Re: Double transposition cryptanalysis

From: Stewart Strait (sstrait1_at_san.rr.com)
Date: 11/27/05 

Date: Sun, 27 Nov 2005 10:17:10 GMT

Stefan Krah <sfk1@bigfoot.com> wrote:
> * Stewart Strait <sstrait1@san.rr.com> wrote:
> ...
> [ http://www.speakeasy.org/~straits/straits08.clb ]
>
> > I'll provide keys for other examples. The ones on the web are very
> > old and no one except possibly Jim Gillogly has ever claimed to
> > have solved one, although a number of people on sci.crypt almost
> > certainly could have solved them if they were interested.
>
> I came across this last weekend and indeed solving them went pretty smooth.
> Example number 006 from straits08.clb has the longest key (22) and begins
> with "ontheeasternshoreofourlake".
>
> Stefan Krah

Congratulations.

Two more examples follow. They are cleaner in the sense that they
have keys longer than the square root of the message length, so they
can't be solved as single incomplete columnars. The second example
has an original plaintext. It wasn't my intention that people deduce
the source of some of my non-original plaintext, but such deductions
are also part of cryptanalysis. (I'm assuming Stefan Krah's "pretty
smooth" solving meant that he solved everything as a double
transposition from the outset and didn't undertake the labor of
searching for the source of the plaintext.)

I don't have knowledge or experience to decide whether an entry
into the example solved by Stefan Krah with key length 22 could
really be obtained by treating it as a single transposition.
It would have 484=22*22 columns, 423 of length 2 and 61 of
length 1, and a ragged bottom edge of the grid.

straits30.073 DOUBLE INCOMPLETE COLUMNAR; 1 KEY OF LENGTH 26--35
KEESE USGVE ELESU WEALT EHIDM OELYE IWTTW ASEYE LRAOG NSENT UAETA NDLMO
TOTPE VHAHS HIOIB AEENE NDIRE SHWDF TATTE EETHH REDHV NDOEO ROEIS TDSCL
TEORT SADCL AOWHS EOFRS HHIHK ASSUO ESNTS NGAED GNHTR PISOS DLSUF USHMR
GUBAT ETSTE AORIA DEIZS ELNTE RSYZN OSONO DKAED LOFHQ TAUSR NNHSU TLERT
OETHO GRIAS ECARH NNATI AUNCN WEAEA HFSOE WCSHI DCSAA TUMSI HICIH DBROA
AILEH INEDA WHALH GFHRE DUSED TRNHF NIATA UEEOH TROSN AETOW RDETE NASFS
SICHN DAUPI OHHAN TTORE EANRE INDID NWMRE EEEGT KAEKG IEHNL NROAD TTSLL
LDTIA AEHIL HFRAT EHDEE EMRUC EYFEF TUTIT NASSL CNTII EHBMY BTNYI ESGAG
ARTIC THYTH MDLOL RANHN EGS

straits_05b26a.cm DOUBLE INCOMPLETE COLUMNAR; 1 KEY OF LENGTH 22--28
CAILA PSSRW IEEVF TNHIE DTDSA MOIPE MLHCT TSSDI LADNT WNOYF ERAHU WTTEE
EIISH NALCC MALOA EBRNL ERSNN RLMNS IMETO CFHTN SERAI OFMRF EDBAI EAUAE
CIDHT TEOAV SDTNR TNUER OTADB SVGIT TNOAX WLVAE YACWE NTEAG LWTRI RCISD
VQARH PRLRL OEBON RASSY PRMRO WRELA INACT EKDGE HAANP YEKOS CNPUY IRCAE
TBREI APDII ODFIO WYHET DHWAN IOEKE RETCE HUIOI OHHRE LIERE DTELL SERVE
EETAA OETIN SABAT LICCP CIEND STEIE TVTWY IAADH IENIT UUOLN NOOOS OILRP
ENSVI NMTPI TOFIM PMIAG LSGEI EPKHR IRTIE EIWNT NRSTD IRINT VRHEM MFOIL
RSEES MUNHA NEMOO TRAEM ARGOE EN

Stewart Strait

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