Merge branch 'fix/rng_entropy_mixing_with_rtc_timer' into 'master'

mahavirj · mahavirj · commit cde30c2407bb · 2025-09-11T12:01:39.000+05:30
fix(esp_hw_support): Fixed entropy mixing of RTC timer with RNG

See merge request espressif/esp-idf!41723
diff --git a/components/esp_hw_support/hw_random.c b/components/esp_hw_support/hw_random.c
@@ -78,7 +78,7 @@ uint32_t IRAM_ATTR esp_random(void)
             result ^= REG_READ(WDEV_RND_REG);
         } while (ccount - last_ccount < cpu_to_apb_freq_ratio * APB_CYCLE_WAIT_NUM);
         uint32_t current_rtc_timer_counter = (lp_timer_hal_get_cycle_count() & 0xFF);
-        result ^= ((result ^ current_rtc_timer_counter) & 0xFF) << (i * 8);
+        result ^= (current_rtc_timer_counter << (i * 8));
     }
 #else
     do {

Original file line number	Diff line number	Diff line change
`@@ -78,7 +78,7 @@ uint32_t IRAM_ATTR esp_random(void)`
`78`	`78`	`result ^= REG_READ(WDEV_RND_REG);`
`79`	`79`	`} while (ccount - last_ccount < cpu_to_apb_freq_ratio * APB_CYCLE_WAIT_NUM);`
`80`	`80`	`uint32_t current_rtc_timer_counter = (lp_timer_hal_get_cycle_count() & 0xFF);`
`81`		`- result ^= ((result ^ current_rtc_timer_counter) & 0xFF) << (i * 8);`
	`81`	`+ result ^= (current_rtc_timer_counter << (i * 8));`
`82`	`82`	`}`
`83`	`83`	`#else`
`84`	`84`	`do {`