diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32L0/entropy_hardware_poll.c b/hal/targets/hal/TARGET_STM/TARGET_STM32L0/trng_api.c
similarity index 63%
rename from hal/targets/hal/TARGET_STM/TARGET_STM32L0/entropy_hardware_poll.c
rename to hal/targets/hal/TARGET_STM/TARGET_STM32L0/trng_api.c
index 611a5e3ff1..c8fd7dbe5f 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32L0/entropy_hardware_poll.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32L0/trng_api.c
@@ -18,66 +18,63 @@
  *
  */
 
+#if defined(DEVICE_TRNG)
 
 #if defined (TARGET_STM32L052xx) || defined (TARGET_STM32L053xx) || defined (TARGET_STM32L062xx) ||  defined (TARGET_STM32L063xx) || \
     defined (TARGET_STM32L072xx) || defined (TARGET_STM32L073xx) || defined (TARGET_STM32L082xx) ||  defined (TARGET_STM32L083xx)
 
 #include <stdlib.h>
 #include "cmsis.h"
+#include "trng_api.h"
 
-/* RNG handler declaration */
-RNG_HandleTypeDef RngHandle;
-
-
-/** rng_get_byte
+/** trng_get_byte
  *  @brief Get one byte of entropy from the RNG, assuming it is up and running.
+ *  @param obj TRNG obj
  *  @param pointer to the hardware generated random byte.
  */
-static void rng_get_byte( unsigned char *byte )
+static void trng_get_byte(trng_t *obj, unsigned char *byte )
 {
-    *byte = (unsigned char)HAL_RNG_GetRandomNumber(&RngHandle);
+    *byte = (unsigned char)HAL_RNG_GetRandomNumber(&obj->handle);
 }
 
-
-/** mbedtls_hardware_poll
- *  @brief Get len bytes of entropy from the hardware RNG.
- *  @param data pointer will be NULL
- *  @param output pointer to the random generated bytes buffer
- *  @param len input is the requested length of bytes to be generated
- *  @param olen is the pointer to the length of bytes effectively generated
- *  @returns 0 if the generation went well. -1 in case of error
- */
-int mbedtls_hardware_poll( void *data, unsigned char *output, size_t len, size_t *olen )
+void trng_init(trng_t *obj)
 {
-    int ret;
-    ((void) data);
-
     /* RNG Peripheral clock enable */
     __HAL_RCC_RNG_CLK_ENABLE();
 
     /* Initialize RNG instance */
-    RngHandle.Instance = RNG;
-    HAL_RNG_Init(&RngHandle);
+    obj->handle.Instance = RNG;
+    HAL_RNG_Init(&obj->handle);
+
+}
+
+void trng_free(trng_t *obj)
+{
+    /*Disable the RNG peripheral */
+    HAL_RNG_DeInit(&obj->handle);
+    /* RNG Peripheral clock disable - assume we're the only users of RNG  */
+    __HAL_RCC_RNG_CLK_DISABLE();
+}
+
+int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
+{
+    int ret;
 
     /* Get Random byte */
-    for( uint32_t i = 0; i < len; i++ ){
-        rng_get_byte( output + i );
-
+    for( uint32_t i = 0; i < length; i++ ){
+        trng_get_byte(obj, output + i );
     }
-    *olen = len;
+
+    *output_length = length;
     /* Just be extra sure that we didn't do it wrong */
-    if( ( __HAL_RNG_GET_FLAG(&RngHandle, (RNG_FLAG_CECS|RNG_FLAG_SECS)) ) != 0 ) {
+    if( ( __HAL_RNG_GET_FLAG(&obj->handle, (RNG_FLAG_CECS | RNG_FLAG_SECS)) ) != 0 ) {
         ret = -1;
     } else {
         ret = 0;
     }
-    /*Disable the RNG peripheral */
-    HAL_RNG_DeInit(&RngHandle);
-    /* RNG Peripheral clock disable - assume we're the only users of RNG  */
-    __HAL_RCC_RNG_CLK_DISABLE();
-
 
     return( ret );
 }
 #endif /* STM32L073RZ */
 
+#endif
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32L4/entropy_hardware_poll.c b/hal/targets/hal/TARGET_STM/TARGET_STM32L4/trng_api.c
similarity index 63%
rename from hal/targets/hal/TARGET_STM/TARGET_STM32L4/entropy_hardware_poll.c
rename to hal/targets/hal/TARGET_STM/TARGET_STM32L4/trng_api.c
index e7a880f44b..64483b8f12 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32L4/entropy_hardware_poll.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32L4/trng_api.c
@@ -18,36 +18,24 @@
  *
  */
 
+#if defined(DEVICE_TRNG)
 
 #include <stdlib.h>
 #include "cmsis.h"
+#include "trng_api.h"
 
-/* RNG handler declaration */
-RNG_HandleTypeDef RngHandle;
-
-
-/** rng_get_byte
+/** trng_get_byte
  *  @brief Get one byte of entropy from the RNG, assuming it is up and running.
+ *  @param obj TRNG obj
  *  @param pointer to the hardware generated random byte.
  */
-static void rng_get_byte( unsigned char *byte )
+static void trng_get_byte(trng_t *obj, unsigned char *byte )
 {
-    *byte = (unsigned char)HAL_RNG_GetRandomNumber(&RngHandle);
+    *byte = (unsigned char)HAL_RNG_GetRandomNumber(&obj->handle);
 }
 
-
-/** mbedtls_hardware_poll
- *  @brief Get len bytes of entropy from the hardware RNG.
- *  @param data pointer will be NULL
- *  @param output pointer to the random generated bytes buffer
- *  @param len input is the requested length of bytes to be generated
- *  @param olen is the pointer to the length of bytes effectively generated
- *  @returns 0 if the generation went well. -1 in case of error
- */
-int mbedtls_hardware_poll( void *data, unsigned char *output, size_t len, size_t *olen )
+void trng_init(trng_t *obj)
 {
-    int ret;
-    ((void) data);
     RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
 
     /*Select PLLQ output as RNG clock source */
@@ -59,27 +47,38 @@ int mbedtls_hardware_poll( void *data, unsigned char *output, size_t len, size_t
     __HAL_RCC_RNG_CLK_ENABLE();
 
     /* Initialize RNG instance */
-    RngHandle.Instance = RNG;
-    HAL_RNG_Init(&RngHandle);
+    obj->handle.Instance = RNG;
+    HAL_RNG_Init(&obj->handle);
+
+}
+
+void trng_free(trng_t *obj)
+{
+    /*Disable the RNG peripheral */
+    HAL_RNG_DeInit(&obj->handle);
+    /* RNG Peripheral clock disable - assume we're the only users of RNG  */
+    __HAL_RCC_RNG_CLK_DISABLE();
+}
+
+int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
+{
+    int ret;
 
     /* Get Random byte */
-    for( uint32_t i = 0; i < len; i++ ){
-        rng_get_byte( output + i );
-
+    for( uint32_t i = 0; i < length; i++ ){
+        trng_get_byte(obj, output + i );
     }
-    *olen = len;
+
+    *output_length = length;
     /* Just be extra sure that we didn't do it wrong */
-    if( ( __HAL_RNG_GET_FLAG(&RngHandle, (RNG_FLAG_CECS|RNG_FLAG_SECS)) ) != 0 ) {
+    if( ( __HAL_RNG_GET_FLAG(&obj->handle, (RNG_FLAG_CECS | RNG_FLAG_SECS)) ) != 0 ) {
         ret = -1;
     } else {
         ret = 0;
     }
-    /*Disable the RNG peripheral */
-    HAL_RNG_DeInit(&RngHandle);
-    /* RNG Peripheral clock disable - assume we're the only users of RNG  */
-    __HAL_RCC_RNG_CLK_DISABLE();
 
     return( ret );
 }
 
 
+#endif
diff --git a/targets/TARGET_STM/TARGET_STM32F7/trng_api.c b/targets/TARGET_STM/TARGET_STM32F7/trng_api.c
index ef3595e9b1..f435798f36 100644
--- a/targets/TARGET_STM/TARGET_STM32F7/trng_api.c
+++ b/targets/TARGET_STM/TARGET_STM32F7/trng_api.c
@@ -26,6 +26,7 @@
 
 /** trng_get_byte
  *  @brief Get one byte of entropy from the RNG, assuming it is up and running.
+ *  @param obj TRNG obj
  *  @param pointer to the hardware generated random byte.
  */
 static void trng_get_byte(trng_t *obj, unsigned char *byte )
diff --git a/targets/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/objects.h b/targets/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/objects.h
index b464a5f2e7..3932d46128 100644
--- a/targets/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/objects.h
+++ b/targets/TARGET_STM/TARGET_STM32L0/TARGET_DISCO_L053C8/objects.h
@@ -84,6 +84,10 @@ struct i2c_s {
     I2CName  i2c;
 };
 
+struct trng_s {
+    RNG_HandleTypeDef handle;
+};
+
 #include "common_objects.h"
 #include "gpio_object.h"
 
diff --git a/targets/TARGET_STM/TARGET_STM32L4/TARGET_DISCO_L476VG/objects.h b/targets/TARGET_STM/TARGET_STM32L4/TARGET_DISCO_L476VG/objects.h
index 7f1ca3c87d..20556881d8 100644
--- a/targets/TARGET_STM/TARGET_STM32L4/TARGET_DISCO_L476VG/objects.h
+++ b/targets/TARGET_STM/TARGET_STM32L4/TARGET_DISCO_L476VG/objects.h
@@ -90,6 +90,10 @@ struct can_s {
     int index;
 };
 
+struct trng_s {
+    RNG_HandleTypeDef handle;
+};
+
 #include "common_objects.h"
 #include "gpio_object.h"
 
diff --git a/targets/TARGET_STM/TARGET_STM32L4/TARGET_NUCLEO_L432KC/objects.h b/targets/TARGET_STM/TARGET_STM32L4/TARGET_NUCLEO_L432KC/objects.h
index 3aa688ef3a..c3407b008d 100644
--- a/targets/TARGET_STM/TARGET_STM32L4/TARGET_NUCLEO_L432KC/objects.h
+++ b/targets/TARGET_STM/TARGET_STM32L4/TARGET_NUCLEO_L432KC/objects.h
@@ -90,6 +90,10 @@ struct can_s {
     int index;
 };
 
+struct trng_s {
+    RNG_HandleTypeDef handle;
+};
+
 #include "gpio_object.h"
 #include "common_objects.h"
 
diff --git a/targets/TARGET_STM/TARGET_STM32L4/TARGET_NUCLEO_L476RG/objects.h b/targets/TARGET_STM/TARGET_STM32L4/TARGET_NUCLEO_L476RG/objects.h
index 7f1ca3c87d..20556881d8 100644
--- a/targets/TARGET_STM/TARGET_STM32L4/TARGET_NUCLEO_L476RG/objects.h
+++ b/targets/TARGET_STM/TARGET_STM32L4/TARGET_NUCLEO_L476RG/objects.h
@@ -90,6 +90,10 @@ struct can_s {
     int index;
 };
 
+struct trng_s {
+    RNG_HandleTypeDef handle;
+};
+
 #include "common_objects.h"
 #include "gpio_object.h"
 
diff --git a/targets/targets.json b/targets/targets.json
index e5acb852cd..04372b25b9 100644
--- a/targets/targets.json
+++ b/targets/targets.json
@@ -920,6 +920,7 @@
         "inherits": ["Target"],
         "detect_code": ["0760"],
         "device_has": ["ANALOGIN", "ANALOGOUT", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SERIAL_ASYNCH", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES", "TRNG"],
+        "release_versions": ["2", "5"]
         "device_name": "STM32L073RZ"
     },
     "NUCLEO_L152RE": {
@@ -943,7 +944,7 @@
         "inherits": ["Target"],
         "detect_code": ["0770"],
         "device_has": ["ANALOGIN", "ANALOGOUT", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "CAN", "STDIO_MESSAGES", "TRNG"],
-
+        "release_versions": ["2", "5"]
         "device_name" : "STM32L432KC"
     },
     "NUCLEO_L476RG": {
@@ -955,6 +956,7 @@
         "inherits": ["Target"],
         "detect_code": ["0765"],
         "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES", "TRNG"],
+        "release_versions": ["2", "5"]
         "device_name": "stm32l476rg"
     },
     "STM32F3XX": {
@@ -1099,6 +1101,7 @@
         "supported_toolchains": ["ARM", "uARM", "IAR", "GCC_ARM"],
         "detect_code": ["0820"],
         "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES", "TRNG"],
+        "release_versions": ["2", "5"]
         "device_name": "stm32l476vg"
     },
     "MTS_MDOT_F405RG": {