diff options
Diffstat (limited to 'board/cr50/dcrypto/fips_rand.h')
| -rw-r--r-- | board/cr50/dcrypto/fips_rand.h | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/board/cr50/dcrypto/fips_rand.h b/board/cr50/dcrypto/fips_rand.h index 10e44c7414..1010ad5e4d 100644 --- a/board/cr50/dcrypto/fips_rand.h +++ b/board/cr50/dcrypto/fips_rand.h @@ -18,6 +18,11 @@ extern "C" { #define TRNG_SAMPLE_BITS 1 +/** + * Probability of false positive in single APT/RCT test + * defined as 2^(-TRNG_TEST_ALPHA). + */ +#define TRNG_TEST_ALPHA 40 /** * TRNG Health Tests @@ -43,9 +48,14 @@ extern "C" { * (1) Repetition Count Test (RCT) NIST SP 800-90B 4.4.1 * Cut off value is computed as: * c = ceil(1 + (-log2 alpha)/H); - * alpha = 2^-50, H = 0.85; RCT_CUTOFF = CEIL(1+(50/0.85)) + * alpha = 2^-50, H = 0.8; RCT_CUTOFF = CEIL(1+(ALPHA/0.8)) */ -#define RCT_CUTOFF_SAMPLES 60 +#if TRNG_TEST_ALPHA == 40 +#define RCT_CUTOFF_SAMPLES 51 +#else +/* RCT cut off for TRNG_TEST_ALPHA == 30 */ +#define RCT_CUTOFF_SAMPLES 39 +#endif /** * Number of 32-bit words containing RCT_CUTOFF_SAMPLES samples @@ -66,10 +76,14 @@ extern "C" { #define APT_WINDOW_SIZE_NWORDS (BITS_TO_WORDS(APT_WINDOW_SIZE_BITS)) /** * Cut off value = CRITBINOM(W, power(2,(-H)),1-α). - * 692 = CRITBINOM(1024, power(2,(-0.85)), 1 - 2^(-50)) + * 698 = CRITBINOM(1024, power(2,(-0.8)), 1 - 2^(-40)) */ -#define APT_CUTOFF_SAMPLES 692 - +#if TRNG_TEST_ALPHA == 40 +#define APT_CUTOFF_SAMPLES 698 +#else +/* APT cut off for TRNG_TEST_ALPHA == 30 */ +#define APT_CUTOFF_SAMPLES 682 +#endif #ifdef __cplusplus } |