updating crypto/rand to use Flipper Zero specific hardware RNG

crypto/rand.c

@@ -21,12 +21,19 @@
  * OTHER DEALINGS IN THE SOFTWARE.
  */
 
+// NOTE:
+// random32() and random_buffer() have been replaced in this implementation
+// with Flipper Zero specific code. The original code is commented out below.
+
 #include "rand.h"
 
+// Flipper Zero RNG code:
+#include <furi_hal_random.h>
+
 #ifndef RAND_PLATFORM_INDEPENDENT
 
-#pragma message( \
-    "NOT SUITABLE FOR PRODUCTION USE! Replace random32() function with your own secure code.")
+// Original code:
+// #pragma message("NOT SUITABLE FOR PRODUCTION USE! Replace random32() function with your own secure code.")
 
 // The following code is not supposed to be used in a production environment.
 // It's included only to make the library testable.
@@ -41,11 +48,22 @@ static uint32_t seed = 0;
 
 void random_reseed(const uint32_t value) { seed = value; }
 
+// Original code:
+// uint32_t random32(void) {
+//   // Linear congruential generator from Numerical Recipes
+//   // https://en.wikipedia.org/wiki/Linear_congruential_generator
+//   seed = 1664525 * seed + 1013904223;
+//   return seed;
+// }
+
+// Flipper Zero RNG code:
 uint32_t random32(void) {
-  // Linear congruential generator from Numerical Recipes
-  // https://en.wikipedia.org/wiki/Linear_congruential_generator
-  seed = 1664525 * seed + 1013904223;
-  return seed;
+  return furi_hal_random_get();
+}
+
+// Flipper Zero RNG code:
+void random_buffer(uint8_t *buf, size_t len) {
+  furi_hal_random_fill_buf(buf, len);
 }
 
 #endif /* RAND_PLATFORM_INDEPENDENT */
@@ -54,15 +72,16 @@ uint32_t random32(void) {
 // The following code is platform independent
 //
 
-void __attribute__((weak)) random_buffer(uint8_t *buf, size_t len) {
-  uint32_t r = 0;
-  for (size_t i = 0; i < len; i++) {
-    if (i % 4 == 0) {
-      r = random32();
-    }
-    buf[i] = (r >> ((i % 4) * 8)) & 0xFF;
-  }
-}
+// Original code:
+// void __attribute__((weak)) random_buffer(uint8_t *buf, size_t len) {
+//   uint32_t r = 0;
+//   for (size_t i = 0; i < len; i++) {
+//     if (i % 4 == 0) {
+//       r = random32();
+//     }
+//     buf[i] = (r >> ((i % 4) * 8)) & 0xFF;
+//   }
+// }
 
 uint32_t random_uniform(uint32_t n) {
   uint32_t x = 0, max = 0xFFFFFFFF - (0xFFFFFFFF % n);