#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
typedef unsigned long int WORD; /* Should be 32-bit = 4 bytes */
#define w 32 /* word size in bits */
#define r 12 /* number of rounds */
#define b 16 /* number of bytes in key */
#define c 4 /* number words in key */
/* c = max(1,ceil(8*b/w)) */
#define t 26 /* size of table S = 2*(r+1) words */
WORD S [t],L[c]; /* expanded key table */
WORD P = 0xb7e15163, Q = 0x9e3779b9; /* magic constants */
/* Rotation operators. x must be unsigned, to get logical right shift*/
#define ROTL(x,y) (((x)<<(y&(w-1))) | ((x)>>(w-(y&(w-1)))))
#define ROTR(x,y) (((x)>>(y&(w-1))) | ((x)<<(w-(y&(w-1)))))
void RC5_DECRYPT(WORD *ct, WORD *pt) /* 2 WORD input ct/output pt */
{ WORD i, B=ct[1], A=ct[0];
for (i=r; i>0; i--)
{ B = ROTR(B-S [2*i+1],A)^A;
A = ROTR(A-S [2*i],B)^B;
}
pt [1] = B-S [1] ;pt [0] = A-S [0];
}
void RC5_SETUP(unsigned char *K) /* secret input key K 0...b-1] */
{ WORD i, j, k, u=w/8, A, B, L [c];
/* Initialize L, then S, then mix key into S */
for (i=b-1,L[c-1]=0; i!=-1; i--) L[i/u] = (L[i/u]<<8)+K[ i];
for (S [0]=P,i=1; i<t; i++) S [i] = S [i-1]+Q;
for (A=B=i=j=k=0; k<3*t; k++,i=(i+1)%t,j=(j+1)%c) /* 3*t > 3*c */
{ A = S[i] = ROTL(S [i]+(A+B),3);
B = L[j] = ROTL(L[j]+(A+B),(A+B));
}
}
void printword(WORD A)
{ WORD k;
for (k=0 ;k<w; k+=8) printf("%02.2lX",(A>>k)&0xFF);
}
int main()
{ WORD i, j, k, pt [2], pt2 [2], ct [2] = {0,0};
unsigned char key[b];
ofstream out("cpt.txt");
ifstream in("key.txt");
if(!in)
{
cout << "Cannot open file.\n";
return 1;
}
if(!out)
{
cout << "Cannot open file.\n";
return 1;
}
key="111111000001111";
RC5_SETUP(key);
ct[0]=2185970173;
ct[1]=3384368406;
for (i=1;i<2;i++)
{
RC5_DECRYPT(ct,pt2);
printf("\n plaintext "); printword(pt [0]); printword(pt[1]);
}
return 0;
}
When I compile this code, I get two warnings and also an error saying that I can't assign a char value to my character array. Why is that?
