gint.pas

rsa加密算法实例

                  If x[6] = '0' Then g := 31 Else g := 32;
               End
            End
         End
      End
   End
   Else
   Begin
      If x[2] = '0' Then
      Begin
         If x[3] = '0' Then
         Begin
            If x[4] = '0' Then
            Begin
               If x[5] = '0' Then
               Begin
                  If x[6] = '0' Then g := 33 Else g := 34;
               End
               Else
               Begin
                  If x[6] = '0' Then g := 35 Else g := 36;
               End
            End
            Else
            Begin
               If x[5] = '0' Then
               Begin
                  If x[6] = '0' Then g := 37 Else g := 38;
               End
               Else
               Begin
                  If x[6] = '0' Then g := 39 Else g := 40;
               End
            End
         End
         Else
         Begin
            If x[4] = '0' Then
            Begin
               If x[5] = '0' Then
               Begin
                  If x[6] = '0' Then g := 41 Else g := 42;
               End
               Else
               Begin
                  If x[6] = '0' Then g := 43 Else g := 44;
               End
            End
            Else
            Begin
               If x[5] = '0' Then
               Begin
                  If x[6] = '0' Then g := 45 Else g := 46;
               End
               Else
               Begin
                  If x[6] = '0' Then g := 47 Else g := 48;
               End
            End
         End
      End
      Else
      Begin
         If x[3] = '0' Then
         Begin
            If x[4] = '0' Then
            Begin
               If x[5] = '0' Then
               Begin
                  If x[6] = '0' Then g := 49 Else g := 50;
               End
               Else
               Begin
                  If x[6] = '0' Then g := 51 Else g := 52;
               End
            End
            Else
            Begin
               If x[5] = '0' Then
               Begin
                  If x[6] = '0' Then g := 53 Else g := 54;
               End
               Else
               Begin
                  If x[6] = '0' Then g := 55 Else g := 56;
               End
            End
         End
         Else
         Begin
            If x[4] = '0' Then
            Begin
               If x[5] = '0' Then
               Begin
                  If x[6] = '0' Then g := 57 Else g := 58;
               End
               Else
               Begin
                  If x[6] = '0' Then g := 59 Else g := 60;
               End
            End
            Else
            Begin
               If x[5] = '0' Then
               Begin
                  If x[6] = '0' Then g := 61 Else g := 62;
               End
               Else
               Begin
                  If x[6] = '0' Then g := 63 Else g := 64;
               End
            End
         End
      End
   End
End;



Procedure initialize8(Var trans : Array Of String);
Var
   c1, c2, c3, c4, c5, c6, c7, c8 : integer;
   x : String;
   g : char;
Begin
   For c1 := 0 To 1 Do
      For c2 := 0 To 1 Do
         For c3 := 0 To 1 Do
            For c4 := 0 To 1 Do
               For c5 := 0 To 1 Do
                  For c6 := 0 To 1 Do
                     For c7 := 0 To 1 Do
                        For c8 := 0 To 1 Do
                        Begin
                           x := '';
                           x := inttostr(c1) + inttostr(c2) + inttostr(c3) + inttostr(c4) + inttostr(c5) + inttostr(c6) + inttostr(c7) + inttostr(c8);
                           zeronetochar8(g, x);
                           trans[ord(g)] := x;
                        End;
End;



Procedure initialize6(Var trans : Array Of String);
Var
   c1, c2, c3, c4, c5, c6 : integer;
   x : String;
   g : integer;
Begin
   For c1 := 0 To 1 Do
      For c2 := 0 To 1 Do
         For c3 := 0 To 1 Do
            For c4 := 0 To 1 Do
               For c5 := 0 To 1 Do
                  For c6 := 0 To 1 Do
                  Begin
                     x := '';
                     x := inttostr(c1) + inttostr(c2) + inttostr(c3) + inttostr(c4) + inttostr(c5) + inttostr(c6);
                     zeronetochar6(g, x);
                     trans[ord(chr64[g])] := x;
                  End;
End;


// Convert 8 bit strings to 6 bit strings and visa versa

Procedure Convert8to6bit(str8 : String; Var str6 : String);
Var
   temp : String;
   trans : Array[0..255] Of String;
   i, len6 : longint;
   g : integer;
Begin
   initialize8(trans);
   temp := '';
   For i := 1 To length(str8) Do temp := temp + trans[ord(str8[i])];
   While (length(temp) Mod 6) <> 0 Do temp := temp + '0';
   len6 := length(temp) Div 6;
   str6 := '';
   For i := 1 To len6 Do
   Begin
      zeronetochar6(g, copy(temp, 1, 6));
      str6 := str6 + chr64[g];
      delete(temp, 1, 6);
   End;
End;


Procedure Convert6to8bit(str6 : String; Var str8 : String);
Var
   temp : String;
   trans : Array[0..255] Of String;
   i, len8 : longint;
   g : char;
Begin
   initialize6(trans);
   temp := '';
   For i := 1 To length(str6) Do temp := temp + trans[ord(str6[i])];
   str8 := '';
   len8 := length(temp) Div 8;
   For i := 1 To len8 Do
   Begin
      zeronetochar8(g, copy(temp, 1, 8));
      str8 := str8 + g;
      delete(temp, 1, 8);
   End;
End;


// Convert 8 & 6 bit strings to 1 bit strings and visa versa

Procedure Convert8to1bit(str8 : String; Var str1 : String);
Var
   trans : Array[0..255] Of String;
   i : longint;
Begin
   str1 := '';
   initialize8(trans);
   For i := 1 To length(str8) Do str1 := str1 + trans[ord(str8[i])];
End;


Procedure Convert6to1bit(str6 : String; Var str1 : String);
Var
   trans : Array[0..255] Of String;
   i : longint;
Begin
   str1 := '';
   initialize6(trans);
   For i := 1 To length(str6) Do str1 := str1 + trans[ord(str6[i])];
End;


Procedure Convert1to8bit(str1 : String; Var str8 : String);
Var
   i, len8 : longint;
   g : char;
Begin
   str8 := '';
   While (length(str1) Mod 8) <> 0 Do str1 := '0' + str1;
   len8 := length(str1) Div 8;
   For i := 1 To len8 Do
   Begin
      zeronetochar8(g, copy(str1, 1, 8));
      str8 := str8 + g;
      delete(str1, 1, 8);
   End;
End;


Procedure Convert1to6bit(str1 : String; Var str6 : String);
Var
   i, len6 : longint;
   g : integer;
Begin
   str6 := '';
   While (length(str1) Mod 6) <> 0 Do str1 := '0' + str1;
   len6 := length(str1) Div 6;
   For i := 1 To len6 Do
   Begin
      zeronetochar6(g, copy(str1, 1, 6));
      str6 := str6 + chr64[g];
      delete(str1, 1, 6);
   End;
End;


// convert a base 10 string to a GInt and visa versa

Procedure DecStrToGInt(GIntstr : String; Var GInt : TGInt);
Var
   temp1, temp2 : TGInt;
   p : Tsign;
Begin

   While Not (GIntstr[1] In ['-', '0'..'9']) Do delete(GIntstr, 1, 1);

   If GIntstr[1] = '-' Then
   Begin
      delete(GIntstr, 1, 1);
      p := negative;
   End
   Else p := positive;

   While (GIntstr[1] = '0') And (length(GIntstr) > 1) Do delete(GIntstr, 1, 1);

   new(temp2);
   temp2^.next := Nil;
   If (length(GIntstr) Mod 4) = 0 Then
   Begin
      temp2^.value := strtoint(copy(GIntstr, 1, 4));
      delete(GIntstr, 1, 4);
   End
   Else
   Begin
      temp2^.value := strtoint(copy(GIntstr, 1, (length(GIntstr) Mod 4)));
      delete(GIntstr, 1, (length(GIntstr) Mod 4));
   End;

   While length(GIntstr) > 0 Do
   Begin
      new(temp1);
      temp1^.next := temp2;
      temp2^.prev := temp1;
      temp1^.value := strtoint(copy(GIntstr, 1, 4));
      delete(GIntstr, 1, 4);
      temp2 := temp1;
   End;

   temp2^.prev := Nil;
   temp2^.sign := p;
   GInt := temp2;

End;


Procedure GIntToDecStr(Var GIntstr : String; GInt : TGInt);
Var
   s : String;
   p : TSign;
Begin
   GIntstr := '';
   p := GInt^.sign;

   s := inttostr(GInt^.value);
   While length(s) < 4 Do s := '0' + s;
   GIntstr := s + GIntstr;
   While GInt^.next <> Nil Do
   Begin
      GInt := GInt^.next;
      s := inttostr(abs(GInt^.value));
      While length(s) < 4 Do s := '0' + s;
      GIntstr := s + GIntstr;
   End;

   While (GIntstr[1] = '0') And (length(GIntstr) > 1) Do delete(GIntstr, 1, 1);

   If p = negative Then GIntstr := '-' + GIntstr;

End;


// Convert an integer to a GInt

Procedure IntToGInt(Int : integer; Var GInt : TGInt);
Begin
   DecstrtoGInt(inttostr(Int), GInt);
End;


// Destroy a GInt, in order to free memory

Procedure GIntDestroy(Var GInt : TGInt);
Begin

   While GInt^.next <> Nil Do GInt := GInt^.next;

   While GInt^.prev <> Nil Do
   Begin
      GInt := GInt^.prev;
      dispose(GInt^.next);
   End;
   dispose(GInt);
End;


// Make a copy of a GInt

Procedure GIntCopy(GInt1 : TGInt; Var GInt2 : TGInt);
Var
   temp1, temp2 : TGInt;
Begin
   new(GInt2);
   GInt2^.sign := GInt1^.sign;
   GInt2^.prev := Nil;
   GInt2^.value := GInt1^.value;
   temp1 := GInt2;
   While GInt1^.next <> Nil Do
   Begin
      GInt1 := GInt1^.next;
      new(temp2);
      temp2^.value := GInt1^.value;
      temp2^.prev := temp1;
      temp1^.next := temp2;
      temp1 := temp2;
   End;
   temp1^.next := Nil;
End;


// Divide a GInt by an integer, GInt = res * by + m