#define NROUNDS 32

#define substLong(t) ( (uint)SubstTable20[(uint)t&255] | \

           ((uint)SubstTable20[(int)(t>> 8)&255]<< 8) | \

           ((uint)SubstTable20[(int)(t>>16)&255]<<16) | \

           ((uint)SubstTable20[(int)(t>>24)&255]<<24) )

static byte InitSubstTable20[256]={

  215, 19,149, 35, 73,197,192,205,249, 28, 16,119, 48,221,  2, 42,

  232,  1,177,233, 14, 88,219, 25,223,195,244, 90, 87,239,153,137,

  255,199,147, 70, 92, 66,246, 13,216, 40, 62, 29,217,230, 86,  6,

   71, 24,171,196,101,113,218,123, 93, 91,163,178,202, 67, 44,235,

  107,250, 75,234, 49,167,125,211, 83,114,157,144, 32,193,143, 36,

  158,124,247,187, 89,214,141, 47,121,228, 61,130,213,194,174,251,

   97,110, 54,229,115, 57,152, 94,105,243,212, 55,209,245, 63, 11,

  164,200, 31,156, 81,176,227, 21, 76, 99,139,188,127, 17,248, 51,

  207,120,189,210,  8,226, 41, 72,183,203,135,165,166, 60, 98,  7,

  122, 38,155,170, 69,172,252,238, 39,134, 59,128,236, 27,240, 80,

  131,  3, 85,206,145, 79,154,142,159,220,201,133, 74, 64, 20,129,

  224,185,138,103,173,182, 43, 34,254, 82,198,151,231,180, 58, 10,

  118, 26,102, 12, 50,132, 22,191,136,111,162,179, 45,  4,148,108,

  161, 56, 78,126,242,222, 15,175,146, 23, 33,241,181,190, 77,225,

    0, 46,169,186, 68, 95,237, 65, 53,208,253,168,  9, 18,100, 52,

  116,184,160, 96,109, 37, 30,106,140,104,150,  5,204,117,112, 84

};

void CryptData::SetKey20(const char *Password)

{

  InitCRC32(CRCTab);

  char Psw[MAXPASSWORD];

  strncpyz(Psw,Password,ASIZE(Psw)); // We'll need to modify it below.

  size_t PswLength=strlen(Psw);

  Key20[0]=0xD3A3B879L;

  Key20[1]=0x3F6D12F7L;

  Key20[2]=0x7515A235L;

  Key20[3]=0xA4E7F123L;

  memcpy(SubstTable20,InitSubstTable20,sizeof(SubstTable20));

  for (uint J=0;J<256;J++)

    for (size_t I=0;I<PswLength;I+=2)

    {

      uint N1=(byte)CRCTab [ (byte(Password[I])   - J) &0xff];

      uint N2=(byte)CRCTab [ (byte(Password[I+1]) + J) &0xff];

      for (int K=1;N1!=N2;N1=(N1+1)&0xff,K++)

        Swap20(&SubstTable20[N1],&SubstTable20[(N1+I+K)&0xff]);

    }

  // Incomplete last block of password must be zero padded.

  if ((PswLength & CRYPT_BLOCK_MASK)!=0)

    for (size_t I=PswLength;I<=(PswLength|CRYPT_BLOCK_MASK);I++)

       Psw[I]=0;

  for (size_t I=0;I<PswLength;I+=CRYPT_BLOCK_SIZE)

    EncryptBlock20((byte *)Psw+I);

}

void CryptData::EncryptBlock20(byte *Buf)

{

  uint A,B,C,D,T,TA,TB;

  A=RawGet4(Buf+0)^Key20[0];

  B=RawGet4(Buf+4)^Key20[1];

  C=RawGet4(Buf+8)^Key20[2];

  D=RawGet4(Buf+12)^Key20[3];

  for(int I=0;I<NROUNDS;I++)

  {

    T=((C+rotls(D,11,32))^Key20[I&3]);

    TA=A^substLong(T);

    T=((D^rotls(C,17,32))+Key20[I&3]);

    TB=B^substLong(T);

    A=C;

    B=D;

    C=TA;

    D=TB;

  }

  RawPut4(C^Key20[0],Buf+0);

  RawPut4(D^Key20[1],Buf+4);

  RawPut4(A^Key20[2],Buf+8);

  RawPut4(B^Key20[3],Buf+12);

  UpdKeys20(Buf);

}

void CryptData::DecryptBlock20(byte *Buf)

{

  byte InBuf[16];

  uint A,B,C,D,T,TA,TB;

  A=RawGet4(Buf+0)^Key20[0];

  B=RawGet4(Buf+4)^Key20[1];

  C=RawGet4(Buf+8)^Key20[2];

  D=RawGet4(Buf+12)^Key20[3];

  memcpy(InBuf,Buf,sizeof(InBuf));

  for(int I=NROUNDS-1;I>=0;I--)

  {

    T=((C+rotls(D,11,32))^Key20[I&3]);

    TA=A^substLong(T);

    T=((D^rotls(C,17,32))+Key20[I&3]);

    TB=B^substLong(T);

    A=C;

    B=D;

    C=TA;

    D=TB;

  }

  RawPut4(C^Key20[0],Buf+0);

  RawPut4(D^Key20[1],Buf+4);

  RawPut4(A^Key20[2],Buf+8);

  RawPut4(B^Key20[3],Buf+12);

  UpdKeys20(InBuf);

}

void CryptData::UpdKeys20(byte *Buf)

{

  for (int I=0;I<16;I+=4)

  {

    Key20[0]^=CRCTab[Buf[I]];

    Key20[1]^=CRCTab[Buf[I+1]];

    Key20[2]^=CRCTab[Buf[I+2]];

    Key20[3]^=CRCTab[Buf[I+3]];

  }

}

void CryptData::Swap20(byte *Ch1,byte *Ch2)

{

  byte Ch=*Ch1;

  *Ch1=*Ch2;

  *Ch2=Ch;

}