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1*****
Looks like there may be a spot open for bonus points for cipher #4, the
easy version, so I am submitting my answer. No that's not a system clock
error, it really is 5:00 AM. I must be nuts. Sorry the text is so big. I
am cutting and pasting into UMBC e-mail and it doesn't work too well.
I used the frequency and n-gram analyzer as suggested. Then I used the
results to substitute letters. I figured the most frequent weren't
necessarily E, T, or A, and that it was probably a combo of many in the
middle frequencies. Guessing teh first word was "THE", lead to other
"THE"'s revealing themselves. I eventually knew I could use frequency
analysis on all but E, T, or A, so O, I, R, and S would be at the
top somewhere. More later in my write up.
Solution:
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2********
METHOD
used tool off of website to get the following, from there tried 'the'
as the first word of the cipher and went from there.
30 most frequently occuring numbers:
9023 83
20493 62
456 60
34082 54
23492 52
10375 51
5493 45
27331 41
7493 40
64901 39
2333910 33
432 32
4028 31
35132 31
30482 27
77712 27
31532 26
250111 26
4082 25
11052 25
64091 24
10333 23
4563 23
31533 22
3231 17
29310 15
30 15
732011 14
100573 12
44802 1
30 most frequently occuring digrams:
9023,7493 23
20493,34082 15
2333910,9023 12
5493,4028 11
34082,11052 11
9023,432 11
64091,5493 10
31532,5493 9
34082,27331 9
23492,23492 9
9023,456 9
432,20493 8
10333,27331 8
456,9023 7
9023,34082 7
23492,20493 7
23492,9023 7
77712,5493 7
30482,2333910 6
250111,9023 6
5493,64901 6
30,23492 6
5493,9023 6
456,20493 5
20493,29310 5
64901,456 5
35132,456 5
31533,34082 5
20493,23492 5
64901,27331 5
Used replace.pl from substitution cipher and created a bash script to work
with multiple substitution of letters.
replace.pl
#! /usr/bin/perl -w
# perl replace.pl cipherLetter plainLetter < cipherText [ > updatedCipher ]
$cipher = shift; # shift first arg into a var
$plain = shift; # shift second arg into a var
# were in array @ARGV
while ($line = <>) {
$line =~ s/$cipher /$plain /g;
print $line;
}
bash script
#!/bin/sh
echo -e "\n\n\n"
./replace.pl 31532 t < Cipher4.txt > tmp1
./replace.pl 5493 h < tmp1 > tmp2
./replace.pl 4028 e < tmp2 > tmp1
./replace.pl 9023 o < tmp1 > tmp2
./replace.pl 10375 s < tmp2 > tmp1
./replace.pl 77712 t < tmp1 > tmp2
./replace.pl 64091 t < tmp2 > tmp1
./replace.pl 7493 u < tmp1 > tmp2
./replace.pl 432 w < tmp2 > tmp1
./replace.pl 11052 g < tmp1 > tmp2
./replace.pl 2333910 y < tmp2 > tmp1
./replace.pl 31533 a < tmp1 > tmp2
./replace.pl 34082 n < tmp2 > tmp1
./replace.pl 27331 d < tmp1 > tmp2
./replace.pl 456 r < tmp2 > tmp1
./replace.pl 35132 e < tmp1 > tmp2
./replace.pl 23492 l < tmp2 > tmp1
./replace.pl 10333 e < tmp1 > tmp2
./replace.pl 30482 m < tmp2 > tmp1
./replace.pl 20493 i < tmp1 > tmp2
./replace.pl 732011 c < tmp2 > tmp1
./replace.pl 64901 e < tmp1 > tmp2
./replace.pl 4082 a < tmp2 > tmp1
./replace.pl 250111 f < tmp1 > tmp2
./replace.pl 29310 v < tmp2 > tmp1
./replace.pl 4563 a < tmp1 > tmp2
./replace.pl 100573 k < tmp2 > tmp1
./replace.pl 30 p < tmp1 > tmp2
./replace.pl 93 x < tmp2 > tmp1
./replace.pl 3231 b < tmp1 > tmp2
./replace.pl 44802 z < tmp2
echo -e "\n\n\n"
Chris Spiess
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3******
Subject: solution cipher#4 (difficult)
Hello Dr.
I had this one about just about solved before I had to
run off for classes today. Here it is.
I started with the initial guess that 412, 412 --> LL
Then I built "and". A = {23,34,98} N = {346, 404}
D = 68. Then my big break was to guess at LADY, so
y = 543. Then "you" became apparent O ={61, 87}
U = 76. this gave me "ould" which gave me "should".
>From there I was able to build "the", "our" and so
forth, lots of other words fell into place as well
along the way.
Tom Long
These things are better than crossword puzzles,
Thanks.
Here is the plain-text:
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