Fisrt completed USB key works

README.md

@@ -18,6 +18,11 @@ estimation of bits added to an entropy pool or cryptographic hash function.
 
 ### The Eagle open-source boards work!
 
+Here's the first completed Infinite Noise USB key.  This is what I would offer on Tindie
+if needed to get the INM concept out there.
+
+![Picture of Infinite Noise USB key](images/infnoise_key.jpg?raw=true "Infinite Noise USB key")
+
 Here's the first three boards from OSH Park.  They work _exactly_ as predicted.  They all
 generate 300,000 bits per second, resulting in 259,000 bits of entropy per second.
 

software/Makefile

@@ -1,7 +1,8 @@
 all: infnoise infnoise-v1 healthcheck findlongest
 
 infnoise: infnoise.c infnoise.h healthcheck.c writeentropy.c Keccak/KeccakF-1600-reference.c Keccak/brg_endian.h
-	gcc -Wall -std=c11 -O3 -m64 -march=native -I Keccak -o infnoise infnoise.c healthcheck.c writeentropy.c Keccak/KeccakF-1600-reference.c -lftdi -lm
+	#gcc -Wall -std=c11 -O3 -m64 -march=native -I Keccak -o infnoise infnoise.c healthcheck.c writeentropy.c Keccak/KeccakF-1600-reference.c -lftdi -lm
+	gcc -Wall -std=c11 -g -m64 -march=native -I Keccak -o infnoise infnoise.c healthcheck.c writeentropy.c Keccak/KeccakF-1600-reference.c -lftdi -lm
 
 infnoise-v1: infnoise.c infnoise.h healthcheck.c writeentropy.c Keccak/KeccakF-1600-reference.c Keccak/brg_endian.h
 	gcc -Wall -std=c11 -O3 -m64 -march=native -DVERSION1 -I Keccak -o infnoise-v1 infnoise.c healthcheck.c writeentropy.c Keccak/KeccakF-1600-reference.c -lftdi -lm

software/healthcheck.c

@@ -28,18 +28,16 @@ confirmed.
 
 #define INM_MIN_DATA 80000
 #define INM_MIN_SAMPLE_SIZE 100
-#define INM_ACCURACY 1.02
 #define INM_MAX_SEQUENCE 20
 #define INM_MAX_COUNT (1 << 14)
-// Matches the Keccac sponge size
-#define INM_MAX_ENTROPY 1600
+
+double inmK, inmExpectedEntropyPerBit;
 
 static uint8_t inmN;
 static uint32_t inmPrevBits;
 static uint32_t inmNumBitsSampled;
 static uint32_t *inmOnesEven, *inmZerosEven;
 static uint32_t *inmOnesOdd, *inmZerosOdd;
-static double inmK, inmExpectedEntropyPerBit;
 // The total probability of generating the string of states we did is
 // 1/(2^inmNumBitsOfEntropy * inmCurrentProbability).
 static uint32_t inmNumBitsOfEntropy;
@@ -214,7 +212,7 @@ bool inmHealthCheckAddBit(bool evenBit, bool oddBit, bool even) {
     while(inmCurrentProbability <= 0.5) {
         inmCurrentProbability *= 2.0;
         inmNumBitsOfEntropy++;
-        if(inmHealthCheckOkToUseData() && inmEntropyLevel < INM_MAX_ENTROPY) {
+        if(inmHealthCheckOkToUseData()) {
             inmEntropyLevel++;
         }
     }

software/infnoise.c

@@ -21,7 +21,8 @@
 #define SWEN1 4
 #define SWEN2 1
 #else
-#define DESIGN_K 1.736
+#define DESIGN_K 1.82
+//#define DESIGN_K 1.736
 #define COMP1 1
 #define COMP2 4
 #define SWEN1 2
@@ -62,9 +63,12 @@ static uint32_t extractBytes(uint8_t *bytes, uint8_t *inBuf, bool raw) {
     return inmGetEntropyLevel();
 }
 
-// Write the bytes to either stdout, or /dev/random.  Cut the entropy estimate in half to
-// be conservative.
+// Write the bytes to either stdout, or /dev/random.  Use the lower of the measured
+// entropy and the provable lower bound on average entropy.
 static void outputBytes(uint8_t *bytes, uint32_t length, uint32_t entropy, bool writeDevRandom) {
+    if(entropy > inmExpectedEntropyPerBit/INM_ACCURACY) {
+        entropy = inmExpectedEntropyPerBit/INM_ACCURACY;
+    }
     if(!writeDevRandom) {
         if(fwrite(bytes, 1, length, stdout) != length) {
             fputs("Unable to write output from Infinite Noise Multiplier\n", stderr);
@@ -103,8 +107,7 @@ static void Squeeze(uint8_t *keccakState, uint8_t *dataOut, uint32_t length) {
 }
 
 // Send the new bytes through the health checker and also into the Keccak sponge.
-// Output bytes from the sponge only if the health checker says it's OK, and only
-// output half the entropy we get from the INM, just to be paranoid.
+// Output bytes from the sponge only if the health checker says it's OK
 static void processBytes(uint8_t *keccakState, uint8_t *bytes, uint32_t entropy, bool raw, bool writeDevRandom) {
     if(raw) {
         // In raw mode, we just output raw data from the INM.
@@ -208,7 +211,7 @@ int main(int argc, char **argv)
     char *message;
     if(!initializeUSB(&ftdic, &message)) {
         // Sometimes have to do it twice - not sure why
-        ftdi_usb_close(&ftdic);
+        //ftdi_usb_close(&ftdic);
         if(!initializeUSB(&ftdic, &message)) {
             fputs(message, stderr);
             return 1;

software/infnoise.h

@@ -1,6 +1,9 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+// Required accuracy of estimated vs measured entropy in health monitor
+#define INM_ACCURACY 1.02
+
 bool inmHealthCheckStart(uint8_t N, double K, bool debug);
 void inmHealthCheckStop(void);
 bool inmHealthCheckAddBit(bool evenBit, bool oddBit, bool even);
@@ -13,3 +16,5 @@ bool inmEntropyOnTarget(uint32_t entropy, uint32_t bits);
 void inmWriteEntropyStart(uint32_t bufLen, bool debug);
 void inmWriteEntropyToPool(uint8_t *bytes, uint32_t length, uint32_t entropy);
 void inmWaitForPoolToHaveRoom(void);
+
+extern double inmK, inmExpectedEntropyPerBit;