Cryptography Reference
In-Depth Information
27
double thresh, trust1, trust, min, delta, expkappa, Nd,
28
kappa[2*MAXPERIOD], patt[256], frequ[256];
29
FILE *fp;
||
30
if(argc != 2
(fp = fopen(argv[1], "r")) == NULL)
31
{perror(argv[1]); exit(1);}
32
/* read distribution pattern */
33
expkappa = thresh = 0.;
34
for(n=0; n < 256; ++n)
35
{
36
if(fscanf(fp, "%d %le
\
n", &c, patt+n) != 2
||
c!=n
||
patt[n] < 0.)
37
{
38
fprintf(stderr, "error in pattern file, line %d: %d %g
\
n",
39
n, c, patt[n]);
40
exit(1);
41
}
42
expkappa += patt[n]*patt[n];
43
if(patt[n] > thresh)
44
{
45
indx = n; thresh = patt[n];
46
}
47
}
48
thresh *= THRESH;
printf("expected index of coincidence: %.2f%%
\
n", expkappa*100.);
49
50
/* read file probe */
51
N = fread(buf, 1, MAXLEN, stdin);
Figure 3.13:
(
continued
)
