restart;
with(Maplets[Elements]):
rrep := proc(key)   
   local i, nkey, skey;
   nkey := "";
   skey := convert(convert(key,list), set);
   for i from 1 to length(key) do
      if member(key[i],skey) then
         nkey := cat(nkey, key[i]):
         skey := skey minus {key[i]};
      fi:
   od:
   nkey := StringTools[Select](StringTools[IsUpper], StringTools[UpperCase](nkey));
end:
playmat := proc(key)
   local rkey, abet, cabet, nr, nc, S, i, k, j;
   abet := "ABCDEFGHIKLMNOPQRSTUVWXYZ";
   rkey := rrep(key);
   cabet := cat(rkey, (StringTools[Remove](rcurry( member, {op(convert(rkey, list))} ),  
                       StringTools[UpperCase](convert(abet, string)))));
   S := Matrix(5,5); 
   ArrayTools[Fill]("", S); 
   k := 0;
   for i from 1 to 5 do
       for j from 1 to 5 do
           k := k + 1:           
           S[i,j] := substring(cabet, k);
       od:
   od: 
   S;
end:
sblock2 := proc(s)
    local i, pt, b;
    i := 1;
    pt := [];
    while i <= length(s) do
       b := substring(s, i..i+1);
       if length(b) = 1 then
          pt := [op(pt), cat(b[1], "X")];
          i := i + 1;
       else
          if b[1] <> b[2] then
             pt := [op(pt), cat(b[1], b[2])];
             i := i + 2;
          else
             pt := [op(pt), cat(b[1], "X")];
             i := i + 1;
          fi:
       fi:
    od:
    pt;
end:

fmatrc := proc(let, pmat)
    local i, j, res;
    for i from 1 to 5 do
        for j from 1 to 5 do
            if pmat[i, j] = let then
               res := [i, j];
               break:
            fi:
        od:
    od:
    res;
end:

gnewc := proc(oldc)
   local ctires;
   if oldc[2] < 5 then
      ctires := [oldc[1], oldc[2] + 1]
   else
      ctires := [oldc[1], (oldc[2] + 1) mod 5]
   fi:
   ctires;
end:

gnewr := proc(oldr)
   local ctires;
   if oldr[1] < 5 then
      ctires := [oldr[1] + 1, oldr[2]];
   else
      ctires := [(oldr[1] + 1) mod 5, oldr[2]];
   fi:
   ctires;
end:

fcti := proc(f, g)
   local i, ct1, ct2;
   if f[1] = g[1] then
      ct1 := gnewc(f);
      ct2 := gnewc(g);
   elif f[2] = g[2] then
      ct1 := gnewr(f);
      ct2 := gnewr(g);
   else
      ct1 := [ f[1], g[2] ];
      ct2 := [ g[1], f[2] ];
   fi:
   [ct1, ct2];
end:

gnewcd := proc(oldc)
   local ptires;
   if oldc[2] > 1 then
      ptires := [oldc[1], oldc[2] - 1]
   else
      ptires := [oldc[1], 5]
   fi:
   ptires;
end:

gnewrd := proc(oldr)
   local ptires;
   if oldr[1] > 1 then
      ptires := [oldr[1] - 1, oldr[2]];
   else
      ptires := [5, oldr[2]];
   fi:
   ptires;
end:
fpti := proc(f, g)
   local i, pt1, pt2;
   if f[1] = g[1] then
      pt1 := gnewcd(f);
      pt2 := gnewcd(g);
   elif f[2] = g[2] then
      pt1 := gnewrd(f);
      pt2 := gnewrd(g);
   else
      pt1 := [ f[1], g[2] ];
      pt2 := [ g[1], f[2] ];
   fi:
   [pt1, pt2];
end:
playfair := proc(text, keyw, type)
   local rrkeyw, pmat, textb2, i, let1, let2, p, q, s, tb, t;
   rrkeyw := rrep(StringTools:-SubstituteAll(keyw, "&rsquo;", "'"));
   pmat := playmat(rrkeyw); 
   textb2:= StringTools:-SubstituteAll(StringTools[Select](StringTools[IsUpper],  
            StringTools[UpperCase](StringTools:-SubstituteAll(text, "&rsquo;", "'"))), "J", "I");
   textb2 := sblock2(textb2);
   t := [];
   for i from 1 to nops(textb2) do
       let1 := textb2[i][1];
       let2 := textb2[i][2];
       p := fmatrc(let1, pmat);
       q := fmatrc(let2, pmat);
       if type = "encipher" then
          s := fcti(p, q);
       else
          s := fpti(p, q);
       fi:
       tb := cat( pmat[ op(s[1]) ], pmat[ op(s[2]) ] );
       t := [ op(t), tb];
   od: 
   convert(cat(op(t)), symbol);
end:
wsetup := proc(type)
    if type = "encipher" then
       Maplets:-Tools:-Set('TB1'('editable') = 'true', 'TB1'('foreground') = 'blue', 
                            'TF1'('editable') = 'true', 
                            'TB2'('foreground') = 'red', 'B1'('visible') = 'true', 
                            'B1'('enabled') = 'true', 'B1'('caption') = "Encipher Message");
    elif type = "decipher" then
       Maplets:-Tools:-Set('TB1'('editable') = 'true', 'TB1'('foreground') = 'red', 
                            'TF1'('editable') = 'true', 
                            'TB2'('foreground') = 'blue','B1'('visible') = 'true', 
                            'B1'('enabled') = 'true', 'B1'('caption') = "Decipher Message");
    fi:
end:
playfairmaplet := Maplet( Window( 'title'="Playfair Cipher", BoxColumn('background' = 'navy', BoxRow('background' = 'navy', BoxColumn('halign' = 'none', 'background' = 'navy', BoxRow('halign' = 'none', Label("Encipher or Decipher a message?",'font' = Font("arial", 17)), DropDownBox['DDB1']( 'value' = "?", ["?", "encipher", "decipher"], 'font' = Font("times", 15), 'width' = 80, onchange = Action(Evaluate('function' = "wsetup", Argument('DDB1', 'quotedtext' = 'true'))) ), seq(HorizontalGlue(), i = 1..30)),
    BoxRow('halign' = 'none', Label("Input Message:",  'font' = Font("arial", 17)), TextBox['TB1']('editable' = 'false', 'font' = Font("arial", bold, 16), 7..50), HorizontalGlue()),
    BoxRow('halign' = 'none', Label("Keyword: ", 'font' = Font("arial", 17)), TextBox['TF1']('editable' = 'false', 'background' = 'white', 1..20, 'font' = Font("arial", bold, 16)),  seq(HorizontalGlue(), i = 1..30)), BoxRow('halign' = 'none', Button['B1']('caption' = "         ", 'font' = Font("arial", bold, 15), 'enabled' = 'false', Evaluate('TB2' = "playfair", Argument('TB1', 'quotedtext' = 'true'), Argument('TF1', 'quotedtext' = 'true'), Argument('DDB1', 'quotedtext' = 'true') ) ), TextBox['TB2']( 'editable' = 'false', 'font' = Font("arial", bold, 16), 7..47 ),  HorizontalGlue())
    
 ), BoxColumn( seq(VerticalGlue(), i = 1..7), Label(Image("Playfair.jpg")), Label("Baron Lyon Playfair",'font' = Font("arial", 17)),  seq(VerticalGlue(), i = 1..10)), BoxColumn('background' = 'navy')), BoxRow('halign' = 'center', 'background' = 'navy', Button( "Clear All", 'font' = Font("arial", bold, 15), Action(SetOption('TB1' = "" ), SetOption('TB1'('editable') = 'false'), SetOption('TF1' = "" ), SetOption('TF1'('editable') = 'false'),   SetOption('TB2' = "" ), SetOption('B1'('caption') = "         "), SetOption('DDB1'('value') = "?"))  ), "    ",
     Button( "Quit", 'font' = Font("arial", bold, 15), Shutdown() ), "              "))) ):
Maplets[Display]( playfairmaplet ):
 
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