psyched about Doors CE, enjoy the video below. Although I don't have a concrete release date for Doors CE, I do plan to get it out in the early part of 2016. I'd be happy to field suggestions and answer questions in the attached topic or in the Doors CE 9 Development thread, where development updates will continue to be posted.

Quote from: Streetwalrus on December 07, 2015, 10:57:42 PM
KermM, friendly reminder that [you have no power here]

If you have something interesting to say, say it. All your baseless accusations, as implicit as they are, hold no value though. Either post proof of what you're saying or don't post at all.

That said it looks to me like most of the community is under attack, even our own logs show that the suspicious IPs are trying to access CW with the passwords they stole, as well as ticalc.org and Revsoft.

Don't worry, I'm not blaming CodeWalrus as a whole; I respect almost all of you a great deal, I just wish you hadn't felt that the community needed to be subdivided further (@aeTIos too). Point taken, though; I certainly have no power here, and I wouldn't want anyone to think I was being mean. *doffs hat* A good day to you, ladies and gents.

Quote from: DJ Omnimaga on December 07, 2015, 10:11:27 PMCould it be Islamic State in response to our Paris attack thread? They don't like free speech so...

What? That seems like a stretch, especially since the Omnimaga staff and I determined that it's a community member performing these attacks (and they've been focused on a few select portions of the community).

Quote from: StreetwalrusThe attacker could have prepared his attack before you guys updated by setting up a backdoor. Did they leave anything behind on the server or did they kill it all ?

The attacker had an administrator's password, and did not use any backdoors or brute force.

Sorry to hear that you guys were also hit a day later by this attacker. I hope as a community we can all get to the bottom of who feels so destructively towards us.