CHALLENGE PUZZLE 04【Cypher編】

2024年3月22日

1 はじめに
2 暗号文
3 ヒント
4 解答への道
- 4.1 解答

はじめに

いつもブログをご覧いただきありがとうございます。

FIRE生活中のIPUSIRONです😀

暗号文

GOLDBUG

03 31 04 06 68 15 12 33 90 22 56 35

ヒント

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Beale.

Anagram.

解答への道

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1：暗号解読の方針を検討する

GOLDBUG

03 31 04 06 68 15 12 33 90 22 56 35

“GOLDBUG"を直訳すると「黄金虫」になります。

古典暗号の世界で「黄金虫」といえば、エドガー・アラン・ポーの小説『黄金虫』を連想します。

本のタイトルの下に数字の羅列があります。

そのため、書籍暗号による暗号文メッセージであると想像できます。

書籍暗号の暗号文は、通常「ページ数-行番号-単語の位置」や「ページ数-単語の位置-文字の位置」などという書式の羅列がよく使われます。

今回は単なる数字の羅列です。このことから。単語の位置だけを意味しており、その頭文字を取り出せばよさそうです。

※ヒントの"Beale"からビール暗号に気づけば、この方式はすぐに思いつくでしょう。

2：『黄金虫』の原文を用意する

The Project Gutenbergから"THE GOLD-BUG"の冒頭を引用します。

※暗号文メッセージに登場する数は2桁なので、冒頭だけを用意すれば十分です。

Many years ago, I contracted an intimacy with a Mr. William Legrand. He was of an ancient Huguenot family, and had once been wealthy; but a series of misfortunes had reduced him to want. To avoid the mortification consequent upon his disasters, he left New Orleans, the city of his forefathers, and took up his residence at Sullivan’s Island, near Charleston, South Carolina.

This Island is a very singular one. It consists of little else than the sea sand, and is about three miles long. Its breadth at no point exceeds a quarter of a mile. It is separated from the main land by a scarcely perceptible creek, oozing its way through a wilderness of reeds and slime, a favorite resort of the marsh hen. The vegetation, as might be supposed, is scant, or at least dwarfish. No trees of any magnitude are to be seen. Near the western extremity, where Fort Moultrie stands, and where are some miserable frame buildings, tenanted, during summer, by the fugitives from Charleston dust and fever, may be found, indeed, the bristly palmetto; but the whole island, with the exception of this western point, and a line of hard, white beach on the seacoast, is covered with a dense undergrowth of the sweet myrtle, so much prized by the horticulturists of England. The shrub here often attains the height of fifteen or twenty feet, and forms an almost impenetrable coppice, burthening the air with its fragrance.

The Project Gutenberg eBook of The Works of Edgar Allan Poe, Volume 1, by Edgar

The Project Gutenberg eBook of The Works of Edgar Allan Poe, Volume 1, by Edgar Allan Poe The Pr ...

https://www.gutenberg.org/cache/epub/2147/pg2147-images.html...

The Gold Bug by Edgar Allan Poe

The complete, unabridged text of The Gold Bug by Edgar Allan Poe, with vocabulary words and defi ...

https://poestories.com/read/goldbug

最初から100単語を抽出して、10単語ずつ並べると次のようになります。

 1 Many years ago I contracted an intimacy with a Mr
11 William Legrand He was of an ancient Huguenot family and
21 had once been wealthy but a series of misfortunes had
31 reduced him to want To avoid the mortification consequent upon
41 his disasters he left New Orleans the city of his
51 forefathers and took up his residence at Sullivan's Island near
61 Charleston South Carolina This Island is a very singular one
71 It consists of little else than the sea sand and
81 is about three miles long Its breadth at no point
91 exceeds a quarter of a mile It is separated from

3：暗号文を復号する

暗号文メッセージの数に対応する単語を抽出します。そして、その頭文字を特定します。

※ここでは暗号文メッセージの数を縦に並べました。

03 -> "ago"       -> 'A'
31 -> "reduced"   -> 'R'
04 -> "I"         -> 'I'
06 -> "an"        -> 'A'
68 -> "very"      -> 'V'
15 -> "of"        -> 'O'
12 -> "Legrand"   -> 'L'
33 -> "to"        -> 'T'
90 -> "point"     -> 'P'
22 -> "once"      -> 'O'
56 -> "residence" -> 'R'
35 -> "To"        -> 'T'

得られた文字を順序通り並べると、文字列"ARIAVOLTPORT"が得られます。

4：解答のキーワードを特定する

「アナグラム」というもう1つのヒントが残っています。

文字列"ARIAVOLTPORT"を並び替えてキーワードを特定します。

ポーの著作一覧を参考にしながら、合うキーワードを特定してください。