Talk:Playfair cipher

Inadequate spec

How should one encode a sentence containing "xxx"? Or should the implementation crash for that case? --Rdm (talk) 05:04, 28 May 2014 (UTC)

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The REXX program handles these two examples (below) without problems.

Note the   (   [left parenthesis] is used to parse the plaintext from any specified options.

output when using the input of:   ( I like XXX better than XX beer.

old cipher key:  Playfair example.    ◄───using the default.
new cipher key:  PLAYFIREXM
     omit char:  J
   double char:  X
 original text:  I like XXX better then XX beer.

 cleansed text:  IL IK EX XX BE TT ER TH EN XX BE ER
                 ILIKEXXXBETTERTHENXXBEER

encrypted text:  RP BT XM MM MM DI WI VI IU DM QR MM DI MX EM
                 RPBTXMMMMMDIWIVIIUDMQRMMDIMXEM

    plain text:  IL IK EX XX XX BE TX TE RT HE NX XX BE XE RX
                 ILIKEXXXXXBETXTERTHENXXXBEXERX

 possible text:  IL IK EX XX BE TT ER TH EN XX BE ER
                 ILIKEXXXBETTERTHENXXBEER
 original text:  ILIKEXXXBETTERTHENXXBEER

════════════════Playfair encryption──► decryption──► encryption worked.

output when the input is:   (triple xxx is like, thirty, dude. No XXXX though. Bummer.

old cipher key:  Playfair example.    ◄───using the default.
new cipher key:  PLAYFIREXM
     omit char:  J
   double char:  X
 original text:  triple xxx is like, thirty, dude. No XXXX though. Bummer.

 cleansed text:  TR IP LE XX XI SL IK ET HI RT YD UD EN OX XX XT HO UG HB UM ME R
                 TRIPLEXXXISLIKETHIRTYDUDENOXXXXTHOUGHBUMMER

encrypted text:  UI BI AR MM MM MR NF BT IV BM IU AG VC RO QE MM MM MM ZB NV HB CT IM IX EM
                 UIBIARMMMMMRNFBTIVBMIUAGVCROQEMMMMMMZBNVHBCTIMIXEM

    plain text:  TR IP LE XX XX XI SL IK ET HI RT YD UD EN OX XX XX XX TH OU GH BU MX ME RX
                 TRIPLEXXXXXISLIKETHIRTYDUDENOXXXXXXXTHOUGHBUMXMERX

 possible text:  TR IP LE XX XI SL IK ET HI RT YD UD EN OX XX XT HO UG HB UM ME R
                 TRIPLEXXXISLIKETHIRTYDUDENOXXXXTHOUGHBUMMER
 original text:  TRIPLEXXXISLIKETHIRTYDUDENOXXXXTHOUGHBUMMER

════════════════Playfair encryption──► decryption──► encryption worked.