defined seeded-rand fns using hmac

include/crypto.h

@@ -25,6 +25,8 @@ extern "C" {
 
 #include <sys/types.h>
 
+#include <why2/flags.h>
+
 //MACROS
 #define WHY2_SUM_SEGMENT_SIZE 32 //SEGMENT SIZE FOR CALCULATING SUM
 #define WHY2_SUM_BASE_PRIME 31 //PRIME FOR SUM BASE
@@ -35,7 +37,9 @@ extern "C" {
 
 //FUNCTIONS
 unsigned long long why2_sum_segment(char *input); //CALCULATE SUM++ FOR input; USED FOR PADDING SEED
-ssize_t why2_random(void *dest, size_t size); //WRITE CRYPTO-SECURE RANDOM NUMBER INTO dest
+why2_bool why2_random(void *dest, size_t size); //WRITE CRYPTO-SECURE RANDOM NUMBER INTO dest
+void why2_seed_random(unsigned long seed); //SEED why2_seeded_random OUTPUT
+int why2_seeded_random(); //GENERATE RANDOM NUMBER BASED ON SEED PASSED IN why2_seed_random
 
 #ifdef __cplusplus
 }

src/core/lib/decrypter.c

@@ -189,13 +189,13 @@ why2_output_flags why2_decrypt_text(char *text, char *key)
         }
 
         //OBTAIN SEED FROM key_new
-        srand(why2_sum_segment(key_new));
+        why2_seed_random(why2_sum_segment(key_new));
 
         //GET RANDOM SEQUENCE USED IN ENCRYPTION
         why2_list_t random_sequence = WHY2_LIST_EMPTY;
         for (unsigned long i = 0; i < why2_get_flags().padding; i++)
         {
-            int rand_buffer = rand();
+            int rand_buffer = why2_seeded_random();
             why2_list_push(&random_sequence, &rand_buffer, sizeof(int)); //ADD
         }
         why2_list_reverse(&random_sequence, sizeof(int)); //REVERSE

src/core/lib/encrypter.c

@@ -92,12 +92,12 @@ why2_output_flags why2_encrypt_text(char *text, char *key)
         }
 
         //OBTAIN SEED FROM key_new
-        srand(why2_sum_segment(key_new));
+        why2_seed_random(why2_sum_segment(key_new));
 
         //ADD PADDING TO split_text LIST
         for (unsigned long i = 0; i < why2_get_flags().padding; i++)
         {
-            unsigned long random_position = (unsigned long) (rand() % (why2_list_get_size(&split_text))); //GET RANDOM POSITION
+            unsigned long random_position = (unsigned long) (why2_seeded_random() % (why2_list_get_size(&split_text))); //GET RANDOM POSITION
 
             char random_char = 0;
             for (int j = 0; j < WHY2_PADDING_NONZERO_TRIES && random_char == 0 ; j++) //GET RANDOM (EXCLUDING 0)

src/core/lib/utils/crypto.c

@@ -18,11 +18,27 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #include <why2/crypto.h>
 
+#include <stdlib.h>
 #include <string.h>
 #include <math.h>
 #include <sys/types.h>
 #include <sys/random.h>
 
+#include <openssl/rand.h>
+#include <openssl/hmac.h>
+
+#include <why2/flags.h>
+
+typedef struct
+{
+    unsigned long seed; //DA SEED
+    unsigned long counter; //COUNTER FOR DETERMINISTIC OUTPUT
+} PRNG_CTX; //GENERATOR
+
+//LOCAL
+PRNG_CTX generator = { 0, 0 }; //SEEDED RANDOM GENERATOR
+
+//GLOBAL
 unsigned long long why2_sum_segment(char *input) //THE OUTPUT IS GOING TO GROW A LOT WITH LONG input, BUT IT SHOULDN'T BE A BIG PROBLEM. I TESTED FOR OVERFLOWS UP TO 4096-CHAR input AND ONLY GOT TO (14*10^(-7))% OF FULL ULL RANGE LMAO
 {
     unsigned long input_size = strlen(input);
@@ -47,7 +63,39 @@ unsigned long long why2_sum_segment(char *input) //THE OUTPUT IS GOING TO GROW A
     return output;
 }
 
-ssize_t why2_random(void *dest, size_t size)
+why2_bool why2_random(void *dest, size_t size)
 {
-    return getrandom(dest, size, GRND_NONBLOCK);
+    return RAND_bytes((unsigned char*) dest, size) == 1;
+}
+
+void why2_seed_random(unsigned long seed)
+{
+    memset(&generator, 0, sizeof(PRNG_CTX)); //INIT GENERATOR
+    memcpy(&(generator.seed), &seed, sizeof(generator.seed)); //COPY SEED
+    generator.counter = 0; //INIT COUNTER
+}
+
+int why2_seeded_random()
+{
+    int output;
+    unsigned char counter_bytes[4];
+    unsigned char hmac_output[EVP_MAX_MD_SIZE];
+    unsigned int hmac_len;
+
+    //CONVERT COUNTER TO BYTES
+    counter_bytes[0] = (generator.counter >> 24) & 0xFF;
+    counter_bytes[1] = (generator.counter >> 16) & 0xFF;
+    counter_bytes[2] = (generator.counter >> 8) & 0xFF;
+    counter_bytes[3] = generator.counter & 0xFF;
+
+    //HMAC (seed || counter)
+    HMAC(EVP_sha256(), &(generator.seed), sizeof(generator.seed), counter_bytes, sizeof(counter_bytes), hmac_output, &hmac_len);
+
+    //USE THE FIRST 4 BYTES OF THE HMAC OUTPUT AS DETERMINISTIC RANDOM INTEGER
+    memcpy(&output, hmac_output, sizeof(output));
+
+    //INCREMENT COUNTER
+    generator.counter++;
+
+    return output;
 }

src/core/lib/utils/misc.c

@@ -438,7 +438,7 @@ char *why2_generate_key(int key_length)
     for (int i = 0; i < key_length; i++)
     {
         //GET RANDOM NUMBER
-        if (why2_random(&random_buffer, sizeof(unsigned int)) == -1) why2_die("getrandom fn failed!");
+        if (!why2_random(&random_buffer, sizeof(unsigned int))) why2_die("getrandom fn failed!");
 
         //SET numberBuffer TO RANDOM NUMBER BETWEEN 0 AND 52
         number_buffer = (random_buffer % 52) + 1;