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Cryptography Challenge 7!
Link | by gendou on 2006-12-04 00:22:39 (edited 2010-09-14 16:31:44)
This thread is for discussion of the Gendou.com Cryptography Challenge #7.
Click the above link to view the challenge, get hints, and see the scoreboard.
Please do NOT post spoilers! You may post your ideas and strategies, but no actual answers, ciphers, or code.


Re: Cryptography Challenge 7!
Link | by Kit on 2006-12-04 06:49:56
Man... if it's number, it will be easier for me... But words? Never...

Loneliness have always been my friend...

Until the day I find you...


Re: Cryptography Challenge 7!
Link | by gendou on 2006-12-04 08:59:35 (edited 2006-12-04 10:05:34)
here is a hint: treat the letters in the words as numbers.

if you have given your best shot, but still need another hint, click here.


Re: Cryptography Challenge 7!
Link | by on 2006-12-04 10:24:42 (edited 2006-12-04 10:25:24)
gah im stump!i got the lyrics and the clue yet i cant still get it...


Re: Cryptography Challenge 7!
Link | by Huy on 2006-12-04 11:48:08 (edited 2006-12-04 12:28:39)
I got the first three lines or did I step into a trap?
It`s so random h could be h or u.
And what`s with this point in the fourth line?


Re: Cryptography Challenge 7!
Link | by gendou on 2006-12-04 16:20:01 (edited 2006-12-04 16:25:27)
the first 3 lines might be easily guessed. the last two lines are there to ensure that you have to truly crack the cipher in order to finish the challenge.

one big hint i will give is this:
decrypt(encrypt(input[x], key), key) = input[x] // you use the same key to encrypt as to decrypt
encrypt(input[a], key) != encrypt(input[b], key) // character position effects encryption/decription of the message



Re: Cryptography Challenge 7!
Link | by Huy on 2006-12-04 23:55:32
I don`t get your hints. ~_~


Re: Cryptography Challenge 7!
Link | by on 2006-12-05 00:24:04
wow!!! this is tough indeed (or am I just a complete ignorant?)

As for the lyrics, it should be a piece of cake for a Gendou.com member I know, XD.

Gendou-san: treat the letters as numbers... how?. Do you mean by numbering them as in the alphabet order?

I have no idea what the last hint means. -_-'... looks like a programming stuff.

Kei-kun's space for stupid comments: Everything changes... we all have to move on

Re: Cryptography Challenge 7!
Link | by gendou on 2006-12-05 00:27:08 (edited 2006-12-05 00:29:45)
yea. so, for example, a - a = 0 or c - a = b.
i did use programming syntax, because it is most familiar to me, but i translated into english in the comments.


Re: Cryptography Challenge 7!
Link | by Huy on 2006-12-05 12:12:32
Does the decryption depend on the position of the word?
Cause there are 2 "to" which are written the same way and at least 1 "to" which is different.


Re: Cryptography Challenge 7!
Link | by gendou on 2006-12-05 12:15:36 (edited 2006-12-05 18:52:52)
exactly. each character in the encoded message pairs up with a character in the key, which is used to find the decoded character.

Ok I am getting impatient. Please someone hurry up and win so I can post challenge #8! I have already finished writing it and I am excited :X


Re: Cryptography Challenge 7!
Link | by Maia on 2006-12-06 20:56:22
Hee. Sorry. I'm lost. Base conversions are much easier. :)

Re: Cryptography Challenge 7!
Link | by gendou on 2006-12-06 21:01:10
where did you get lost? did you find the lyrics?


Re: Cryptography Challenge 7!
Link | by on 2006-12-06 21:43:53 (edited 2006-12-06 21:46:46)
wow! you had to reduce the number of winners to just 3.

Anyway, I got the lyrics, the song, the translation, and I know that I have to treat the letters as numbers... but how can I operate them?... I mean, Gendou-san told me how but he just made the most simple operations... how about n - c or e - m ?

Is this the proof of how dumb I am?... T_T

Kei-kun's space for stupid comments: Everything changes... we all have to move on

Re: Cryptography Challenge 7!
Link | by yedijoda on 2006-12-06 22:53:31 (edited 2006-12-06 23:08:11)
Oooh! I just found this! How fun!

The key is inherent in the base text, right? So this is probably just a simple shift-and-arithmetic algorithm. Give me a bit of time on this--I'm having to do it by hand.

Just by way of a hint for the sake of time, how do you handle wraparounds?


Re: Cryptography Challenge 7!
Link | by EmptyMind on 2006-12-07 00:00:51
I can't believe I missed this post! Now I'm days behind! @_@

>,>; Did I just say that...?

Re: Cryptography Challenge 7!
Link | by gendou on 2006-12-07 00:27:00
the key is only letters and spaces. carriage returns reduce to spaces. punctuation is omitted.


Re: Cryptography Challenge 7!
Link | by yedijoda on 2006-12-07 14:47:59
Sorry. I meant numeric wraparounds.


Re: Cryptography Challenge 7!
Link | by gendou on 2006-12-07 17:58:13
oh, yes, overflow has to go somewhere otherwise information would not be decryptable.


Re: Cryptography Challenge 7!
Link | by Kit on 2006-12-07 23:12:26
-___-" I will pass... My brain isn't functioning at all...

Loneliness have always been my friend...

Until the day I find you...


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