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Challenge "Playfair Encryption"

Challenge "Playfair Encryption"  

  By: admin on Dec. 22, 2010, 7:48 a.m.

In this challenge you shall break the Playfair encryption which was used by the British forces in the Crimean War and in World War I, among others.
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 Last edited by: admin on Oct. 31, 2021, 2:54 a.m., edited 1 time in total.

Re: Challenge "The Playfair Encryption"  

  By: shtywi on Jan. 8, 2011, 11:21 a.m.

SORRY BUT GIVE ME MORE HINTS.

Re: Challenge "The Playfair Encryption"  

  By: michaelm on Jan. 9, 2011, 10:35 a.m.

SORRY BUT GIVE ME MORE HINTS.

Ich könnte auch etwas Hilfe brauchen.

Haben Text1 und Text2 das gleiche Schlüsselwort?

Und wie kurz ist ein relativ kurzer Schlüssel? Bei bis zu 5-stelligen englischen Wörtern habe ich noch keine Lösung gefunden

Re: Challenge "The Playfair Encryption"  

  By: Schoetti on Jan. 10, 2011, 11:55 a.m.

Hi there,

yes, both texts do have the same key and short key means less than 10 characters… And if you read a little about the Playfair encryption you'll see that if you know that a short key is used, there are, with a high probability, more information included…

Hope this information helps you…

Regards

Pascal

Re: Challenge "The Playfair Encryption"  

  By: inventormoreno on Feb. 3, 2011, 12:50 a.m.

In this challenge you shall break the Playfair encryption which was used by the British forces in the Crimean War and in World War.

Read more...
The only thing I need to break the CODE is a KEYWORD. Is there any keyword you can provide? If not, let me know so I can redrawing my matrix. Thanks!

Re: Challenge "The Playfair Encryption"  

  By: Schoetti on Feb. 3, 2011, 11:26 a.m.

Hi,

you are right, if you know the keyword(s) (it doesn't necessarily have to be one word) you´ll break the cipher. So, what would be the point to provide the keyword(s)? For that is what you should find out…

If you face more problems you are invited to write me a personal message here!

Cheers,

Pascal

Re: Challenge  

  By: silva on June 23, 2017, 10:25 p.m.

Hi
Where can I find more information how to solve this playfair encryption?
I did a bigram frequency analysis and found several frequently used bigrams. But even with a short keyword, like for example codewordis almost everything possible. I don`t know how to continue after de bigram frequencies. I found nothing with Google on playfair decryption with short keywords.
I assume it is possible to solve this challenge without just guessing some fictitious author.
Please some information.

Thanx Silva

Re: Challenge  

  By: argh on July 11, 2017, 2:48 p.m.

Hi Silva,

I don`t know how to continue after de bigram frequencies.

Surely you don't mean german (de) bigram frequencies? The plaintext is in english.

If all other methods fail, you could always try a hillclimbing approach to find the solution (log-trigram cost function should do the trick).

Armin

Re: Challenge  

  By: glasshopper on Oct. 6, 2020, 1:14 a.m.

With 25! (15,511,210,043,330,985,984,000,000) possible KeySquares and
only bigram and quadragram frequencies to start from,
I can't believe this is only Level I… [HTML_REMOVED]


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