Cryptographer cracks secret coded message to Thomas Jefferson

200 years ago, a secret message was sent to President Jefferson

In 1801, President Thomas Jefferson received a taunting message written in secret code. Its author bragged the message would "defy the united ingenuity of the whole human race."

But more than 200 years later, the code has finally been cracked.

The letter's author was a mathematics professor in Pennsylvania -- and a friend of Thomas Jefferson -- named Robert Patterson. (Both men were members of the American Philosophical Society, a humanities group founded by Benjamin Franklin back in 1743.) "I presume the utter impossibility of decyphering will be readily acknowledged," Patterson bragged in December of 1801. And on Thursday the Wall Street Journal reported that no one in history has ever been proven to have solved the code. In fact, "Jefferson did believe the cipher was so inscrutable that he considered having the State Department use it, and passed it on to the ambassador to France, Robert Livingston."

Even while revealing how the letter was encoded, Mr. Patterson gleefully estimated that there were still "upwards of ninety millions of millions" of possible combinations. But 208 years later, a 36-year-old PhD in New Jersey -- now employed as a defense analysis cryptographer -- finally cracked it. In fact, cryptographer Lawren Smithline now says there were fewer than 100,000 calculations necessary for him to break the code, which he described as "tedious in the 19th century -- but doable."

Back in 1801, Patterson's first step had been simply writing in columns instead of rows. Here's how the first 12 words of the Declaration of Independence would look.

1. w c u s s r
2. h o m i n y 
3. e u a t e f
4. n r n b c o 
5. i s e e e r
6. n e v c s o
7. t o e o s n
8. h f n m a e
9. e h t e r p

Each column was 60 characters long. And this meant the rows -- reading left to right -- contained every 60th letter, a near nonsensical pattern. In the next step, those rows were scrambled.

3. e u a t e f
2. h o m i n y 
7. t o e o s n
1. w c u s s r
5. i s e e e r
4. n r n b c o 
8. h f n m a e
6. n e v c s o
9. e h t e r p

Every nine rows were scrambled in exactly the same order. For this example, the columns are only nine characters long, and if you stared at this (shorter) grid long enough, you might still recognize the first column as an anagram for "when in the " and the second column as "course of h--." But to make things more difficult, Patterson added random letters to the begining of each row. (And each row got a different amount of random letters!)

x q x e u a t e f
a p k l j h x r h o m i n y 
t t o e o s n
e l w c u s s r
p z k l r i i s e e e r
n r n b c o 
o p p o b h f n m a e
m l z k n e v c s o
e p r i s z x e h t e r p

To crack Patterson's code, readers would only need to use a separate key which would identify:

- Each row's original position.
- How many random letters were added to that row's beginning.

So for this example, the key would look something like this.

33
28
71
12
56
40
85
64
97

And if I'm understanding this correctly, even the linebreaks were removed -- though I'm guessing the length of each row was known.

x q x e u a t e f a p k l j h x r h o m i n y t t o e o s n e l w c u s s r p z k l r i i s e e e r n r n b c o o p p o b h f n m a e m l z k n e v c s o e p r i s z x e h t e r p

It'd then be easy to decipher the message if you had Patterson's key. ("33" means that to get the third row, you'd strike out the first three letters before counting out one row's length -- in this case, six letters.)

1. w c u s s r
2. h o m i n y 
3. e u a t e f
4. n r n b c o 
5. i s e e e r
6. n e v c s o
7. t o e o s n
8. h f n m a e
9. e h t e r p

But Patterson never provided the key, and the problem was still intriguing the New Jersey cryptographer, 200 years later. So he analyzed Thomas Jefferson's "State of the Union" addresses to estimate the frequency of every possible two-letter combination during Jefferson's time period. Then he ran the message through a complex computer algorithm which utilized "dynamic programming" to determine the best solutions. The computer crunched and churned, and after about a week of research, cryptographer Smithline had determined the numerical key.

13, 34, 57, 65, 22, 78, 49.

And what was the message that was encoded 200 years ago?

"In Congress, July Fourth, one thousand seven hundred and seventy six. A declaration by the Representatives of the United States of America in Congress assembled. When in the course of human events..."

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Two Centuries On, a Cryptologist Cracks a Presidential Code

Wall Street Journal

Fri Jul 3

7