[119251] in Cypherpunks
Re: Chalange to Tim May was: Re: Frequency Tables
daemon@ATHENA.MIT.EDU (Brad Kemp)
Wed Oct 20 12:18:52 1999
Message-Id: <3.0.3.32.19991020112900.04a55ac0@pop3.indusriver.com>
Date: Wed, 20 Oct 1999 11:29:00 -0400
To: ANTGamez@aol.com, cypherpunks@toad.com
From: Brad Kemp <kemp@indusriver.com>
Cc: coderpunks@toad.com, tcmay@got.net
In-Reply-To: <0.480f0f86.253e649b@aol.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Reply-To: Brad Kemp <kemp@indusriver.com>
At 08:19 PM 10/19/99 EDT, ANTGamez@aol.com wrote:
>Write your own code to encrypt a message, note: this code must be completely
>your own not something someone wrote or compiled a DLL for or any other such
>thing, I will do the same, then chose a publicly available book in English,
>type the first 3 pages in a plain windows text format, then encrypt it with
>your code and send the ciphertext to the list. then e-mail your code for
>your encryption to the list, I will do the same, the first one to gain the
>others plain text wins the challenge upon this happening the winner will
>supply to the list the passphrase for his message and the title of the book
>he chose it being confirmed that the supplied encryption code and passphrase
>produce a proper plaintext he will be declared the winner if said code and
>passphrase does not produce a proper copy of the plaintext, the winner will
>forfeit. You have been challenged, now it is a matter of honor.
#include <stdio.h>
main(argc, argv)
{
char * key = argv[2];
int len = atoi(argv[1]);
while(len--)
putchar(*key++ ^ getchar());
}
output:
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
It continues like this for some 3 pages.
You cannot break this code without the pass phrase, you cannot be sure of
anything you decipher is the correct plain text. In fact, I could, by changing
the key, make the plain text anything.
You need to do a bit of studying before you make such useless challenges.
I suggest Schneier's Applied Cryptography as a starting point.
Brad
--- -- --
Brad Kemp
Indus River Networks, Inc. BradKemp@indusriver.com
31 Nagog Park 978-266-8122
Acton, MA 01720 fax 978-266-8111
