A New/Old code Just For Fun
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From: Paulo Marques on 21 Jul 2010 07:55 Fiziwig wrote: > On Jul 20, 10:47 am, Paulo Marques <pmarq...(a)grupopie.com> wrote: >> Hi, >>[...] > I wanted to keep it as simple as possible for a human being using a > hard copy code book and pencil and paper. More optimal encodings, > while more efficient, would necessarily be more complex for use by > mere humans. I don't see a reason for that. If you calculate the optimal encoding using huffman and then write the "codebook" in alphabetical sorting order, there is no reason for it to be more difficult to use. > And don't forget, if the empire falls and civilization > crumbles, future feudal lords and kings will once again have to rely > on paper and pencil cryptography. ;-) Even on such a scenario, the huffman algorithm is easy enough to be executed by hand... >[...] >> This group takes cryptography seriously and your description just sounds >> like an extremely "weak" cypher... > > Yes, very weak indeed. But I'm enjoying the project all the same. And > besides, Byrne's "weak" cipher resisted cracking for many decades. > (See my functional equivalent of the Choacipher machine at > http://fiziwig.com/crypto/tile1.html ) Yes, because it didn't respect the Kerckhoffs' principle [1], so only cryptographers with nothing better to do would even consider looking at it. The moment the algorithm was made public, it was just a question of days (IIRC) before it fell apart... >> If you want a practical way to encrypt/decrypt emails to/from friends, >> just take a look at gpg. > > yes, there are better ways to encrypt email for security, but this is > a pencil and paper system, which appeals to my retro nature. There are other pencil and paper systems out there, that have at least not been completely broken yet and respect the Kerckhoffs' principle, like Solitaire [2]. -- Paulo Marques - www.grupopie.com "I used to be indecisive, but now I'm not so sure." [1] http://en.wikipedia.org/wiki/Kerckhoffs%27_principle [2] http://www.schneier.com/solitaire.html http://en.wikipedia.org/wiki/Solitaire_%28cipher%29
From: Fiziwig on 21 Jul 2010 15:12 On Jul 21, 4:55 am, Paulo Marques <pmarq...(a)grupopie.com> wrote: > Fiziwig wrote: > > On Jul 20, 10:47 am, Paulo Marques <pmarq...(a)grupopie.com> wrote: > >> Hi, > >>[...] > > I wanted to keep it as simple as possible for a human being using a > > hard copy code book and pencil and paper. More optimal encodings, > > while more efficient, would necessarily be more complex for use by > > mere humans. > > I don't see a reason for that. If you calculate the optimal encoding > using huffman and then write the "codebook" in alphabetical sorting > order, there is no reason for it to be more difficult to use. You right. I guess I was thinking in terms of splitting the ciphertext stream into words. The rule that if you have a two or three letter code group ending in {U,V,W,X,Y,Z} you need to take the next letter from the ciphertext stream and add it to the code group made the self- segregation _seem_ easier to perform. On the other hand, if the next two code letters were "MQ" and there was no "MQ" in the code dictionary, then you would have to include the next letter, say "R" and look up "MQR", and so on until you found the shortest code group in the ciphertext stream that had a dictionary equivalent. Yes, that would work. I stand corrected. I shall have to rebuild the dictionary using the Huffman algorithm and see what it looks like. > > > And don't forget, if the empire falls and civilization > > crumbles, future feudal lords and kings will once again have to rely > > on paper and pencil cryptography. ;-) > > Even on such a scenario, the huffman algorithm is easy enough to be > executed by hand... Yes, I suppose that's true. thank you for your constructive input. --gary
From: rossum on 21 Jul 2010 16:59 On Tue, 20 Jul 2010 13:52:30 -0700 (PDT), Fiziwig <fiziwig(a)gmail.com> wrote: >I wanted to keep it as simple as possible for a human being using a >hard copy code book and pencil and paper. Playfair. rossum
From: WTShaw on 21 Jul 2010 19:23 On Jul 20, 3:57 pm, Fiziwig <fizi...(a)gmail.com> wrote: > On Jul 20, 11:06 am, Mok-Kong Shen <mok-kong.s...(a)t-online.de> wrote: > > > Fiziwig wrote: > > > Encoded, the average is 2.35 Roman letters per English word, or about > > > half the size of the same message in English plaintext. [snip] > > > Question: Would the efficiency be better if a larger alphabet, e.g. > > both upper and lower case, be used? > > > (BTW, a different line of thought is in my post "A scheme of dictionary > > coding of English words" of 29.06.2010.) > > > M. K. Shen > > I'm sure the compression would be better using upper and lower case, > however, as a paper-and-pencil system there is too much room for > confusion over uppercase and lower case hand-printed letters. In > particular Cc, Kk, Ll, Oo, Pp, Ss, Uu, Vv, Xx, Yy, Zz. Since it is > meant to be a paper-and-pencil system, that would make it too error- > prone. > > I looked at your system. Very compact, but again, I prefer to stick to > all upper case Roman letters for hand-written clarity. > > --gary For had work, it is good that you see the error prone methods first hand. The same is with the addition of digits as only a few can be so added.
From: WTShaw on 21 Jul 2010 19:25
On Jul 21, 3:59 pm, rossum <rossu...(a)coldmail.com> wrote: > On Tue, 20 Jul 2010 13:52:30 -0700 (PDT), Fiziwig <fizi...(a)gmail.com> > wrote: > > >I wanted to keep it as simple as possible for a human being using a > >hard copy code book and pencil and paper. > > Playfair. > > rossum Playfair, not so great. Yes, hard by hand, but vulnerable by machine. |