#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;
 }