Secret algorithm (KPTA 2).


Description:

This encryption method is based on using an algorithm that doesn't require a key. The strength of this cryptosystem resides with the secrecy of the algorithm, not with the key.

That is a bad practise because once you know the method you can decrypt any text you want.
Your aim is to analyse some texts with their corresponding cipher texts and determine the algorithm. Once you know the algorithm decrypt the final text.

Examples:

Text #1:

  The orbits of the planets are ellipses, with the Sun at one focus of the ellipse.
Encrypted Text #1:
  ----------------------------------------------------------------------
  | b0 d3 a0 a1 e2 a7 87 a3 8f 9f d1 c7 25 8a 64 a9  |   ‡�Ÿ%Šd  |
  | 7c e7 51 ec 51 d8 4f c6 bd 8e f1 aa fb e4 cb f2  |  |QQOƽŽ  |
  | fe fc fa 08 e1 05 8b 06 c9 63 d9 68 ac 37 a5 c5  |  ..‹.ch7  |
  | f5 bd ee b1 ad 8b ad d0 d7 ca d1 78 8a 7a b3 73  |  ‹xŠzs  |
  | c0 2b 92 15 d9 5a 30 58 60 26 64 31 1c 23 0a 0a  |  +’.Z0X`&d1.#..  |
  | 54                                               |  T                 |
  ----------------------------------------------------------------------
Decrypted Text #1:
  ----------------------------------------------------------------------
  | 54 68 65 20 6f 72 62 69 74 73 20 6f 66 20 74 68  |  The orbits of th  |
  | 65 20 70 6c 61 6e 65 74 73 20 61 72 65 20 65 6c  |  e planets are el  |
  | 6c 69 70 73 65 73 2c 20 77 69 74 68 20 74 68 65  |  lipses, with the  |
  | 20 53 75 6e 20 61 74 20 6f 6e 65 20 66 6f 63 75  |   Sun at one focu  |
  | 73 20 6f 66 20 74 68 65 20 65 6c 6c 69 70 73 65  |  s of the ellipse  |
  | 2e                                               |  .                 |
  ----------------------------------------------------------------------

Text #2:

  The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse.
Encrypted Text #2:
  ----------------------------------------------------------------------
  | e3 80 f3 f2 b2 ec c0 e8 90 99 98 88 62 84 70 b2  |  €�™˜ˆb„p  |
  | 22 ed 43 f7 0b 9c 02 9e f8 8e e4 ed ad fd 97 b6  |  "C.œ.žŽ—  |
  | be b0 e6 34 cd 34 b6 68 a7 01 aa 03 94 5b ce be  |  44h..”[ξ  |
  | da e1 a2 e2 ab 8d b3 ce c7 c6 dd 35 d2 6d ae 75  |  �5mu  |
  | 95 3b 9c 08 85 1e 3c 45 34 7a 31 7b 1f 31 18 5d  |  •;œ.….<E4z1{.1.]  |
  | 59 4a a9 18 f4 3f ec 3f 92 35 cb 56 d0 4e 32 42  |  YJ.??’5VN2B  |
  | 0e 56 40 60 5e 66 71 72 6e cd 37 c6 07 88 57 fe  |  .V@`^fqrn7.ˆW  |
  | 42 f0 66 e4 7d 54                                |  Bf}T            |
  ----------------------------------------------------------------------
Decrypted Text #2:
  ----------------------------------------------------------------------
  | 54 68 65 20 6c 69 6e 65 20 6a 6f 69 6e 69 6e 67  |  The line joining  |
  | 20 74 68 65 20 70 6c 61 6e 65 74 20 74 6f 20 74  |   the planet to t  |
  | 68 65 20 53 75 6e 20 73 77 65 65 70 73 20 6f 75  |  he Sun sweeps ou  |
  | 74 20 65 71 75 61 6c 20 61 72 65 61 73 20 69 6e  |  t equal areas in  |
  | 20 65 71 75 61 6c 20 74 69 6d 65 73 20 61 73 20  |   equal times as   |
  | 74 68 65 20 70 6c 61 6e 65 74 20 74 72 61 76 65  |  the planet trave  |
  | 6c 73 20 61 72 6f 75 6e 64 20 74 68 65 20 65 6c  |  ls around the el  |
  | 6c 69 70 73 65 2e                                |  lipse.            |
  ----------------------------------------------------------------------

Text #3:

  The ratio of the squares of the revolutionary periods for two planets is equal to the ratio of the cubes of their semimajor axes.
Encrypted Text #3:
  ----------------------------------------------------------------------
  | 5f 3c 4f 4e 10 46 70 54 63 20 21 3e 9a 61 93 53  |  _<ON.FpTc !>ša“S  |
  | c3 0b bc 18 a5 30 a7 29 01 7d 05 0c 4c 1b 34 41  |  ..0).}..L.4A  |
  | 53 5d 5d b3 53 b1 67 a3 74 d9 76 dd 40 8f 05 65  |  S]]Sgtv@�.e  |
  | 07 75 3c 69 26 41 75 47 5d 0e 04 fa 01 be 64 bd  |  .u<i&AuG]...d  |
  | 1c b9 0a 9f 00 d7 bc c2 fa bc e3 af 8a a9 d3 c2  |  ..Ÿ.׼Š  |
  | dd 86 74 8d 74 f3 33 ef 53 e9 58 91 0a 93 b9 d8  |  †t�t3SX‘.“  |
  | 90 de c8 ea d3 e6 e1 ff a7 4b a3 1a ca 0d d2 7e  |  �K..~  |
  | dc 27 b2 26 b7 d9 a6 da 98 c4 88 e1 d4 f3 fc fa  |  '&٦˜ˆ  |
  | 54                                               |  T                 |
  ----------------------------------------------------------------------
Decrypted Text #3:
  ----------------------------------------------------------------------
  | 54 68 65 20 72 61 74 69 6f 20 6f 66 20 74 68 65  |  The ratio of the  |
  | 20 73 71 75 61 72 65 73 20 6f 66 20 74 68 65 20  |   squares of the   |
  | 72 65 76 6f 6c 75 74 69 6f 6e 61 72 79 20 70 65  |  revolutionary pe  |
  | 72 69 6f 64 73 20 66 6f 72 20 74 77 6f 20 70 6c  |  riods for two pl  |
  | 61 6e 65 74 73 20 69 73 20 65 71 75 61 6c 20 74  |  anets is equal t  |
  | 6f 20 74 68 65 20 72 61 74 69 6f 20 6f 66 20 74  |  o the ratio of t  |
  | 68 65 20 63 75 62 65 73 20 6f 66 20 74 68 65 69  |  he cubes of thei  |
  | 72 20 73 65 6d 69 6d 61 6a 6f 72 20 61 78 65 73  |  r semimajor axes  |
  | 2e                                               |  .                 |
  ----------------------------------------------------------------------

Challenge:

Decrypt this:

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  | db f0 96 c5 8c dd fa c5 bd aa ac b0 14 cb 25 ef  |  –ŒŽ.%  |
  | 33 ed 46 f6 43 c7 15 bd db a1 c9 85 c3 8f a0 d5  |  3FC.ۡ…�   |
  | c2 c1 d2 21 c8 65 e7 1e ce 68 e3 5b cd 56 c4 88  |  !e.h[Vˆ  |
  | eb b1 e3 86 d2 f0 e1 d9 df d8 c3 38 e3 1a e4 39  |  †8.9  |
  | 9c 02 ba 32 a8 3a 4a 34 49                       |  œ.2:J4I         |
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