[xkor]

procedure RSAkeyDecode(var raw);
var
  ab: array[0..127] of Byte absolute raw;
  i:  Word;
  b:  Byte;
begin
  for i:=0 to $3f do ab[$40+i]:=ab[$40+i] xor ab[i];
  for i:=0 to $03 do ab[$0d+i]:=ab[$0d+i] xor ab[$34+i];
  for i:=0 to $3f do ab[i]:=ab[i] xor ab[$40+i];
  for i:=0 to $03 do begin
    b:=ab[i];
    ab[i]:=ab[$4d+i];
    ab[$4d+i]:=b;
  end;
end;

function RSAEncrypt_GMP(a, p: string; var rsakey): string; 
var
  sD:string;
  m,d,r: mpz_t;
  count: Integer;
begin
  RSAkeyDecode(rsakey);
  if length(a)>14 then setlength(a,14);
  while length(a)<14 do a:=a+#0;
  if length(p)>16 then setlength(p,16);
  while length(p)<16 do p:=p+#0;
  sD:=#$24#0#0+a+p+#0#0#0#0;
  mpz_init(m);
  mpz_import(m,128,1,1,0,0,rsakey);
  mpz_init(d);
  mpz_import(d,Length(sD),1,1,0,0,sD[1]);
  mpz_init(r);
  mpz_powm_ui(r,d,65537,m);
  count:=32;
  SetLength(Result,128);
  mpz_export(Result[1],count,1,4,1,0,r);
  mpz_clear(r);
  mpz_clear(d);
  mpz_clear(m);
end;

function RequestAuthLogin_c621(Login, Pasword: String; var rsakey; sessionID: Integer): string;
var
  Packet: TPacket;
  lpRSA: string;
  sock, i: Integer;
  strSizes: array[0..3] of Byte;
begin
  lpRSA:=RSAEncrypt_GMP(Login,Pasword,rsakey);

  with Packet do begin
    InitWrite;
    WriteB(0);                // Packet ID
    Write(lpRSA[1],128);      // Login, Password
    WriteD(sessionID);        // sessionID
    WriteD(0); WriteD(0); WriteD(0); WriteD(0);
    WriteB(8);
    WriteD(0); WriteD(0); WriteD(0); WriteD(0);
    WriteD(0); WriteD(0); WriteH(0);
    AddChecksum(data[3],160);
    Result:=data;
  end;
end;