On the CD-ROM accompanying this book, you'll find a directory called message. Within it are two files: message.pgp and keys.asc. message.pgp is a small file, encrypted in 1024-bit PGP, that contains a hidden message. keys.asc is an ASCII file containing the PGP key generated for the hidden message. Your mission is to crack this hidden message by determining the passphrase used to encrypt it. This is not as difficult as it seems; it requires ingenuity rather than any particular cracking tool.
Following is a single line of clear text; your job is to determine the significance of that text. Having done so, you can crack the encrypted text. The public key used was email@example.com. The passphrase is composed of the significant strings you derive from the clear text. (These are not difficult to decode; their meanings are actually quite obvious if you apply yourself.) The clear text fields are separated by semicolons. That means the passphrase is a series of text strings. Examples of such text strings might be any of the following:
Each string will be in perfectly understandable English. Piece them together in order, and you will have the passphrase. This will serve as the private key necessary to decrypt the message.
Here is a powerful hint, and the only one I will give: The field separator (semicolon) represents one space, one dash, and one space. Thus, fields separated by semicolons in the following clear text represent phrases separated by a space, a dash, and a space. So if the hidden message was apples oranges pears, it would be written this way:
apples - oranges - pears
The message contained within that file is very serious. It relates a critical point about the Internet--one that even many security experts might have missed. That point will undoubtedly be a matter of some debate.
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