The Beale Papers are a set of three ciphertexts, one of which allegedly states the location of a buried treasure of gold, silver and jewels. Comprising three ciphertexts, the first (unsolved) text describes the location, the second (solved) ciphertext the content of the treasure, and the third (unsolved) lists the names of the treasure's owners and their next of kin.

The story of the three ciphertexts originates from an 1885 pamphlet detailing treasure being buried by a man named Thomas J. Beale in a secret location in Bedford County, Virginia, in the 1820s. Beale entrusted a box containing the encrypted messages to a local innkeeper named Robert Morriss and then disappeared, never to be seen again. According to the story, the innkeeper opened the box 23 years later, and then decades after that gave the three encrypted ciphertexts to a friend before he died. The friend then spent the next twenty years of his life trying to decode the messages, and was able to solve only one of them which gave details of the treasure buried and the general location of the treasure. The unnamed friend then published all three ciphertexts in a pamphlet which was advertised for sale in the 1880s.

Beale's second cryptogram (the deciphered one).

Since the publication of the pamphlet, a number of attempts have been made to decode the two remaining ciphertexts and to locate the treasure, but all efforts have resulted in failure.

There are many arguments that the entire story is a hoax, including the 1980 article A Dissenting Opinion by cryptographer Jim Gillogly, and a 1982 scholarly analysis of the Papers and their related story by Joe Nickell, using historical records that cast doubt on the existence of Thomas J. Beale. Nickell also presents linguistic evidence demonstrating that the documents could not have been written at the time alleged (words such as stampeding, for instance, are of later vintage). His analysis of the writing style showed that Beale was almost certainly James B. Ward, whose 1885 pamphlet brought the Beale Papers to light. Nickell argues that the tale is thus a work of fiction.

Assignment

Your challenge is to decode a ciphertext contained in a text file. The ciphertext exists of a comma-separated sequence of natural numbers, where the commas might be preceded and followed by spaces. The sequence of natural numbers might be split over multiple lines in the text files, where splits never occur between digits of the same number.

39, 120, 11, 73, 22, 63, 73, 139, 53, 51, 69, 93, 112, 31, 63, 22, 42, 22, 63,
131, 112, 73, 22, 63, 8, 44, 60, 3, 151, 53, 117, 22, 112, 126, 22, 120, 83, 21,
43, 112, 73, 23, 22, 35, 56, 63

The key to decode the ciphertext are the words of a text contained in a text file. Herewith, we define a word as the longest possible sequence of letters. Each number from the ciphertext refers to the first letter at the corresponding position in the text, where the first word is at position 1, the second word at position 2, and so on. Your task:

Write a function numbers that takes the location of a text file containing a ciphertext. The function must return the list of integers that corresponds to the sequence of numbers in the given text file.
Write a function words that takes the location of a text file. The function must return the list of words contained in the given text file, with each word converted to lowercase.
Write a function decode that takes the locations of two text files: a file containing a ciphertext and a file containing a plaintext that forms the key to decode the ciphertext. The function must return a string that contains the decoded message, obtained by replacing each number from the ciphertext by the first letter of the word on the corresponding position in the plaintext. All letters of the decoded message returned by the function must be converted to lowercase.

Example

In the following interactive session we assume that the text files cipher.txt¹ en poem.txt² are located in the current directory.

        >>> numbers('cipher.txt')
[39, 120, 11, 73, 22, 63, 73, 139, 53, 51, 69, 93, 112, 31, 63, 22, 42, 22, 63, 131, 112, 73, 22, 63, 8, 44, 60, 3, 151, 53, 117, 22, 112, 126, 22, 120, 83, 21, 43, 112, 73, 23, 22, 35, 56, 63]

>>> words('poem.txt')
['as', 'i', 'have', 'gone', 'alone', 'in', 'there', 'and', 'with', 'my', 'treasures', 'bold', 'i', 'can', 'keep', 'my', 'secret', 'where', 'and', 'hint', 'of', 'riches', 'new', 'and', 'old', 'begin', 'it', 'where', 'warm', 'waters', 'halt', 'and', 'take', 'it', 'in', 'the', 'canyon', 'down', 'not', 'far', 'but', 'too', 'far', 'to', 'walk', 'put', 'in', 'below', 'the', 'home', 'of', 'brown', 'from', 'there', 'it', 's', 'no', 'place', 'for', 'the', 'meek', 'the', 'end', 'is', 'ever', 'drawing', 'nigh', 'there', 'll', 'be', 'no', 'paddle', 'up', 'your', 'creek', 'just', 'heavy', 'loads', 'and', 'water', 'high', 'if', 'you', 've', 'been', 'wise', 'and', 'found', 'the', 'blaze', 'look', 'quickly', 'down', 'your', 'quest', 'to', 'cease', 'but', 'tarry', 'scant', 'with', 'marvel', 'gaze', 'just', 'take', 'the', 'chest', 'and', 'go', 'in', 'peace', 'so', 'why', 'is', 'it', 'that', 'i', 'must', 'go', 'and', 'leave', 'my', 'trove', 'for', 'all', 'to', 'seek', 'the', 'answers', 'i', 'already', 'know', 'i', 've', 'done', 'it', 'tired', 'and', 'now', 'i', 'm', 'weak', 'so', 'hear', 'me', 'all', 'and', 'listen', 'good', 'your', 'effort', 'will', 'be', 'worth', 'the', 'cold', 'if', 'you', 'are', 'brave', 'and', 'in', 'the', 'wood', 'i', 'give', 'you', 'title', 'to', 'the', 'gold']

>>> decode('cipher.txt', 'poem.txt')
'natureunfoldshertreasureatthefirstrayofsunrise'

Assignment

Example

Epilogue