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Bill Cox
2014-10-19 14:48:02 -04:00
parent 9a079fed74
commit 7632877b12
2 changed files with 36 additions and 52 deletions
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76
software/healthcheck.c
View File

@@ -28,7 +28,7 @@ confirmed.
#include <time.h>
#include "healthcheck.h"
#define INM_MIN_DATA 10000
#define INM_MIN_DATA 80000
#define INM_MIN_SAMPLE_SIZE 100
#define INM_ACCURACY 1.05
#define INM_MAX_SEQUENCE 20
@@ -38,7 +38,7 @@ confirmed.
static uint8_t inmN;
static uint32_t inmPrevBits;
static uint32_t inmNumBitsCounted, inmNumBitsSampled;
static uint32_t inmNumBitsSampled;
static uint32_t *inmOnes, *inmZeros;
static double inmK, inmExpectedEntropyPerBit;
// The total probability of generating the string of states we did is
@@ -63,7 +63,6 @@ void inmHealthCheckStop(void) {
// Reset the statistics.
static void resetStats(void) {
inmNumBitsSampled = 0;
inmNumBitsCounted = 0;
inmCurrentProbability = 1.0;
inmNumBitsOfEntropy = 0;
inmEntropyLevel = 0;
@@ -105,17 +104,20 @@ static void scaleStats(void) {
inmZeros[i] >>= 1;
inmOnes[i] >>= 1;
}
if(inmNumBitsSampled > 2*INM_MIN_DATA) {
inmNumBitsCounted = inmNumBitsCounted*(uint64_t)2*INM_MIN_DATA/inmNumBitsSampled;
inmNumBitsOfEntropy = inmNumBitsOfEntropy*(uint64_t)2*INM_MIN_DATA/inmNumBitsSampled;
inmNumBitsSampled = 2*INM_MIN_DATA;
}
}
// If running continuously, it is possible to start overflowing the 32-bit counters for
// zeros and ones. Check for this, and scale the stats if needed.
static void scaleEntropy(void) {
printf("Scaling entropy...\n");
inmNumBitsOfEntropy = inmNumBitsOfEntropy*(uint64_t)INM_MIN_DATA/(2*inmNumBitsSampled);
inmNumBitsSampled = INM_MIN_DATA/2;
}
// This should be called for each bit generated.
bool inmHealthCheckAddBit(bool bit) {
inmTotalBits++;
if((inmTotalBits & 0xfff) == 0) {
if((inmTotalBits & 0xffff) == 0) {
printf("Estimated entropy per bit: %f, estimated K: %f\n", inmHealthCheckEstimateEntropyPerBit(),
inmHealthCheckEstimateK());
}
@@ -141,28 +143,24 @@ bool inmHealthCheckAddBit(bool bit) {
}
}
}
if(inmOnes[inmPrevBits] > INM_MIN_SAMPLE_SIZE ||
inmZeros[inmPrevBits] > INM_MIN_SAMPLE_SIZE) {
uint32_t total = inmZeros[inmPrevBits] + inmOnes[inmPrevBits];
if(bit) {
if(inmOnes[inmPrevBits] != 0) {
inmCurrentProbability *= (double)inmOnes[inmPrevBits]/total;
}
} else {
if(inmZeros[inmPrevBits] != 0) {
inmCurrentProbability *= (double)inmZeros[inmPrevBits]/total;
}
uint32_t total = inmZeros[inmPrevBits] + inmOnes[inmPrevBits];
if(bit) {
if(inmOnes[inmPrevBits] != 0) {
inmCurrentProbability *= (double)inmOnes[inmPrevBits]/total;
}
while(inmCurrentProbability <= 0.5) {
inmCurrentProbability *= 2.0;
inmNumBitsOfEntropy++;
if(inmHealthCheckOkToUseData() && inmEntropyLevel < INM_MAX_ENTROPY) {
inmEntropyLevel++;
}
} else {
if(inmZeros[inmPrevBits] != 0) {
inmCurrentProbability *= (double)inmZeros[inmPrevBits]/total;
}
//printf("probability:%f\n", inmCurrentProbability);
inmNumBitsCounted++;
}
while(inmCurrentProbability <= 0.5) {
inmCurrentProbability *= 2.0;
inmNumBitsOfEntropy++;
if(inmHealthCheckOkToUseData() && inmEntropyLevel < INM_MAX_ENTROPY) {
inmEntropyLevel++;
}
}
//printf("probability:%f\n", inmCurrentProbability);
inmNumBitsSampled++;
if(bit) {
inmOnes[inmPrevBits]++;
@@ -175,24 +173,8 @@ bool inmHealthCheckAddBit(bool bit) {
scaleStats();
}
}
//printf("prevBits: %x\n", inmPrevBits);
if(inmNumBitsSampled < INM_MIN_DATA) {
return true; // Not enough data yet to test
}
if(inmNumBitsSampled == INM_MIN_DATA && inmNumBitsCounted < INM_MIN_DATA*0.99) {
// Wait until we have enough data to start measuring entropy
resetStats();
return true;
}
if(inmNumBitsSampled == INM_MIN_DATA) {
printf("Generated a total of %lu bits to initialize health check\n", inmTotalBits);
}
// Check the entropy is in line with expectations
uint32_t expectedEntropy = inmExpectedEntropyPerBit*inmNumBitsCounted;
if(inmNumBitsOfEntropy > expectedEntropy*INM_ACCURACY || inmNumBitsOfEntropy < expectedEntropy/INM_ACCURACY) {
printf("entropy:%u, expected entropy:%u, num bits counted:%u, num bits sampled:%u\n",
inmNumBitsOfEntropy, expectedEntropy, inmNumBitsCounted, inmNumBitsSampled);
return false;
scaleEntropy();
}
return true;
}
@@ -200,14 +182,14 @@ bool inmHealthCheckAddBit(bool bit) {
// Once we have enough samples, we know that entropyPerBit = log(K)/log(2), so
// K must be 2^entryopPerBit.
double inmHealthCheckEstimateK(void) {
double entropyPerBit = (double)inmNumBitsOfEntropy/inmNumBitsCounted;
double entropyPerBit = (double)inmNumBitsOfEntropy/inmNumBitsSampled;
return pow(2.0, entropyPerBit);
}
// Once we have enough samples, we know that entropyPerBit = log(K)/log(2), so
// K must be 2^entryopPerBit.
double inmHealthCheckEstimateEntropyPerBit(void) {
return (double)inmNumBitsOfEntropy/inmNumBitsCounted;
return (double)inmNumBitsOfEntropy/inmNumBitsSampled;
}
// Return true if the health checker has enough data to verify proper operation of the INM.

12
software/infnoise.c
View File

@@ -9,7 +9,9 @@
#include "KeccakF-1600-interface.h"
// Must be multiple of 64
#define BUFLEN 64
//#define BUFLEN 64
// The FT240X has a 512 byte buffer
#define BUFLEN 512
#define COMP1 1
#define COMP2 4
@@ -99,7 +101,7 @@ int main(int argc, char **argv)
// Initialize FTDI context
ftdi_init(&ftdic);
if(!inmHealthCheckStart(9, 1.82)) {
if(!inmHealthCheckStart(14, 1.82)) {
puts("Can't intialize health checker\n");
return 1;
}
@@ -114,7 +116,7 @@ int main(int argc, char **argv)
// Set high baud rate
int rc = 0;
//rc = ftdi_set_baudrate(&ftdic, 3000000);
rc = ftdi_set_baudrate(&ftdic, 3000000);
if(rc == -1) {
puts("Invalid baud rate\n");
return -1;
@@ -146,6 +148,7 @@ int main(int argc, char **argv)
//outBuf[BUFLEN-1] = 0;
while(true) {
/*
for(i = 0; i < BUFLEN; i++) {
if(ftdi_write_data(&ftdic, outBuf + i, 1) != 1) {
puts("USB write failed\n");
@@ -156,7 +159,7 @@ int main(int argc, char **argv)
return -1;
}
}
/*
*/
if(ftdi_write_data(&ftdic, outBuf, BUFLEN) != BUFLEN) {
puts("USB write failed\n");
return -1;
@@ -165,7 +168,6 @@ int main(int argc, char **argv)
puts("USB read failed\n");
return -1;
}
*/
uint8_t bytes[BUFLEN/8];
extractBytes(bytes, inBuf, raw);
//processBytes(keccakState, bytes, raw);