/* 
   Unoptimized test implementation of SKIPJACK algorithm 
   Panu Rissanen <bande@lut.fi> 960624

   SKIPJACK and KEA Algorithm Specifications 
   Version 2.0 
   29 May 1998
*/

const unsigned char ftable[256] = { 
0xa3,0xd7,0x09,0x83,0xf8,0x48,0xf6,0xf4,0xb3,0x21,0x15,0x78,0x99,0xb1,0xaf,0xf9,
0xe7,0x2d,0x4d,0x8a,0xce,0x4c,0xca,0x2e,0x52,0x95,0xd9,0x1e,0x4e,0x38,0x44,0x28,
0x0a,0xdf,0x02,0xa0,0x17,0xf1,0x60,0x68,0x12,0xb7,0x7a,0xc3,0xe9,0xfa,0x3d,0x53,
0x96,0x84,0x6b,0xba,0xf2,0x63,0x9a,0x19,0x7c,0xae,0xe5,0xf5,0xf7,0x16,0x6a,0xa2,
0x39,0xb6,0x7b,0x0f,0xc1,0x93,0x81,0x1b,0xee,0xb4,0x1a,0xea,0xd0,0x91,0x2f,0xb8,
0x55,0xb9,0xda,0x85,0x3f,0x41,0xbf,0xe0,0x5a,0x58,0x80,0x5f,0x66,0x0b,0xd8,0x90,
0x35,0xd5,0xc0,0xa7,0x33,0x06,0x65,0x69,0x45,0x00,0x94,0x56,0x6d,0x98,0x9b,0x76,
0x97,0xfc,0xb2,0xc2,0xb0,0xfe,0xdb,0x20,0xe1,0xeb,0xd6,0xe4,0xdd,0x47,0x4a,0x1d,
0x42,0xed,0x9e,0x6e,0x49,0x3c,0xcd,0x43,0x27,0xd2,0x07,0xd4,0xde,0xc7,0x67,0x18,
0x89,0xcb,0x30,0x1f,0x8d,0xc6,0x8f,0xaa,0xc8,0x74,0xdc,0xc9,0x5d,0x5c,0x31,0xa4,
0x70,0x88,0x61,0x2c,0x9f,0x0d,0x2b,0x87,0x50,0x82,0x54,0x64,0x26,0x7d,0x03,0x40,
0x34,0x4b,0x1c,0x73,0xd1,0xc4,0xfd,0x3b,0xcc,0xfb,0x7f,0xab,0xe6,0x3e,0x5b,0xa5,
0xad,0x04,0x23,0x9c,0x14,0x51,0x22,0xf0,0x29,0x79,0x71,0x7e,0xff,0x8c,0x0e,0xe2,
0x0c,0xef,0xbc,0x72,0x75,0x6f,0x37,0xa1,0xec,0xd3,0x8e,0x62,0x8b,0x86,0x10,0xe8,
0x08,0x77,0x11,0xbe,0x92,0x4f,0x24,0xc5,0x32,0x36,0x9d,0xcf,0xf3,0xa6,0xbb,0xac,
0x5e,0x6c,0xa9,0x13,0x57,0x25,0xb5,0xe3,0xbd,0xa8,0x3a,0x01,0x05,0x59,0x2a,0x46
};

int g(unsigned char *key, int k, int w) {
unsigned char g1,g2,g3,g4,g5,g6;

  g1=(w>>8)&0xff;
  g2=w&0xff;

  g3=ftable[g2^key[(4*k)%10]]^g1;
  g4=ftable[g3^key[(4*k+1)%10]]^g2;
  g5=ftable[g4^key[(4*k+2)%10]]^g3;
  g6=ftable[g5^key[(4*k+3)%10]]^g4;

  return ((g5<<8)+g6);
}

#include <stdio.h>
int main() {
  unsigned char in[8] = { 0x33,0x22,0x11,0x00,0xdd,0xcc,0xbb,0xaa };
  unsigned char key[10] = { 0x00,0x99,0x88,0x77,0x66,0x55,0x44,0x33,0x22,0x11 };
  unsigned int w1,w2,w3,w4,tmp;
  int t,i;
  int k=0;

  w1=(in[0]<<8)+in[1];
  w2=(in[2]<<8)+in[3];
  w3=(in[4]<<8)+in[5];
  w4=(in[6]<<8)+in[7];

  printf("    w1  w2   w3  w4\n   -----------------\n");

  for(t=0;t<2;t++) {
    for(i=0;i<8;i++) {
      printf("%2d %04x%04x %04x%04x\n",k,w1,w2,w3,w4);
      tmp=w4;
      w4=w3;
      w3=w2;
      w2=g(key,k,w1);
      w1=g(key,k,w1)^tmp^(k+1);
      k++;
    }

    for(i=0;i<8;i++) {
      printf("%2d %04x%04x %04x%04x\n",k,w1,w2,w3,w4);
      tmp=w4;
      w4=w3;
      w3=w1^w2^(k+1);
      w2=g(key,k,w1);
      w1=tmp;
      k++;
    }
  }
  printf("%2d %04x%04x %04x%04x\n",k,w1,w2,w3,w4);
  return 0;
}