unforum

[RainbowAli]

Also:

http://memory.loc.gov/mss/mgw/mgw4/094/0000/0025.gif

is needed for some of the words if this coding is used.
There are other pages floating around that contain single letter substitutions and continuation of the code, but I think this is the only other one we may need to check at the moment.

[Ueno]

using code i got this (and using hebrew converted to number code before)

foreign light about improvement
health .... many imagine
do fulfill obligation by factor
defence question .....
gain and
and adjourn ....
innocent .....

4 blanks where can't read words on code sheet
doesnt make much sense to me
any ideas?

[doublecross]

Doesn't look like the right code to me. I think the first word is 'fortune', by the way.

The other word-segment list one starts with ua-better-car... which is even less likely to be right.

It is 'just' a case of finding the right source to index the numbers into. Hale could well be a clue. XY=600 may also be a clue but it could just be telling us to translate the Hebrew letters to numbers.

[Belogroak]

I really believe the following have to be clues to solving this

1) the equations on the white card (Matrix calculus and an Exponential function)
2) XY=600
3) The invisible writing
4) The shape of the message (R)

Having searched around, I think we have to decrypt an RSA cipher, using the product of XY and the public key to bust the private key this is coded in.

http://www.disappearing-inc.com/R/rsa.html

My maths isn't strong enough, without extreme revision, so if any one else can have a go....

Bel

[BBuck]

Morning, all.

Long-time listener, first-time poster. Sorry to come in as a newbie with a really long post, but this puzzle's been driving me round the twist (and I don't even have the card) and I've a couple of theories that might help, some of which I think are new to this forum.

First off, I don't think this is the civil war code, as this is not a cipher. A book code/cipher is possible, but I think unlikely, given XY=600. RSA seems a bit modern to count under the title. I also don't like the "R" theory, as the symbols could be better spaced to represent the letter more clearly.

I think there are two parts to the puzzle: a) the spaces and b) the second cipher. This fits well with Von's clue "twice as hard".

The spaces between the numbers have been mentioned before. There's also different line spacings, which do not alternate neatly - lines one and two are both big spaces. No idea on this.

I started from thinking that the minimum amount of information is on the note to make it harder to decrypt. Lines 2 and 3 appear to be the only "complete" lines: line 1 falls short (why is 264 not at the end - there's room?), and line 4 finishes roughly in line with 2 and 3, though it carries a gap. If this is right, then when you draw rough columns onto the note, it looks like there are 15 in all.

If lines 1 and 4 are missing a number, then it looks like the message alternates five numbers, four numbers, five numbers (based on lines 2 and 3, the only obviously "complete" lines), in a 15x7 grid. So there are 9 numbers missing. This might be account for the clue of the invisible writing, suggesting that there is more to the card than at first sight.

If this idea is right, then we can work out likely lengths of numbers (eg line 4 must be missing a three-symbol number). I don't have the card, so haven't seen the equations, but could they also help in filling in the grid?

Returning to the second cipher, I had a possible Eureka moment in the bath last night (though ran down the stairs rather than the street). I think that the answer might lie in digraphs. Instead of one number = one letter, it could represent two. This would tie in with the XY=600.

I can think of two ways to solve this. There is a famous French cipher called the Great Cipher, designed by the Rossignol family for Louis XIV (see The Code Book or Wiki). This used numbers up to 587 to represent syllables. I can't find a copy of the original list, though, so it's tricky to check.

A second approach, that doesn't require having access to outside texts, is to draw a 26x26 grid, marking the columns and rows a to z. Put 600 in the box at row x, column y, and count back. This makes ax=1, ay=2, etc.

Putting the numbers in to this gives the following ciphertext (- are where I think we might be missing numbers):

IWOKBE--
MPLATVPQNA
FPISSWCUIT
GJVJ--UW
JJ----BB--
UT--SU--
MW----TP--

or IWOKBE--MPLATVPQNAFPISSWCUITGJVJ--UWJJ----BB--UT--SU--MW----TP--

This might be encrypted with Vignère (probably one of the most famous ciphers of history). It's not long enough to look for repetitions to get the key length, but there is another way (pace The Code Book). Guess at some likely plaintext, and try it out in different positions. Reversing the process, then we can work out what key is needed. If some sensible English comes up, then the plaintext is probably correct and in the right place.

I've tried "the" in all possible positions, and there are some possiblities that make sense, but none definite. But there are longer possibilities: "Hales", "meet", "after", "class", "love", "professor" that might yield quicker routes to the solution. I'll try these soon, but might not get the chance until the weekend. Anyone know of a program out there that would speed things up?

Sorry again for such a long post, but hope there's something above that helps us nearer to a solution.

[doublecross]

Some nice ideas there, thanks.

I liked the 'digraph' idea, but (a) you don't know which way round your letters are and (b) I don't understand your numbering. The simplest way of arriving at XY=600 is by multiplying together their positions in the alphabet, X being 24th and Y 25th. That would give AX=24 and AY=25.

It would also mean that 208 is 16x13 or 8x26, giving PM, MP, HZ or ZH
352 is PV or VP
8 is AH, HA, BD or DB
305 is impossible as it is 5x61, the latter being a prime number.

[BBuck]

Ta. Apologies for not being clearer on the numbering.

The grid I had in mind would run similar to the one below, where you start at AA=1, fill out the row, and then continue from BA, etc:

a b c d ... z
a 1 2 3 4 ... 26
b 27 28 29 30 ... 52
c 53 54...
.
.
.
z ... 676

However, this would give XY=623, so 23 should be deducted from all numbers.

As all numbers up to 643 are thus included in the grid, there's no problems with the primes. Each number has a unique pair of coordinates where order is important: AX=1, but XA=576.

However, I take your point that I've made an assumption that the co-ordinates are read row, column, not column, row. But it might still be worth looking at on that basis, as it's a reasonable guess.

My biggest worry is that I've not been able to find a historical cipher that used this approach - still trying to find out more about the Rossignol's Great Cipher.

[ramsfan]

I've been trying out the various factors along doublecross's methods, both using the straightforward code, and putting it through atbash. That was because as was pointed out in one of the first posts, xy = 600 seems too big a coincidence to ignore. Whichever way you do it you come across primes. You can of course throw in any number of a's in the solution if the number isn't a prime. I'll try the idea of columns on the card and see if that leads to anything, ie not combining numbers. However that will obviously lead to only a restricted choice of numbers. There's never an israeli crypto math genius along the lines of avi in cryptonomicon when you need one.

[Juxta]

Finally got to looking over this one - interesting theories abound, but the first thing that crossed my mind when I saw Von's clue about "doubling" - has anyone attempted to mirror the image?

J, running tests in the lab, and lacking a mirror (but does have three episodes of Family Guy to sustain him!)

[GinGenie]

This might be worth looking into.

There is another Hebrew substitution cipher recorded which is based on Hebrew numbers called 'atbah'. The first nine numbers are substituted so they add up to 10, so alef (1) becomes tet (9), bet (2) becomes het (8) and so on. The next nine are substituted so they add up to 100, so yod (10) becomes tzadi (90) etc.

David Kahn (in The Codebreakers) says its unclear what happens with 19 onwards, but we do have XY=600. The Hebrew letters on the card only represent numbers up to 500 (final kaf), so maybe the x100 value letters should be substituted to add up to 600.

If the message is doubly encoded, this could be the first step, and then use the numbers in a nomenclator code. I tried the Tallmadge and Culper ones but came up with gibberish. Rossignols Great Ciper with 587 numbers used fits nicely, but I can't find it either!

[Maxamus]

can anyone confirm an awnser yet

[Maxamus]

can anyone confirm an awnser yet

[Maxamus]

sorry bout posting twice i pressed the right button but thought it was the wrong button so i pressed it again

[Belogroak]

More info on the card.

In invisible print you have the number 466 in Hebrew as shown earlier, you also have the following:

a line (vav?) after where 466 comes in the message, and at the curl of the R you have an R upside down.

regards

Bel

[Maxamus]

oh im having a brainwave
maybe their message is in the invisible ink and the visible writing is a decoy to make the teacher unable to read the correct message
i just bought a uv light so i will let you guys know my progress