diff --git a/drivers/entropy/entropy_nrf5.c b/drivers/entropy/entropy_nrf5.c
index 8febcfacb15..2f04bc06a37 100644
--- a/drivers/entropy/entropy_nrf5.c
+++ b/drivers/entropy/entropy_nrf5.c
@@ -116,10 +116,6 @@ static int random_byte_get(void)
 	return retval;
 }
 
-#pragma GCC push_options
-#if defined(CONFIG_BT_CTLR_FAST_ENC)
-#pragma GCC optimize ("Ofast")
-#endif
 static uint16_t rng_pool_get(struct rng_pool *rngp, uint8_t *buf, uint16_t len)
 {
 	uint32_t last  = rngp->last;
@@ -175,7 +171,6 @@ static uint16_t rng_pool_get(struct rng_pool *rngp, uint8_t *buf, uint16_t len)
 
 	return len;
 }
-#pragma GCC pop_options
 
 static int rng_pool_put(struct rng_pool *rngp, uint8_t byte)
 {
diff --git a/drivers/entropy/entropy_smartbond.c b/drivers/entropy/entropy_smartbond.c
index 0058baafce5..28b6f08e100 100644
--- a/drivers/entropy/entropy_smartbond.c
+++ b/drivers/entropy/entropy_smartbond.c
@@ -100,10 +100,6 @@ static int random_word_get(uint8_t buf[4])
 	return retval;
 }
 
-#pragma GCC push_options
-#if defined(CONFIG_BT_CTLR_FAST_ENC)
-#pragma GCC optimize("Ofast")
-#endif
 static uint16_t rng_pool_get(struct rng_pool *rngp, uint8_t *buf, uint16_t len)
 {
 	uint32_t last = rngp->last;
@@ -159,7 +155,6 @@ static uint16_t rng_pool_get(struct rng_pool *rngp, uint8_t *buf, uint16_t len)
 
 	return len;
 }
-#pragma GCC pop_options
 
 static int rng_pool_put(struct rng_pool *rngp, uint8_t byte)
 {
diff --git a/drivers/entropy/entropy_stm32.c b/drivers/entropy/entropy_stm32.c
index cecff05e9e3..6627c648c47 100644
--- a/drivers/entropy/entropy_stm32.c
+++ b/drivers/entropy/entropy_stm32.c
@@ -378,13 +378,7 @@ static void pool_filling_work_handler(struct k_work *work)
 	}
 }
 
-#if defined(CONFIG_BT_CTLR_FAST_ENC)
-#define __fast __attribute__((optimize("Ofast")))
-#else
-#define __fast
-#endif
-
-__fast static uint16_t rng_pool_get(struct rng_pool *rngp, uint8_t *buf,
+static uint16_t rng_pool_get(struct rng_pool *rngp, uint8_t *buf,
 	uint16_t len)
 {
 	uint32_t last  = rngp->last;
@@ -449,7 +443,6 @@ __fast static uint16_t rng_pool_get(struct rng_pool *rngp, uint8_t *buf,
 
 	return len;
 }
-#undef __fast
 
 static int rng_pool_put(struct rng_pool *rngp, uint8_t byte)
 {
diff --git a/subsys/bluetooth/controller/Kconfig.ll_sw_split b/subsys/bluetooth/controller/Kconfig.ll_sw_split
index a7dade7a1db..e2975107f86 100644
--- a/subsys/bluetooth/controller/Kconfig.ll_sw_split
+++ b/subsys/bluetooth/controller/Kconfig.ll_sw_split
@@ -760,18 +760,6 @@ config BT_CTLR_PARAM_CHECK
 
 if BT_CONN
 
-config BT_CTLR_FAST_ENC
-	bool "Fast Encryption Setup"
-	depends on BT_CTLR_LE_ENC
-	default y if BT_HCI_RAW
-	help
-	  Enable connection encryption setup in 4 connection events.
-	  Peripheral will respond to Encryption Request with Encryption Response
-	  in the next connection event, and will transmit Start Encryption
-	  Request PDU in the same connection event, hence completing encryption
-	  setup in 4 connection events. Encrypted data would be transmitted as
-	  fast as in 4th connection event from Encryption Request.
-
 config BT_CTLR_LLCP_CONN
 	int "Number of connections with worst-case overlapping procedures"
 	default BT_MAX_CONN
diff --git a/tests/bluetooth/init/prj_ctlr_4_0.conf b/tests/bluetooth/init/prj_ctlr_4_0.conf
index ff3917be54b..4f9ec70d3bb 100644
--- a/tests/bluetooth/init/prj_ctlr_4_0.conf
+++ b/tests/bluetooth/init/prj_ctlr_4_0.conf
@@ -19,7 +19,6 @@ CONFIG_BT_CTLR_XTAL_ADVANCED=y
 CONFIG_BT_CTLR_SCHED_ADVANCED=y
 CONFIG_BT_CTLR_RADIO_ENABLE_FAST=n
 CONFIG_BT_CTLR_TIFS_HW=y
-CONFIG_BT_CTLR_FAST_ENC=n
 CONFIG_BT_CTLR_CONN_RSSI=n
 CONFIG_BT_CTLR_ADV_INDICATION=n
 CONFIG_BT_CTLR_SCAN_REQ_NOTIFY=n
diff --git a/tests/bluetooth/init/prj_ctlr_4_0_dbg.conf b/tests/bluetooth/init/prj_ctlr_4_0_dbg.conf
index 4c101cc6e16..5fc61cf98c6 100644
--- a/tests/bluetooth/init/prj_ctlr_4_0_dbg.conf
+++ b/tests/bluetooth/init/prj_ctlr_4_0_dbg.conf
@@ -21,7 +21,6 @@ CONFIG_BT_CTLR_XTAL_ADVANCED=y
 CONFIG_BT_CTLR_SCHED_ADVANCED=y
 CONFIG_BT_CTLR_RADIO_ENABLE_FAST=n
 CONFIG_BT_CTLR_TIFS_HW=y
-CONFIG_BT_CTLR_FAST_ENC=n
 CONFIG_BT_CTLR_CONN_RSSI=n
 CONFIG_BT_CTLR_ADV_INDICATION=n
 CONFIG_BT_CTLR_SCAN_REQ_NOTIFY=n
diff --git a/tests/bluetooth/init/prj_ctlr_5_x_dbg.conf b/tests/bluetooth/init/prj_ctlr_5_x_dbg.conf
index df0d006a13e..50f72889476 100644
--- a/tests/bluetooth/init/prj_ctlr_5_x_dbg.conf
+++ b/tests/bluetooth/init/prj_ctlr_5_x_dbg.conf
@@ -29,7 +29,6 @@ CONFIG_BT_CTLR_XTAL_ADVANCED=n
 CONFIG_BT_CTLR_SCHED_ADVANCED=y
 CONFIG_BT_CTLR_RADIO_ENABLE_FAST=y
 CONFIG_BT_CTLR_TIFS_HW=n
-CONFIG_BT_CTLR_FAST_ENC=y
 CONFIG_BT_CTLR_TX_RETRY_DISABLE=y
 CONFIG_BT_CTLR_CONN_RSSI=y
 CONFIG_BT_CTLR_ADV_INDICATION=y
diff --git a/tests/bluetooth/init/prj_ctlr_dbg.conf b/tests/bluetooth/init/prj_ctlr_dbg.conf
index 6aff0965ce9..2f8224cdfea 100644
--- a/tests/bluetooth/init/prj_ctlr_dbg.conf
+++ b/tests/bluetooth/init/prj_ctlr_dbg.conf
@@ -23,7 +23,6 @@ CONFIG_BT_CTLR_XTAL_ADVANCED=n
 CONFIG_BT_CTLR_SCHED_ADVANCED=n
 CONFIG_BT_CTLR_RADIO_ENABLE_FAST=y
 CONFIG_BT_CTLR_TIFS_HW=n
-CONFIG_BT_CTLR_FAST_ENC=y
 CONFIG_BT_CTLR_TX_RETRY_DISABLE=y
 CONFIG_BT_CTLR_CONN_RSSI=y
 CONFIG_BT_CTLR_ADV_INDICATION=y
diff --git a/tests/bluetooth/init/prj_ctlr_ticker.conf b/tests/bluetooth/init/prj_ctlr_ticker.conf
index d77f519406b..4e5b962231e 100644
--- a/tests/bluetooth/init/prj_ctlr_ticker.conf
+++ b/tests/bluetooth/init/prj_ctlr_ticker.conf
@@ -23,7 +23,6 @@ CONFIG_BT_CTLR_XTAL_ADVANCED=n
 CONFIG_BT_CTLR_SCHED_ADVANCED=n
 CONFIG_BT_CTLR_RADIO_ENABLE_FAST=y
 CONFIG_BT_CTLR_TIFS_HW=n
-CONFIG_BT_CTLR_FAST_ENC=y
 CONFIG_BT_CTLR_TX_RETRY_DISABLE=y
 CONFIG_BT_CTLR_CONN_RSSI=y
 CONFIG_BT_CTLR_ADV_INDICATION=y
diff --git a/tests/bluetooth/init/prj_ctlr_tiny.conf b/tests/bluetooth/init/prj_ctlr_tiny.conf
index 7679de9a661..ce75583da16 100644
--- a/tests/bluetooth/init/prj_ctlr_tiny.conf
+++ b/tests/bluetooth/init/prj_ctlr_tiny.conf
@@ -22,7 +22,6 @@ CONFIG_BT_CTLR_XTAL_ADVANCED=n
 CONFIG_BT_CTLR_SCHED_ADVANCED=n
 CONFIG_BT_CTLR_RADIO_ENABLE_FAST=n
 CONFIG_BT_CTLR_TIFS_HW=y
-CONFIG_BT_CTLR_FAST_ENC=n
 CONFIG_BT_CTLR_CONN_RSSI=n
 CONFIG_BT_CTLR_ADV_INDICATION=n
 CONFIG_BT_CTLR_SCAN_REQ_NOTIFY=n