Civil War message decoded - any more information?

[wolf_meister]

This was one of the Internet “headlines” today and here’s a link to the story:

Discovery Hub - News & Technology

No it didn’t take over 140 years to break this but I was curious if there’s any detailed information about this.
Particularly, what is the original coded message? (All the images I’ve found don’t show enough resolution and the handwriting isn’t the greatest).
Since it is a Vigenère cipher what was the key word(s)?

[Crazyhorse]

There is a barely-readable picture here. They also link to a Vigenere cipher generator which they say they used to determine the key phrase was “Manchester Bluff”

[wolf_meister]

Thanks Crazyhorse

I searched for the most readable graphic and the best I could find is here
It’s 853 by 400 pixels and that guy’s penmanship sure doesn’t help.

[Olentzero]

This is weird. I can see the word patterns in the text when compared with the decoded message, but damned if the cipher doesn’t seem to change at random points. For instance, in line 1 cleartext GEN’L is ciphertext STAN, but in line 2 it is (as far as I can tell) RVSQ; then in line 6 it reverts to STA (cleartext GEN). And also in line 6 cleartext JOHNSTON, three different letters are represented by ciphertext L.

I dunno what them Rebs were smokin’, but damn if I don’t want some.

[Mr.Excellent]

@Olentzero

This is weird. I can see the word patterns in the text when compared with the decoded message, but damned if the cipher doesn’t seem to change at random points. For instance, in line 1 cleartext GEN’L is ciphertext STAN, but in line 2 it is (as far as I can tell) RVSQ; then in line 6 it reverts to STA (cleartext GEN). And also in line 6 cleartext JOHNSTON, three different letters are represented by ciphertext L.

I dunno what them Rebs were smokin’, but damn if I don’t want some.

Despair, mainly. At least in Vicksburg proper, they’d long since run out of everything else.

[Mk_VII]

"Gen’l Pemberton: You can expect no help from this side of the river. Let Gen’l Johnston know, if possible, when you can attack the same point on the enemy’s lines. Inform me also and I will endeavor to make a diversion. I have sent you some caps [percussion caps for the muskets]. I subjoin a despatch from General Johnston. "

http://www.leftcoastrebel.com/2010/12/pictures-civil-war-vignere-cipher-code.html

[dtilque]

@Olentzero

This is weird. I can see the word patterns in the text when compared with the decoded message, but damned if the cipher doesn’t seem to change at random points. For instance, in line 1 cleartext GEN’L is ciphertext STAN, but in line 2 it is (as far as I can tell) RVSQ; then in line 6 it reverts to STA (cleartext GEN). And also in line 6 cleartext JOHNSTON, three different letters are represented by ciphertext L.

Read up on the Vigenère cipher at the Wikipedia page and you’ll see why the same text is sometimes ciphered the same and sometimes not. The ones that are ciphered the same are a weakness that allows the code to be broken.

[sich_hinaufwinden]

@Crazyhorse

…a Vigenere cipher generator which they say they used to determine the key phrase was “Manchester Bluff”

I thought the following was interesting from the wiki page linked in the OP:

‘‘The Confederacy’s messages were far from secret and the Union regularly cracked their messages. Throughout the war, the Confederate leadership primarily relied upon three key phrases, “Manchester Bluff”, “Complete Victory” and, as the war came to a close, "Come Retribution.’’

[carnivorousplant]

@sich_hinaufwinden

Throughout the war, the Confederate leadership primarily relied upon three key phrases, “Manchester Bluff”, “Complete Victory” and, as the war came to a close, "Come Retribution.’’

That’s what they wanted the Yankees to believe.