# Thread: Great site!...playfair cipher calculator

1. ## Great site!...playfair cipher calculator

Here is a great place to test the playfair cipher:

http://www.simonsingh.net/The_Black_...faircipher.htm

Here's what I think:

I believe that we are looking to apply a keyword to a playfair cipher. I believe that this keyword will be a number. Not a digit per se but a spelled-out nunmber like "tweleve".

I think that we should be reading an excert of text and applying some sort of even code to that text that would resolve to a series of letters that make no sense (a playfair code). As an example if we took an even number like "2" and applied it to a string of text like "Dreamer One on Ending" and we wrote down every 2nd letter you would end up with a code that would read something like this:

RAEOENN

This serires of letters can then be used in the playfair ciper calculator using the proper keyword like "Tweleve" and it will rersolve into a message.

Cheers!

Cisco_Kid

2. Very nice. I like the thought that this would be a definite use of the text along with some ciphering that doesn't require a master's degree! This gives me something to do with all those strings of letters I keep coming up with.

3. Needs to say Hello!
Join Date
Jan 2005
Posts
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## Re: Great site!...playfair cipher calculator

Originally Posted by Cisco_Kid
This serires of letters can then be used in the playfair ciper calculator using the proper keyword like "Tweleve" and it will rersolve into a message.
While I do think the odd spelling of TWELEVE could lead to its use as a key, keep in mind that the Playfair Cipher (as well as many others) omit duplicate letters. So that for the purposes of the traditional Playfair Cipher "TWELVE" and "TWELEVE" would both be "TWELV".

4. Dylan,

Good point! I didn't even think of that! I'm pretty new to all this all this cipher stuff. This whole thing is making me feel pretty stupid. At this point I don't care who finds the treasure(s). I just want to know how to solve them. This book is killing me!!!

honeybee,
I keep coming up with strings of letters as well. I wonder if a masters degree would help?!?!?!? This can get pretty complicated! Let me know if you figure any of this out. I'm still working on it and will share any info I come up with.

Cheers!

Cisco_Kid

5. Be aware that the website given above has a programming error. It does not always form the digraphs correctly.

6. Originally Posted by rdshackleford
Be aware that the website given above has a programming error. It does not always form the digraphs correctly.
No kidding? I haven't noticed any of that. hmmm...puzzling.

7. For example, use "MANCHESTER" as the keyword, and "THIS SECRET" as the plaintext. It produces the following digraphs:

TH IS XS EC RE TX

The first X is not necessary and throws off the encryption.

I use a modified version of this website, with the software problem corrected.

8. Aren't the X's inserted whenever there is a double letter in the plaintext, or am I thinking of something else?

9. No, x's are only inserted when double letters occur within a pair (digraph). The reason is that a pair of letters must describe a rectangle in the grid. The plaintext letters are the remaining two corners of the rectangle. If you allowed double letters within a pair, you would not have a rectangle to describe ciphertext. Having repeated letters between two pairs is fine.

10. this is me chuckling at your siggy Dylan