# Impossible code challenge

1. Nov 26, 2013

### pixelpuffin

i wrote a script that codes phrases for me in c++ that should be impossible to solve
if anybody can solve the code i'll respond with the key and explain how it works

so here it is
05 08 13 52 19 55 89 44 33 77 10 82 88 84 23
65 46 52 57 95 37 93 18 11 29 40 69 34 97 87
21 52 17 33 86 20 37 96 37 33 70 03 73 24 95
25 97 99 73 19 45 95 85 79 41 20 03 05 08 21
21 34 55 89 44 33 23 10 87 97 84 81 65 34 11
57 68 25 93 21 11 29 40 69 09 60 87 55 52 17
37 86 24 95 96 37 33 70 03 73 97 52 25 34 99
73 33 45 21 24 79 41 20 03 05 08 37 21 34 55
89 44 33 52 10 87 97 84 81 65 95 11 57 68 25
93 95 11 29 40 69 09 21 87 21 52 17 20 86 19
28 96 37 33 70 03 73 37 11 25 97 99 73 21 45
23 64 79 41 20 03 05 08 34 21 34 55 89 44 33
95 10 87 97 84 81 65 21 11 57 68 25 93 82 11
29 40 69 09 19 87 20 52 17 37 86 19 42 96 37
33 70 03 73 24 11 25 19 99 73 34 45 55 37 79
41 20 03 05 08 64 21 34 55 89 44 33 85 10 87
97 84 81 65 42 11 57 68 25 93 37 11 29 40 69
09 19 87 64 52 17 78 86 37 64 96 37 33 70 03
73 28 37 25 33 99 73 95 45 95 97 79 41 20 03
05 08 37 21 34 55 89 44 33 64 10 87 97 84 81
65 37 11 57 68 25 93 11 11 29 40 69 09 37 87
64 52 17 37 86 97 21 96 37 33 70 03 73 11 37
25 55 99 73 37 45 64 19 79 41 20 03 05 08 28
21 34 55 89 44 33 37 10 87 97 84 81 65 11 11
57 68 25 93 28 11 29 40 69 09 60 87 19 52 17
11 86 34 95 96 37 33 70 03 73 97 19 25 95 99
73 76 45 19 55 79 41 20 03 05 08 37 21 34 55
89 44 33 52 10 87 97 84 81 65 95 11 57 68 25
93 19 11 29 40 69 09 78 87 19 52 17 95 86 37
64 96 37 33 70 03 73 42 95 25 97 99 73 19 45
95 85 79 41 20 03 05 08 21 21 34 55 89 44 33
23 10 87 97 84 81 65 64 11 57 68 25 93 37 11
29 40 69 09 19 87 38 52 17 21 86 23 95 96 37
33 70 03 73 95 21 25 20 99 73 42 45 21 11 57

i will post hints until i have run out once per day

Last edited: Nov 26, 2013
2. Nov 26, 2013

### AlephZero

Most of what you posted is just repetitions of the two low-order digits of a Fibonacci sequence, wtih a few entries zeroed out.
Code (Text):

05 08 13 00 34 55 89 44 00 77 10 87 97 84 81 65 46 11 57 68 25 00 18 11 29 40 69
03 05 08 13 21 34 55 89 00 33 77 10 87 97 84 81 65 00 11 57 68 25 93 18 11 29 40 69
... then 33 copies of
03 05 08 13 21 00 00 89 44 33 77 00 87 97 84 81 65 46 11 57 68 25 93 18 11 29 40 00
... then
03 05 08 13 21 00 00 89 44 33 77

IF the only "information" is the location of the six 00's, I suppose the phrase is only 6 characters long.
Or maybe your code needs more debugging

3. Nov 26, 2013

### Student100

The quick brown fox jumps over the lazy dog.

4. Nov 26, 2013

### Staff: Mentor

Good cryptography:

1. code is not secret
2. the code undergoes extensive scrutiny by the crypto community.
3. Agencies after several years of deciding the future usefulness, may assign the cryptographic algorithm to a list like the one NIST maintains.

You are doing this backwards, IMO. I know it's fun to do this. But you may want to consider something like Bruce Schneier's 'Applied Cryptography.'
https://www.amazon.com/Applied-Cryp...8&qid=1385508138&sr=1-4&keywords=cryptography

There is a lot of code to play with in there. If I remember right it has a version of what later became blowfish - think it was called 'twofish'. The TEA algorithm is also fun. I think the book is now on the order of $8-$10 US.
College libraries also have it.

5. Nov 26, 2013

### pixelpuffin

sorry i posted the old buggy output
i updated the original post with the correct output

6. Nov 26, 2013

### jhae2.718

If this is something you're actually considering to use as a cryptosystem, consider the following:

Kerckhoff's Principle states that a cryptosystem's security should depend only on the secrecy of the key. This can be stated also as "The enemy knows the system." (This latter formulation is from Claude Shannon.)

7. Nov 26, 2013

### jhae2.718

Applied Cryptography is very good if a bit outdated. Schneier has a newer cryptography book written with Neils Ferguson and Tadayoshi Kohno called Cryptography Engineering that is more up-to-date and focuses more on the implementation issues of cryptosystems, which is the weak link in the security chain, as our current algorithms are quite good, but their implementations are abysmal.

Applied Cryptography has the source to Blowfish. Twofish is a later algorithm that was a finalist in NIST's AES contest. Schneier has a lot of information on his website, including source code to Blowfish, Twofish, Solitaire (which should be familiar to readers of Neal Stephenson's Cryptonomicon, Threefish, and other algorithms in a variety of languages.

8. Nov 26, 2013

### Student100

Here are you frequency and sequences:
2 letter sequences

37 => 49
21 => 35
73 => 32
94 => 29
97 => 27
33 => 26
11 => 24
79 => 23
12 => 23
59 => 23
52 => 22
08 => 21
95 => 21
45 => 19
03 => 18
25 => 18
34 => 17
00 => 17
87 => 17
19 => 16
78 => 15
82 => 14
55 => 13
76 => 13
41 => 13
57 => 13
58 => 12
63 => 12
20 => 12
29 => 11
81 => 11
93 => 11
72 => 11
15 => 11
96 => 11
64 => 10
05 => 10
69 => 10
65 => 10
13 => 10
44 => 10
89 => 10
86 => 10
71 => 10
70 => 9
17 => 9
09 => 9
99 => 9
40 => 9
43 => 9
50 => 9
84 => 9
10 => 9
06 => 9
90 => 8
39 => 8
31 => 8
30 => 8
48 => 8
68 => 8
16 => 8
32 => 8
51 => 8
49 => 7
42 => 7
53 => 6
83 => 5
23 => 5
28 => 5
24 => 5
91 => 4
77 => 4
18 => 4
38 => 4
85 => 4
62 => 3
98 => 3
54 => 3
36 => 3
88 => 3
35 => 3
92 => 3
3 letter sequences

373 => 18
003 => 17
521 => 16
337 => 15
733 => 14
259 => 12
112 => 11
637 => 11
978 => 10
037 => 10
087 => 10
115 => 9
069 => 9
973 => 9
157 => 9
455 => 9
370 => 9
700 => 9
963 => 9
406 => 9
997 => 9
217 => 9
294 => 9
894 => 9
944 => 9
443 => 9
589 => 9
558 => 9
508 => 9
050 => 9
940 => 9
433 => 9
108 => 9
345 => 9
129 => 9
879 => 8
200 => 8
134 => 8
030 => 8
305 => 8
213 => 8
165 => 8
825 => 8
682 => 8
593 => 8
690 => 8
909 => 8
768 => 8
576 => 8
848 => 8
784 => 8
481 => 8
816 => 8
412 => 8
797 => 8
120 => 8
941 => 8
794 => 8
721 => 7
595 => 6
111 => 5
952 => 5
372 => 5
452 => 5
395 => 5
764 => 5
711 => 5
371 => 5
959 => 5
211 => 5
082 => 4
737 => 4
083 => 4
951 => 4
511 => 4
837 => 4
579 => 4
739 => 4
378 => 4
195 => 4
597 => 4
173 => 4
212 => 4
732 => 4
979 => 4
821 => 4
091 => 3
459 => 3
421 => 3
125 => 3
342 => 3
198 => 3
376 => 3
641 => 3
719 => 3
863 => 3
645 => 3
987 => 3
958 => 3
919 => 3
731 => 3
411 => 3
352 => 3
872 => 3
349 => 3
525 => 3
931 => 3
555 => 3
862 => 3
537 => 3
319 => 3
799 => 3
495 => 3
786 => 3
596 => 3
194 => 3
4 letter sequences

7337 => 11
3733 => 10
3370 => 9
6373 => 9
9637 => 9
3700 => 9
0037 => 9
0508 => 9
1157 => 9
9973 => 9
0373 => 9
5217 => 9
7003 => 9
4433 => 9
9443 => 9
5894 => 9
5589 => 9
1129 => 9
8944 => 9
1294 => 9
9406 => 9
4069 => 9
2940 => 9
8481 => 8
7848 => 8
9784 => 8
8797 => 8
6909 => 8
4816 => 8
1087 => 8
0879 => 8
7978 => 8
7682 => 8
8259 => 8
2593 => 8
3455 => 8
6825 => 8
0690 => 8
1576 => 8
5768 => 8
8165 => 8
4558 => 8
1200 => 8
4120 => 8
7941 => 8
1345 => 8
2003 => 8
9412 => 8
0030 => 8
3050 => 8
0305 => 8
2134 => 8
2173 => 4
5083 => 4
3371 => 4
8372 => 4
4521 => 4
3711 => 4
0837 => 3
9511 => 3
7213 => 3
3721 => 3
9198 => 3
7645 => 3
3764 => 3
9521 => 3
1987 => 3
0919 => 3
1115 => 3
9091 => 3
7112 => 3
7378 => 3
9799 => 3
5979 => 3
2597 => 3
7997 => 3
4595 => 3
5082 => 3
5794 => 3
3732 => 3
2111 => 3
5963 => 3
3739 => 3
9596 => 3
3786 => 3
3521 => 3
1737 => 3
9733 => 3
5 letter sequences

37337 => 10
73370 => 9
63733 => 9
33700 => 9
37003 => 9
55894 => 9
70037 => 9
96373 => 9
00373 => 9
94433 => 9
89443 => 9
11294 => 9
58944 => 9
94069 => 9
29406 => 9
12940 => 9
97848 => 8
84816 => 8
79784 => 8
78481 => 8
08797 => 8
48165 => 8
10879 => 8
87978 => 8
76825 => 8
82593 => 8
40690 => 8
34558 => 8
68259 => 8
06909 => 8
15768 => 8
57682 => 8
11576 => 8
45589 => 8
12003 => 8
94120 => 8
79412 => 8
13455 => 8
20030 => 8
41200 => 8
30508 => 8
21345 => 8
03050 => 8
00305 => 8
05083 => 4
52173 => 4
72134 => 3
37213 => 3
83721 => 3
08372 => 3
50837 => 3
09198 => 3
90919 => 3
91987 => 3
69091 => 3
11157 => 3
37112 => 3
33711 => 3
21737 => 3
97997 => 3
59799 => 3
79973 => 3
57941 => 3
05082 => 3
25979 => 3
03732 => 3
59637 => 3
03739 => 3
95963 => 3
73786 => 3
17378 => 3
99733 => 3
6 letter sequences

337003 => 9
373370 => 9
370037 => 9
700373 => 9
558944 => 9
637337 => 9
733700 => 9
963733 => 9
589443 => 9
894433 => 9
112940 => 9
294069 => 9
129406 => 9
978481 => 8
784816 => 8
797848 => 8
455894 => 8
848165 => 8
087978 => 8
879784 => 8
406909 => 8
940690 => 8
345589 => 8
682593 => 8
768259 => 8
157682 => 8
576825 => 8
115768 => 8
108797 => 8
120030 => 8
941200 => 8
794120 => 8
134558 => 8
200305 => 8
412003 => 8
030508 => 8
213455 => 8
003050 => 8
305083 => 4
372134 => 3
837213 => 3
083721 => 3
508372 => 3
050837 => 3
909198 => 3
091987 => 3
690919 => 3
069091 => 3
337112 => 3
721345 => 3
217378 => 3
597997 => 3
979973 => 3
579412 => 3
305082 => 3
259799 => 3
003732 => 3
596373 => 3
959637 => 3
173786 => 3
521737 => 3
003739 => 3

9. Nov 26, 2013

### AlephZero

Probably irrelevant, unless you ignore the Fibonacci padding that is still there.

First 3 lines:
Code (Text):

code 05 08 13 [COLOR="Red"]52 19[/COLOR] 55 89 44 33 77 10 [COLOR="red"]82 88[/COLOR] 84 [COLOR="red"]23[/COLOR]
Fib  05 08 13 21 34 55 89 44 33 77 10 87 97 84 81

Code 65 46 [COLOR="red"]52[/COLOR] 57 [COLOR="red"]95 37[/COLOR] 93 18 11 29 40 69 [COLOR="red"]34 97[/COLOR] 87
Fib  65 46 11 57 68 25 93 18 11 29 40 69 09 78 87

Code [COLOR="red"]21[/COLOR] 52 17 [COLOR="red"]33[/COLOR] 86 [COLOR="red"]20 37[/COLOR] 96 37 33 70 03 73 [COLOR="red"]24 95[/COLOR]
Fib  65 52 17 69 86 55 41 96 37 33 70 03 73 76 49

... etc

10. Nov 27, 2013

True.