Problem - Kevin Tafuro

#define FIPS_POKER_HIBOUND 57.4
int spc_fips_poker(unsigned char data[FIPS_NUMBYTES]) {
int i;
long counts[16] = {0,}, sum = 0;
double result;
for (i = 0; i < FIPS_NUMBYTES; i++) {
counts[data[i] & 0xf]++;
counts[data[i] >> 4]++;
}
for (i = 0; i < 16; i++)
sum += (counts[i] * counts[i]);
result = (16.0 / 5000) * (double)sum - 5000.0;
return (result > FIPS_POKER_LOBOUND && result < FIPS_POKER_HIBOUND);
}
The third and fourth FIPS 140-1 statistical tests are implemented as follows to run in
parallel in a single routine. The third test, the “Runs” test, goes through the data
stream and finds all the “runs” of consecutive bits that are identical. The test then
counts the maximum length of each run. That is, if there are three consecutive zeros
starting at the first position, that’s one run of length three, but it doesn’t count as
any runs of length two or any runs of length one. Runs that are longer than six bits
are counted as a six-bit run. At the end, for each length of run, the count for consecutive
zeros of that run length and the count for consecutive ones are examined. If
either fails to fall within a specified range, the test fails. If all of the results are in an
appropriate range for the run length in question, the test passes.
The fourth test, the “Long Runs” test, also calculates runs of bits. The test looks for
runs of 34 bits or longer. Any such runs cause the test to fail; otherwise, it succeeds.
#define FIPS_NUMBYTES 2500
#define FIPS_LONGRUN 34
#define FIPS_RUNS_1_LO 2267
#define FIPS_RUNS_1_HI 2733
#define FIPS_RUNS_2_LO 1079
#define FIPS_RUNS_2_HI 1421
#define FIPS_RUNS_3_LO 502
#define FIPS_RUNS_3_HI 748
#define FIPS_RUNS_4_LO 223
#define FIPS_RUNS_4_HI 402
#define FIPS_RUNS_5_LO 90
#define FIPS_RUNS_5_HI 223
#define FIPS_RUNS_6_LO 90
#define FIPS_RUNS_6_HI 223
/* Perform both the "Runs" test and the "Long Run" test */
int spc_fips_runs(unsigned char data[FIPS_NUMBYTES]) {
/* We allow a zero-length run size, mainly just to keep the array indexing less
* confusing. It also allows us to set cur_val arbitrarily below (if the first
* bit of the stream is a 1, then runs[0] will be 1; otherwise, it will be 0).
*/
int runs[2][7] = {{0,},{0,}};
618 | Chapter 11: Random Numbers
This is the Title of the Book, eMatter Edition
Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.