mdek.pas
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{$A+,B+,D-,E+,F+,I+,L+,N-,O+,R-,S+,V-}
unit mdek;
interface
{rcg11172000 no overlay under Linux.}
{uses overlay;}
function encrypt(os:string; c1,c2,c3,c4,c5,c6:byte):string;
function decrypt(os:string; c1,c2,c3,c4,c5,c6:byte):string;
implementation
function encrypt(os:string; c1,c2,c3,c4,c5,c6:byte):string;
var ns:string;
codes:array[1..6] of byte;
c,d,i,j,k,l:integer;
begin
for i:=1 to 6 do
case i of 1:codes[i]:=c1; 2:codes[i]:=c2; 3:codes[i]:=c3;
4:codes[i]:=c4; 5:codes[i]:=c5; 6:codes[i]:=c6; end;
j:=0; k:=1; l:=1;
for i:=1 to length(os) do begin
inc(j);
if (j>6) then begin
dec(k); j:=1;
if (k<1) then begin
dec(l); k:=6;
if (l<1) then begin
j:=1; k:=6; l:=6;
end;
end;
end;
d:=codes[j]+codes[k]+codes[l];
os[i]:=chr((ord(os[i])+d) mod 256);
end;
encrypt:=os;
end;
function decrypt(os:string; c1,c2,c3,c4,c5,c6:byte):string;
var ns:string;
codes:array[1..6] of byte;
c,d,i,j,k,l:integer;
begin
for i:=1 to 6 do
case i of 1:codes[i]:=c1; 2:codes[i]:=c2; 3:codes[i]:=c3;
4:codes[i]:=c4; 5:codes[i]:=c5; 6:codes[i]:=c6; end;
j:=0; k:=1; l:=1;
for i:=1 to length(os) do begin
inc(j);
if (j>6) then begin
dec(k); j:=1;
if (k<1) then begin
dec(l); k:=6;
if (l<1) then begin
j:=1; k:=6; l:=6;
end;
end;
end;
d:=codes[j]+codes[k]+codes[l];
os[i]:=chr((1024+(ord(os[i])-d)) mod 256);
end;
decrypt:=os;
end;
end.