Взломать детский шифр

{PascalABC.NET}
library lib9;
interface
  function CryptographySC9(data, key, iv:array of byte; mode:boolean):array of byte;
implementation
function OpenText1to2(x:array of byte):array [,] of byte;
begin
  var a:integer := x.Length;
  var b:array [,] of byte := new byte [8, ((a div 8) + 1)];
  var c:integer := 0;
  try
    for var i:integer := 0 to (a div 8) do
      for var ci:integer := 0 to 7 do
      begin
        b[ci, i] := x[c];
        c := (c + 1);
      end;
  except on System.IndexOutOfRangeException do
    begin
    end;
  end;
  b[7, (a div 8)] := (8 - (a mod 8));
  Result := b;
end;
 
function OpenText2to1(x:array [,] of byte):array of byte;
begin
  var a:integer := x[7, (x.GetLength(1) - 1)];
  var b:array of byte := new byte [x.Length - a];
  a := 0;
  try
    for var i:integer := 0 to (x.GetLength(1) - 1) do
      for var ci:integer := 0 to 7 do
      begin
        b[a] := x[ci, i];
        a := (a + 1);
      end;
  except on System.IndexOutOfRangeException do
    begin
    end;
  end;
  Result := b;
end;
 
function Transform2to1(x:array [,] of byte):array of byte;
begin
  var a:array of byte := new byte [x.Length];
  var b:integer := 0;
  for var i:integer := 0 to (x.GetLength(1) - 1) do
    for var ci:integer := 0 to 7 do
    begin
      a[b] := x[ci, i];
      b := (b + 1);
    end;
  Result := a;
end;
 
function Transform1to2(x:array of byte):array [,] of byte;
begin
  var a:integer := (x.Length div 8);
  var b:array [,] of byte := new byte [8, a];
  var c:integer := 0;
  for var i:integer := 0 to (a - 1) do
    for var ci:integer := 0 to 7 do
    begin
      b[ci, i] := x[c];
      c := (c + 1);
    end;
  Result := b;
end;
 
procedure IVT(var x:array [,] of byte; iv:array of byte);
begin
  for var i:integer := 0 to 7 do x[i, 0] := (x[i, 0] xor iv[i]);
end;
 
function BigIntToByteArr(x:System.Numerics.BigInteger):array of byte;
begin
  var a:array of byte := x.ToByteArray();
  var b:array of byte := new byte [4];
  for var i:integer := 0 to 3 do b[i] := 0;
  try
    for var i:integer := 0 to 3 do b[i] := a[i];
  except on System.IndexOutOfRangeException do
    begin
    end;
  end;
  Result := b;
end;
 
function BigIntToUint32(x:System.Numerics.BigInteger):longword;
begin
  Result := System.BitConverter.ToUInt32(BigIntToByteArr(x), 0);
end;
 
function ToByteArr(x:longword):array of byte;
begin
  var a:System.Numerics.BigInteger := x;
  Result := BigIntToByteArr(a);
end;
 
function FFN1(x, y:longword):longword;
begin
  var a:System.Numerics.BigInteger := (x + 2 * y + 79813);
  Result := BigIntToUint32((a * a * a + a + 21379) mod 168248124743);
end;
 
function FFN2(x, y:longword):longword;
begin
  var a:System.Numerics.BigInteger := (x + 3 * y + 4159);
  Result := BigIntToUint32((a * a * a * a * a + a * a + 161233) mod 2939384514263);
end;
 
procedure FeistelNetwork(var x:array [,] of byte; RKey:array of longword; index:integer; first:boolean);
begin
  var a, b, g:longword;
  var s:array of byte := new byte [8];
  for var i:integer := 0 to 7 do s[i] := x[i, index];
  a := System.BitConverter.ToUInt32(s, 0);
  b := System.BitConverter.ToUInt32(s, 4);
  for var i:integer := 0 to 7 do
  begin
    if first then g := FFN1(a, RKey[i])
       else g := FFN2(a, RKey[i]);
    b := (g xor b);
    if (i <> 7) then Swap(a, b);
  end;
  var w:array of byte := ToByteArr(a);
  for var i:integer := 0 to 3 do x[i, index] := w[i];
  w := ToByteArr(b);
  for var i:integer := 4 to 7 do x[i, index] := w[i - 4];
end;
 
function FLW(x, y:longword):longword;
begin
  var a, b:System.Numerics.BigInteger;
  a := x;
  b := y;
  Result := BigIntToUint32(((a + 723319) * (b + 56311477) + 5119) mod 527845764689);
end;
 
function FLW2(x, y:longword):longword;
begin
  var a, b:System.Numerics.BigInteger;
  a := x;
  b := y;
  Result := BigIntToUint32(((a + 97522913) * (b + 26635429) + 426073) mod 3894575586631);
end;
 
function RoundKey(var key:array of byte; y:array of byte; usingReverse, first:boolean):array of longword;
begin
  var a:array of longword := new longword [2];
  for var i:integer := 0 to 7 do key[i] := (key[i] xor y[i]);
  a[0] := System.BitConverter.ToUInt32(key, 0);
  a[1] := System.BitConverter.ToUInt32(key, 4);
  var b:array of longword := new longword [8];
  for var i:integer := 0 to 3 do
    for var ci:integer := 0 to 1 do b[i * 2 + ci] := a[ci];
    
  for var i:integer := 0 to 7 do
    for var ci:integer := 0 to 7 do
      if first then b[ci] := FLW(b[ci], b[i])
          else b[ci] := FLW2(b[ci], b[i]);
  if usingReverse then System.Array.Reverse(b);
  Result := b;
end;
 
procedure BlockTransform(var x:array [,] of byte; var a, s:array of byte; mode1, mode2:boolean; i:integer);
begin
  var b:array of longword := RoundKey(a, s, (not mode1), mode2);
  for var ci:integer := 0 to 7 do s[ci] := x[ci, i];
  FeistelNetwork(x, b, i, mode2);
  for var ci:integer := 0 to 7 do s[ci] := (s[ci] xor x[ci, i]);
end;
 
procedure TransformCryptography(var x:array [,] of byte; Key:array of byte; mode, first:boolean);
begin
  var a, s:array of byte;
  a := new byte [8]; s := new byte [8];
  for var i:integer := 0 to 7 do
  begin
    a[i] := Key[i];
    s[i] := 0;
  end;
  if first then for var i:integer := 0 to (x.GetLength(1) - 1) do
      BlockTransform(x, a, s, mode, true, i)
    else for var i:integer := (x.GetLength(1) - 1) downto 0 do
      BlockTransform(x, a, s, mode, false, i);
end;
 
function CryptographySC9(data, key, iv:array of byte; mode:boolean):array of byte;
begin
  var b:array of byte;
  if mode then
   begin
     var a:array [,] of byte := OpenText1to2(data);
     IVT(a, iv);
     TransformCryptography(a, key, true, true);
     TransformCryptography(a, key, true, false);
     b := Transform2to1(a);
   end
  else
   begin
     var a:array [,] of byte := Transform1to2(data);
     TransformCryptography(a, key, false, false);
     TransformCryptography(a, key, false, true);
     IVT(a, iv);
     b := OpenText2to1(a);
   end;
   Result := b;
end;
 
end.

{$reference lib9.dll}
 
begin
  var a:string := '';
  Write('file > ');
  Readln(a);
  var b:array of byte := System.IO.File.ReadAllBytes(a);
  Writeln('iv:');
  var c:array of byte := new byte [8];
  for var i:integer := 0 to 7 do
  begin
    Write(i.ToString() + ' > ');
    c[i] := 0;
    Readln(c[i]);
  end;
  Writeln();
  var d:array of byte := new byte [8];
  Writeln('key:');
  for var i:integer := 0 to 7 do
  begin
    Write(i.ToString() + ' > ');
    d[i] := 0;
    Readln(d[i]);
  end;
  var g:boolean := false;
  Write('mode > ');
  Readln(g);
  a := '';
  Write('save result > ');
  Readln(a);
  System.IO.File.WriteAllBytes(a, lib9.lib9.CryptographySC9(b, d, c, g));
end.

function FFN1(x, y:longword):longword;
var a:longword;
begin
  Result := (x * 977  + y + 1411) mod 9973;
end;

  /// 1
  L1:=L;
  R1:=R xor FFN1(L1, 1461);

function FFN1(x, y:longword):longword;
begin
  var a, b, c, d:System.Numerics.BigInteger;
  a := (x + 79813);
  b := ((a * a * a + a + 21379) mod 168248124743);
  c := (y + 4159);
  d := ((c * c * c * c * c + c * c + 161233) mod 2939384514263);
  
  Result := (BigIntToUint32(b) xor BigIntToUint32(d));
end;

function BigIntToByteArr(x:System.Numerics.BigInteger):array of byte;
begin
  var a:array of byte := x.ToByteArray();
  var b:array of byte := new byte [4];
  for var i:integer := 0 to 3 do b[i] := 0;
  try
    for var i:integer := 0 to 3 do b[i] := a[i];
  except on System.IndexOutOfRangeException do
    begin
    end;
  end;
  Result := b;
end;
 
function BigIntToUint32(x:System.Numerics.BigInteger):longword;
begin
  Result := System.BitConverter.ToUInt32(BigIntToByteArr(x), 0);
end;
 
function FFN1(x, y:longword):longword;
begin
  var a, b, c, d:System.Numerics.BigInteger;
  a := (x + 79813);
  b := ((a * a * a + a + 21379) mod 168248124743);
  c := (y + 4159);
  d := ((c * c * c * c * c + c * c + 161233) mod 2939384514263);
  
  Result := (BigIntToUint32(b) xor BigIntToUint32(d));
end;
 
begin
  var a:array of longword := new longword [10000];
  for var i:integer := 0 to 99 do
    for var ci:integer := 0 to 99 do
    a[i * 100 + ci] := FFN1(i, ci);
   
   var b:integer := 0;
   for var i:integer := 0 to 9999 do
     for var ci:integer := 0 to 9999 do
     begin
       if (i = ci) then continue;
       if (a[i] = a[ci]) then b := (b + 1);
     end;
     Writeln('повторений: ', b);
     Readln();
end.

  
  a := (x * 977 + 1411) mod 9973;
  b := (y * 973 + 1811) mod 9943;
  Result:= a xor b;

a := (x * x * x * x * x * 631 + x * x * x * x * 313 + x * x * x * x * 131 + x * x * x * 757 + x * 853 + 1483) mod 9973;
b := (y * y * y * y * y * 269 + y * y * y * y * 379 + y * y * y * y * 467 + y * y * y * 569 + y * 659 + 3559) mod 9967;
Result:= a xor b;

x * x * x * x * 313 + x * x * x * x * 131

x * x * x * x * (313 + 131)