diff --git a/doc/services/storage/secure_storage/index.rst b/doc/services/storage/secure_storage/index.rst
index 57f7dc03b27..1829b435ea9 100644
--- a/doc/services/storage/secure_storage/index.rst
+++ b/doc/services/storage/secure_storage/index.rst
@@ -43,9 +43,18 @@ The secure storage subsystem's implementation of the PSA Secure Storage API:
   Instead, the PS API directly calls into the Internal Trusted Storage (ITS) API
   (unless a `custom implementation <#whole-api>`_ of the PS API is provided).
 
-Below are some ways the implementation deviates from the specification
+Below are some ways the implementation purposefully deviates from the specification
 and an explanation why. This is not an exhaustive list.
 
+* The UID type is only 30 bits by default. (Against `2.5 UIDs <https://arm-software.github.io/psa-api/storage/1.0/overview/architecture.html#uids>`_.)
+
+  | This is an optimization done to make it more convenient to directly use the UIDs as
+    storage entry IDs (e.g., with :ref:`ZMS <zms_api>` when
+    :kconfig:option:`CONFIG_SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_ZMS` is enabled).
+  | Zephyr defines numerical ranges to be used by different users of the API which guarantees that
+    there are no collisions and that they all fit within 30 bits.
+    See the header files in :zephyr_file:`include/zephyr/psa` for more information.
+
 * The data stored in the ITS is by default encrypted and authenticated (Against ``1.`` in
   `3.2. Internal Trusted Storage requirements <https://arm-software.github.io/psa-api/storage/1.0/overview/requirements.html#internal-trusted-storage-requirements>`_.)
 
diff --git a/samples/psa/its/sample.yaml b/samples/psa/its/sample.yaml
index 8d67cddd157..d3e7b7e10c9 100644
--- a/samples/psa/its/sample.yaml
+++ b/samples/psa/its/sample.yaml
@@ -2,6 +2,8 @@ sample:
   name: PSA ITS API sample
   description: Demonstration of PSA Internal Trusted Storage (ITS) API usage.
 common:
+  integration_platforms:
+    - native_sim
   tags:
     - psa.secure_storage
   timeout: 10
diff --git a/samples/psa/persistent_key/sample.yaml b/samples/psa/persistent_key/sample.yaml
index 490f2ea8f15..7c5b9d80300 100644
--- a/samples/psa/persistent_key/sample.yaml
+++ b/samples/psa/persistent_key/sample.yaml
@@ -2,6 +2,8 @@ sample:
   name: PSA Crypto persistent key sample
   description: Demonstration of persistent key usage in the PSA Crypto API.
 common:
+  integration_platforms:
+    - native_sim
   tags:
     - psa.secure_storage
   timeout: 10
diff --git a/subsys/secure_storage/Kconfig b/subsys/secure_storage/Kconfig
index 3fe8eb0f76a..b0ac8c08a14 100644
--- a/subsys/secure_storage/Kconfig
+++ b/subsys/secure_storage/Kconfig
@@ -25,6 +25,17 @@ module = SECURE_STORAGE
 module-str = secure_storage
 source "subsys/logging/Kconfig.template.log_config"
 
+config SECURE_STORAGE_64_BIT_UID
+	bool "Make psa_storage_uid_t 64-bit"
+	help
+	  Zephyr, by default, uses a 30-bit psa_storage_uid_t, which allows using only 32 bits to
+	  identify entries.
+	  UID ranges are defined for the different users of the API which guarantees that all the
+	  UIDs fit within 30 bits. See for example the zephyr/psa/key_ids.h header file.
+	  Enable this for backward compatibility if you are updating an existing installation with
+	  stored entries that was using Zephyr prior to 4.3 or if for some reason you need the full
+	  64-bit UID range.
+
 choice SECURE_STORAGE_ITS_IMPLEMENTATION
 	prompt "Internal Trusted Storage (ITS) API implementation"
 
diff --git a/subsys/secure_storage/Kconfig.its_store b/subsys/secure_storage/Kconfig.its_store
index ccd15b968a7..c924def563f 100644
--- a/subsys/secure_storage/Kconfig.its_store
+++ b/subsys/secure_storage/Kconfig.its_store
@@ -17,7 +17,7 @@ config SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_ZMS
 	depends on ZMS
 	help
 	  This implementation of the ITS store module makes direct use of ZMS for storage.
-	  It needs a `secure_storage_its_partition` devicetree chosen property that points
+	  It needs a secure_storage_its_partition devicetree chosen property that points
 	  to a fixed storage partition that will be dedicated to the ITS. It has lower
 	  overhead compared to the settings-based implementation, both in terms of runtime
 	  execution and storage space, and also ROM footprint if the settings subsystem is disabled.
@@ -78,7 +78,8 @@ config SECURE_STORAGE_ITS_STORE_SETTINGS_PREFIX
 config SECURE_STORAGE_ITS_STORE_SETTINGS_NAME_MAX_LEN
 	int "Maximum setting name length"
 	range 2 64
-	default 22 if !SECURE_STORAGE_ITS_STORE_SETTINGS_NAME_CUSTOM
-	default 0
+	default 0 if SECURE_STORAGE_ITS_STORE_SETTINGS_NAME_CUSTOM
+	default 22 if SECURE_STORAGE_64_BIT_UID
+	default 14
 
 endif # SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_SETTINGS
diff --git a/subsys/secure_storage/include/internal/zephyr/secure_storage/its.h b/subsys/secure_storage/include/internal/zephyr/secure_storage/its.h
index 009bb5e061a..c19dd7be7b6 100644
--- a/subsys/secure_storage/include/internal/zephyr/secure_storage/its.h
+++ b/subsys/secure_storage/include/internal/zephyr/secure_storage/its.h
@@ -14,18 +14,21 @@
 #include "its/common.h"
 
 /** @brief See `psa_its_set()`, to which this function is analogous. */
-psa_status_t secure_storage_its_set(secure_storage_its_uid_t uid, size_t data_length,
-				    const void *p_data, psa_storage_create_flags_t create_flags);
+psa_status_t secure_storage_its_set(secure_storage_its_caller_id_t caller_id, psa_storage_uid_t uid,
+				    size_t data_length, const void *p_data,
+				    psa_storage_create_flags_t create_flags);
 
 /** @brief See `psa_its_get()`, to which this function is analogous. */
-psa_status_t secure_storage_its_get(secure_storage_its_uid_t uid, size_t data_offset,
-				    size_t data_size, void *p_data, size_t *p_data_length);
+psa_status_t secure_storage_its_get(secure_storage_its_caller_id_t caller_id, psa_storage_uid_t uid,
+				    size_t data_offset, size_t data_size,
+				    void *p_data, size_t *p_data_length);
 
 /** @brief See `psa_its_get_info()`, to which this function is analogous. */
-psa_status_t secure_storage_its_get_info(secure_storage_its_uid_t uid,
-					 struct psa_storage_info_t *p_info);
+psa_status_t secure_storage_its_get_info(secure_storage_its_caller_id_t caller_id,
+					 psa_storage_uid_t uid, struct psa_storage_info_t *p_info);
 
 /** @brief See `psa_its_remove()`, to which this function is analogous. */
-psa_status_t secure_storage_its_remove(secure_storage_its_uid_t uid);
+psa_status_t secure_storage_its_remove(secure_storage_its_caller_id_t caller_id,
+				       psa_storage_uid_t uid);
 
 #endif
diff --git a/subsys/secure_storage/include/internal/zephyr/secure_storage/its/common.h b/subsys/secure_storage/include/internal/zephyr/secure_storage/its/common.h
index cd953086950..6ffc1bc78f5 100644
--- a/subsys/secure_storage/include/internal/zephyr/secure_storage/its/common.h
+++ b/subsys/secure_storage/include/internal/zephyr/secure_storage/its/common.h
@@ -12,8 +12,7 @@
 #include <psa/storage_common.h>
 
 /** @brief The ID of the caller from which the ITS API call originates.
- * This is used to prevent ID collisions between different callers that are not aware
- * of each other and so might use the same numerical IDs, e.g. PSA Crypto and PSA ITS.
+ * This is used to namespace the different callers and possibly treat them differently.
  */
 typedef enum {
 	SECURE_STORAGE_ITS_CALLER_PSA_ITS,
@@ -22,12 +21,33 @@ typedef enum {
 	SECURE_STORAGE_ITS_CALLER_COUNT
 } secure_storage_its_caller_id_t;
 
+#ifdef CONFIG_SECURE_STORAGE_64_BIT_UID
+
 /** The UID (caller + entry IDs) of an ITS entry. */
 typedef struct {
 	psa_storage_uid_t uid;
 	secure_storage_its_caller_id_t caller_id;
 } __packed secure_storage_its_uid_t;
 
+#else
+
+#define SECURE_STORAGE_ITS_UID_BIT_SIZE 30
+#define SECURE_STORAGE_ITS_CALLER_ID_BIT_SIZE 2
+
+/** @brief The UID (caller + entry IDs) of an ITS entry.
+ * This is a packed, 32-bit version of `psa_storage_uid_t` which allows storing
+ * smaller IDs compared to the 64-bit ones that PSA Secure Storage specifies.
+ * Zephyr defines ranges of IDs to be used by different users of the API (subsystems, application)
+ * which guarantees 1. no collisions and 2. that the IDs used fit within `uid`.
+ * @see @ref zephyr/psa/key_ids.h and the other header files under `zephyr/psa`.
+ */
+typedef struct {
+	psa_storage_uid_t uid : SECURE_STORAGE_ITS_UID_BIT_SIZE;
+	secure_storage_its_caller_id_t caller_id : SECURE_STORAGE_ITS_CALLER_ID_BIT_SIZE;
+} secure_storage_its_uid_t;
+
+#endif /* CONFIG_SECURE_STORAGE_64_BIT_UID */
+
 #ifdef CONFIG_SECURE_STORAGE_ITS_TRANSFORM_MODULE
 
 /** The maximum size, in bytes, of an entry's data after it has been transformed for storage. */
diff --git a/subsys/secure_storage/include/psa/internal_trusted_storage.h b/subsys/secure_storage/include/psa/internal_trusted_storage.h
index a8c3b77c601..06a09e34988 100644
--- a/subsys/secure_storage/include/psa/internal_trusted_storage.h
+++ b/subsys/secure_storage/include/psa/internal_trusted_storage.h
@@ -16,7 +16,6 @@
 #else
 #define ITS_CALLER_ID SECURE_STORAGE_ITS_CALLER_PSA_ITS
 #endif
-#define ITS_UID (secure_storage_its_uid_t){.uid = uid, .caller_id = ITS_CALLER_ID}
 /** @endcond */
 
 #include <psa/storage_common.h>
@@ -50,7 +49,7 @@ static ALWAYS_INLINE
 psa_status_t psa_its_set(psa_storage_uid_t uid, size_t data_length,
 			 const void *p_data, psa_storage_create_flags_t create_flags)
 {
-	return secure_storage_its_set(ITS_UID, data_length, p_data, create_flags);
+	return secure_storage_its_set(ITS_CALLER_ID, uid, data_length, p_data, create_flags);
 }
 
 /**
@@ -76,7 +75,8 @@ static ALWAYS_INLINE
 psa_status_t psa_its_get(psa_storage_uid_t uid, size_t data_offset,
 			 size_t data_size, void *p_data, size_t *p_data_length)
 {
-	return secure_storage_its_get(ITS_UID, data_offset, data_size, p_data, p_data_length);
+	return secure_storage_its_get(ITS_CALLER_ID, uid, data_offset,
+				      data_size, p_data, p_data_length);
 }
 
 /**
@@ -96,7 +96,7 @@ static ALWAYS_INLINE
 /** @endcond  */
 psa_status_t psa_its_get_info(psa_storage_uid_t uid, struct psa_storage_info_t *p_info)
 {
-	return secure_storage_its_get_info(ITS_UID, p_info);
+	return secure_storage_its_get_info(ITS_CALLER_ID, uid, p_info);
 }
 
 /**
@@ -117,7 +117,7 @@ static ALWAYS_INLINE
 /** @endcond  */
 psa_status_t psa_its_remove(psa_storage_uid_t uid)
 {
-	return secure_storage_its_remove(ITS_UID);
+	return secure_storage_its_remove(ITS_CALLER_ID, uid);
 }
 
 #undef ITS_UID
diff --git a/subsys/secure_storage/include/psa/protected_storage.h b/subsys/secure_storage/include/psa/protected_storage.h
index 7c20d3097a2..40d731b0425 100644
--- a/subsys/secure_storage/include/psa/protected_storage.h
+++ b/subsys/secure_storage/include/psa/protected_storage.h
@@ -12,8 +12,7 @@
 /** @cond INTERNAL_HIDDEN */
 #ifdef CONFIG_SECURE_STORAGE_PS_IMPLEMENTATION_ITS
 #include "../internal/zephyr/secure_storage/its.h"
-#define ITS_UID (secure_storage_its_uid_t){.uid = uid, \
-					   .caller_id = SECURE_STORAGE_ITS_CALLER_PSA_PS}
+#define ITS_CALLER_ID SECURE_STORAGE_ITS_CALLER_PSA_PS
 #else
 #include "../internal/zephyr/secure_storage/ps.h"
 #endif
@@ -50,7 +49,7 @@ psa_status_t psa_ps_set(psa_storage_uid_t uid, size_t data_length,
 			const void *p_data, psa_storage_create_flags_t create_flags)
 {
 #ifdef CONFIG_SECURE_STORAGE_PS_IMPLEMENTATION_ITS
-	return secure_storage_its_set(ITS_UID, data_length, p_data, create_flags);
+	return secure_storage_its_set(ITS_CALLER_ID, uid, data_length, p_data, create_flags);
 #else
 	return secure_storage_ps_set(uid, data_length, p_data, create_flags);
 #endif
@@ -83,7 +82,8 @@ psa_status_t psa_ps_get(psa_storage_uid_t uid, size_t data_offset,
 			size_t data_size, void *p_data, size_t *p_data_length)
 {
 #ifdef CONFIG_SECURE_STORAGE_PS_IMPLEMENTATION_ITS
-	return secure_storage_its_get(ITS_UID, data_offset, data_size, p_data, p_data_length);
+	return secure_storage_its_get(ITS_CALLER_ID, uid, data_offset,
+				      data_size, p_data, p_data_length);
 #else
 	return secure_storage_ps_get(uid, data_offset, data_size, p_data, p_data_length);
 #endif
@@ -110,7 +110,7 @@ static ALWAYS_INLINE
 psa_status_t psa_ps_get_info(psa_storage_uid_t uid, struct psa_storage_info_t *p_info)
 {
 #ifdef CONFIG_SECURE_STORAGE_PS_IMPLEMENTATION_ITS
-	return secure_storage_its_get_info(ITS_UID, p_info);
+	return secure_storage_its_get_info(ITS_CALLER_ID, uid, p_info);
 #else
 	return secure_storage_ps_get_info(uid, p_info);
 #endif
@@ -138,7 +138,7 @@ static ALWAYS_INLINE
 psa_status_t psa_ps_remove(psa_storage_uid_t uid)
 {
 #ifdef CONFIG_SECURE_STORAGE_PS_IMPLEMENTATION_ITS
-	return secure_storage_its_remove(ITS_UID);
+	return secure_storage_its_remove(ITS_CALLER_ID, uid);
 #else
 	return secure_storage_ps_remove(uid);
 #endif
diff --git a/subsys/secure_storage/include/psa/storage_common.h b/subsys/secure_storage/include/psa/storage_common.h
index d5bed2a692e..2bd0f7cce73 100644
--- a/subsys/secure_storage/include/psa/storage_common.h
+++ b/subsys/secure_storage/include/psa/storage_common.h
@@ -20,7 +20,11 @@
 #include <stddef.h>
 
 /** UID type for identifying entries. */
+#ifdef CONFIG_SECURE_STORAGE_64_BIT_UID
 typedef uint64_t psa_storage_uid_t;
+#else
+typedef uint32_t psa_storage_uid_t;
+#endif
 
 /** Flags used when creating an entry. */
 typedef uint32_t psa_storage_create_flags_t;
diff --git a/subsys/secure_storage/src/its/implementation.c b/subsys/secure_storage/src/its/implementation.c
index 2ad937d45d2..6f33195a062 100644
--- a/subsys/secure_storage/src/its/implementation.c
+++ b/subsys/secure_storage/src/its/implementation.c
@@ -11,6 +11,33 @@
 
 LOG_MODULE_DECLARE(secure_storage, CONFIG_SECURE_STORAGE_LOG_LEVEL);
 
+#ifndef CONFIG_SECURE_STORAGE_64_BIT_UID
+BUILD_ASSERT(sizeof(secure_storage_its_uid_t) == 4); /* ITS UIDs are 32-bit */
+BUILD_ASSERT(1 << SECURE_STORAGE_ITS_CALLER_ID_BIT_SIZE >= SECURE_STORAGE_ITS_CALLER_COUNT);
+BUILD_ASSERT(SECURE_STORAGE_ITS_CALLER_ID_BIT_SIZE + SECURE_STORAGE_ITS_UID_BIT_SIZE == 32);
+#endif
+
+static psa_status_t make_its_uid(secure_storage_its_caller_id_t caller_id, psa_storage_uid_t uid,
+				 secure_storage_its_uid_t *its_uid)
+{
+	if (uid == 0) {
+		return PSA_ERROR_INVALID_ARGUMENT;
+	}
+
+#ifndef CONFIG_SECURE_STORAGE_64_BIT_UID
+	/* Check that the UID is not bigger than the maximum defined size. */
+	if (uid & GENMASK64(63, SECURE_STORAGE_ITS_UID_BIT_SIZE)) {
+		LOG_DBG("UID %u/%#llx cannot be used as it has bits set past "
+			"the first " STRINGIFY(SECURE_STORAGE_ITS_UID_BIT_SIZE) " ones.",
+			caller_id, (unsigned long long)uid);
+		return PSA_ERROR_INVALID_ARGUMENT;
+	}
+#endif /* !CONFIG_SECURE_STORAGE_64_BIT_UID */
+
+	*its_uid = (secure_storage_its_uid_t){.caller_id = caller_id, .uid = uid};
+	return PSA_SUCCESS;
+}
+
 static void log_failed_operation(const char *operation, const char *preposition, psa_status_t ret)
 {
 	LOG_ERR("Failed to %s data %s storage. (%d)", operation, preposition, ret);
@@ -88,8 +115,15 @@ static bool keep_stored_entry(secure_storage_its_uid_t uid, size_t data_length,
 	if (existing_data_len == data_length &&
 	    existing_create_flags == create_flags &&
 	    !memcmp(existing_data, p_data, data_length)) {
-		LOG_DBG("Not writing entry %u/%llu to storage because its stored data"
-			" (of length %zu) is identical.", uid.caller_id, uid.uid, data_length);
+#ifdef CONFIG_SECURE_STORAGE_64_BIT_UID
+		LOG_DBG("Not writing entry %u/%#llx to storage because its stored data"
+			" (of length %zu) is identical.", uid.caller_id,
+			(unsigned long long)uid.uid, data_length);
+#else
+		LOG_DBG("Not writing entry %u/%#lx to storage because its stored data"
+			" (of length %zu) is identical.", uid.caller_id,
+			(unsigned long)uid.uid, data_length);
+#endif
 		*ret = PSA_SUCCESS;
 		return true;
 	}
@@ -117,12 +151,17 @@ static psa_status_t store_entry(secure_storage_its_uid_t uid, size_t data_length
 	return ret;
 }
 
-psa_status_t secure_storage_its_set(secure_storage_its_uid_t uid, size_t data_length,
-				    const void *p_data, psa_storage_create_flags_t create_flags)
+psa_status_t secure_storage_its_set(secure_storage_its_caller_id_t caller_id, psa_storage_uid_t uid,
+				    size_t data_length, const void *p_data,
+				    psa_storage_create_flags_t create_flags)
 {
 	psa_status_t ret;
+	secure_storage_its_uid_t its_uid;
 
-	if (uid.uid == 0 || (p_data == NULL && data_length != 0)) {
+	if (make_its_uid(caller_id, uid, &its_uid) != PSA_SUCCESS) {
+		return PSA_ERROR_INVALID_ARGUMENT;
+	}
+	if (p_data == NULL && data_length != 0) {
 		return PSA_ERROR_INVALID_ARGUMENT;
 	}
 	if (create_flags & ~SECURE_STORAGE_ALL_CREATE_FLAGS) {
@@ -134,43 +173,49 @@ psa_status_t secure_storage_its_set(secure_storage_its_uid_t uid, size_t data_le
 		return PSA_ERROR_INSUFFICIENT_STORAGE;
 	}
 
-	if (keep_stored_entry(uid, data_length, p_data, create_flags, &ret)) {
+	if (keep_stored_entry(its_uid, data_length, p_data, create_flags, &ret)) {
 		return ret;
 	}
 
-	ret = store_entry(uid, data_length, p_data, create_flags);
+	ret = store_entry(its_uid, data_length, p_data, create_flags);
 	return ret;
 }
-
-psa_status_t secure_storage_its_get(secure_storage_its_uid_t uid, size_t data_offset,
-				    size_t data_size, void *p_data, size_t *p_data_length)
+psa_status_t secure_storage_its_get(secure_storage_its_caller_id_t caller_id, psa_storage_uid_t uid,
+				    size_t data_offset, size_t data_size,
+				    void *p_data, size_t *p_data_length)
 {
-	if (uid.uid == 0 || (p_data == NULL && data_size != 0) || p_data_length == NULL) {
+	psa_status_t ret;
+	secure_storage_its_uid_t its_uid;
+	uint8_t stored_data[SECURE_STORAGE_ITS_TRANSFORM_MAX_STORED_DATA_SIZE];
+	size_t stored_data_len;
+	psa_storage_create_flags_t create_flags;
+
+	if (make_its_uid(caller_id, uid, &its_uid) != PSA_SUCCESS) {
+		return PSA_ERROR_INVALID_ARGUMENT;
+	}
+	if ((p_data == NULL && data_size != 0) || p_data_length == NULL) {
 		return PSA_ERROR_INVALID_ARGUMENT;
 	}
 	if (data_size == 0) {
 		*p_data_length = 0;
 		return PSA_SUCCESS;
 	}
-	psa_status_t ret;
-	uint8_t stored_data[SECURE_STORAGE_ITS_TRANSFORM_MAX_STORED_DATA_SIZE];
-	size_t stored_data_len;
-	psa_storage_create_flags_t create_flags;
 
-	ret = get_stored_data(uid, stored_data, &stored_data_len);
+
+	ret = get_stored_data(its_uid, stored_data, &stored_data_len);
 	if (ret != PSA_SUCCESS) {
 		return ret;
 	}
 	if (data_offset == 0
 	 && data_size >= SECURE_STORAGE_ITS_TRANSFORM_DATA_SIZE(stored_data_len)) {
 		/* All the data fits directly in the provided buffer. */
-		return transform_stored_data(uid, stored_data_len, stored_data, data_size, p_data,
-					     p_data_length, &create_flags);
+		return transform_stored_data(its_uid, stored_data_len, stored_data, data_size,
+					     p_data, p_data_length, &create_flags);
 	}
 	uint8_t data[CONFIG_SECURE_STORAGE_ITS_MAX_DATA_SIZE];
 	size_t data_len;
 
-	ret = transform_stored_data(uid, stored_data_len, stored_data, sizeof(data), data,
+	ret = transform_stored_data(its_uid, stored_data_len, stored_data, sizeof(data), data,
 				    &data_len, &create_flags);
 	if (ret == PSA_SUCCESS) {
 		if (data_offset > data_len) {
@@ -184,41 +229,47 @@ psa_status_t secure_storage_its_get(secure_storage_its_uid_t uid, size_t data_of
 	return ret;
 }
 
-psa_status_t secure_storage_its_get_info(secure_storage_its_uid_t uid,
-					 struct psa_storage_info_t *p_info)
+psa_status_t secure_storage_its_get_info(secure_storage_its_caller_id_t caller_id,
+					 psa_storage_uid_t uid, struct psa_storage_info_t *p_info)
 {
 	psa_status_t ret;
+	secure_storage_its_uid_t its_uid;
 	uint8_t data[CONFIG_SECURE_STORAGE_ITS_MAX_DATA_SIZE];
 
-	if (uid.uid == 0 || p_info == NULL) {
+	if (make_its_uid(caller_id, uid, &its_uid) != PSA_SUCCESS) {
+		return PSA_ERROR_INVALID_ARGUMENT;
+	}
+	if (p_info == NULL) {
 		return PSA_ERROR_INVALID_ARGUMENT;
 	}
 
-	ret = get_entry(uid, sizeof(data), data, &p_info->size, &p_info->flags);
+	ret = get_entry(its_uid, sizeof(data), data, &p_info->size, &p_info->flags);
 	if (ret == PSA_SUCCESS) {
 		p_info->capacity = p_info->size;
 	}
 	return ret;
 }
 
-psa_status_t secure_storage_its_remove(secure_storage_its_uid_t uid)
+psa_status_t secure_storage_its_remove(secure_storage_its_caller_id_t caller_id,
+				       psa_storage_uid_t uid)
 {
 	psa_status_t ret;
+	secure_storage_its_uid_t its_uid;
 	psa_storage_create_flags_t create_flags;
 	uint8_t data[CONFIG_SECURE_STORAGE_ITS_MAX_DATA_SIZE];
 	size_t data_len;
 
-	if (uid.uid == 0) {
+	if (make_its_uid(caller_id, uid, &its_uid) != PSA_SUCCESS) {
 		return PSA_ERROR_INVALID_ARGUMENT;
 	}
 
-	ret = get_entry(uid, sizeof(data), data, &data_len, &create_flags);
+	ret = get_entry(its_uid, sizeof(data), data, &data_len, &create_flags);
 	if (ret == PSA_SUCCESS && (create_flags & PSA_STORAGE_FLAG_WRITE_ONCE)) {
 		return PSA_ERROR_NOT_PERMITTED;
 	}
 	/* Allow overwriting corrupted entries as well to not be stuck with them forever. */
 	if (ret == PSA_SUCCESS || ret == PSA_ERROR_STORAGE_FAILURE) {
-		ret = secure_storage_its_store_remove(uid);
+		ret = secure_storage_its_store_remove(its_uid);
 		if (ret != PSA_SUCCESS) {
 			log_failed_operation("remove", "from", ret);
 			return PSA_ERROR_STORAGE_FAILURE;
diff --git a/subsys/secure_storage/src/its/store/settings.c b/subsys/secure_storage/src/its/store/settings.c
index 962fa516770..37973ffb024 100644
--- a/subsys/secure_storage/src/its/store/settings.c
+++ b/subsys/secure_storage/src/its/store/settings.c
@@ -38,9 +38,15 @@ void secure_storage_its_store_settings_get_name(
 {
 	int ret;
 
+#ifdef CONFIG_SECURE_STORAGE_64_BIT_UID
 	ret = snprintf(name, SECURE_STORAGE_ITS_STORE_SETTINGS_NAME_BUF_SIZE,
 		       CONFIG_SECURE_STORAGE_ITS_STORE_SETTINGS_PREFIX "%x/%llx",
 		       uid.caller_id, (unsigned long long)uid.uid);
+#else
+	ret = snprintf(name, SECURE_STORAGE_ITS_STORE_SETTINGS_NAME_BUF_SIZE,
+		       CONFIG_SECURE_STORAGE_ITS_STORE_SETTINGS_PREFIX "%x/%lx",
+		       uid.caller_id, (unsigned long)uid.uid);
+#endif
 	__ASSERT_NO_MSG(ret > 0 && ret < SECURE_STORAGE_ITS_STORE_SETTINGS_NAME_BUF_SIZE);
 }
 
diff --git a/subsys/secure_storage/src/its/store/zms.c b/subsys/secure_storage/src/its/store/zms.c
index ede296952ab..4778e0365e9 100644
--- a/subsys/secure_storage/src/its/store/zms.c
+++ b/subsys/secure_storage/src/its/store/zms.c
@@ -33,26 +33,26 @@ static int init_zms(void)
 }
 SYS_INIT(init_zms, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);
 
+#ifdef CONFIG_SECURE_STORAGE_64_BIT_UID
+
 /* Bit position of the ITS caller ID in the ZMS entry ID. */
 #define ITS_CALLER_ID_POS 30
 /* Make sure that every ITS caller ID fits in ZMS entry IDs at the defined position. */
 BUILD_ASSERT(1 << (32 - ITS_CALLER_ID_POS) >= SECURE_STORAGE_ITS_CALLER_COUNT);
 
-static bool has_forbidden_bits_set(secure_storage_its_uid_t uid)
+static uint32_t zms_id_from(secure_storage_its_uid_t uid)
 {
-	if (uid.uid & GENMASK64(63, ITS_CALLER_ID_POS)) {
-		LOG_DBG("UID %u/0x%llx cannot be used as it has bits set past "
-			"the first " STRINGIFY(ITS_CALLER_ID_POS) " ones.",
-			uid.caller_id, (unsigned long long)uid.uid);
-		return true;
-	}
-	return false;
+	__ASSERT_NO_MSG(!(uid.uid & GENMASK64(63, ITS_CALLER_ID_POS)));
+	return (uint32_t)uid.uid | (uid.caller_id << ITS_CALLER_ID_POS);
 }
+#else
 
 static uint32_t zms_id_from(secure_storage_its_uid_t uid)
 {
-	return (uint32_t)uid.uid | (uid.caller_id << ITS_CALLER_ID_POS);
+	BUILD_ASSERT(sizeof(uid) == sizeof(uint32_t));
+	return *(uint32_t *)&uid;
 }
+#endif /* CONFIG_SECURE_STORAGE_64_BIT_UID */
 
 psa_status_t secure_storage_its_store_set(secure_storage_its_uid_t uid,
 					  size_t data_length, const void *data)
@@ -61,10 +61,6 @@ psa_status_t secure_storage_its_store_set(secure_storage_its_uid_t uid,
 	ssize_t zms_ret;
 	const uint32_t zms_id = zms_id_from(uid);
 
-	if (has_forbidden_bits_set(uid)) {
-		return PSA_ERROR_INVALID_ARGUMENT;
-	}
-
 	zms_ret = zms_write(&s_zms, zms_id, data, data_length);
 	if (zms_ret == data_length) {
 		psa_ret = PSA_SUCCESS;
@@ -73,7 +69,7 @@ psa_status_t secure_storage_its_store_set(secure_storage_its_uid_t uid,
 	} else {
 		psa_ret = PSA_ERROR_STORAGE_FAILURE;
 	}
-	LOG_DBG("%s 0x%x with %zu bytes. (%zd)", (psa_ret == PSA_SUCCESS) ?
+	LOG_DBG("%s %#x with %zu bytes. (%zd)", (psa_ret == PSA_SUCCESS) ?
 		"Wrote" : "Failed to write", zms_id, data_length, zms_ret);
 	return psa_ret;
 }
@@ -85,10 +81,6 @@ psa_status_t secure_storage_its_store_get(secure_storage_its_uid_t uid, size_t d
 	ssize_t zms_ret;
 	const uint32_t zms_id = zms_id_from(uid);
 
-	if (has_forbidden_bits_set(uid)) {
-		return PSA_ERROR_INVALID_ARGUMENT;
-	}
-
 	zms_ret = zms_read(&s_zms, zms_id, data, data_size);
 	if (zms_ret > 0) {
 		*data_length = zms_ret;
@@ -98,7 +90,7 @@ psa_status_t secure_storage_its_store_get(secure_storage_its_uid_t uid, size_t d
 	} else {
 		psa_ret = PSA_ERROR_STORAGE_FAILURE;
 	}
-	LOG_DBG("%s 0x%x for up to %zu bytes. (%zd)", (psa_ret != PSA_ERROR_STORAGE_FAILURE) ?
+	LOG_DBG("%s %#x for up to %zu bytes. (%zd)", (psa_ret != PSA_ERROR_STORAGE_FAILURE) ?
 		"Read" : "Failed to read", zms_id, data_size, zms_ret);
 	return psa_ret;
 }
@@ -108,12 +100,8 @@ psa_status_t secure_storage_its_store_remove(secure_storage_its_uid_t uid)
 	int ret;
 	const uint32_t zms_id = zms_id_from(uid);
 
-	if (has_forbidden_bits_set(uid)) {
-		return PSA_ERROR_INVALID_ARGUMENT;
-	}
-
 	ret = zms_delete(&s_zms, zms_id);
-	LOG_DBG("%s 0x%x. (%d)", ret ? "Failed to delete" : "Deleted", zms_id, ret);
+	LOG_DBG("%s %#x. (%d)", ret ? "Failed to delete" : "Deleted", zms_id, ret);
 
 	return ret ? PSA_ERROR_STORAGE_FAILURE : PSA_SUCCESS;
 }
diff --git a/tests/subsys/secure_storage/psa/crypto/testcase.yaml b/tests/subsys/secure_storage/psa/crypto/testcase.yaml
index 8755a5a1935..1482d23cb6c 100644
--- a/tests/subsys/secure_storage/psa/crypto/testcase.yaml
+++ b/tests/subsys/secure_storage/psa/crypto/testcase.yaml
@@ -8,7 +8,6 @@ tests:
     integration_platforms:
       - native_sim
       - nrf54l15dk/nrf54l15/cpuapp
-      - ophelia4ev/nrf54l15/cpuapp
   secure_storage.psa.crypto.tfm:
     filter: CONFIG_BUILD_WITH_TFM
     extra_args: EXTRA_CONF_FILE=overlay-tfm.conf
diff --git a/tests/subsys/secure_storage/psa/its/overlay-store_zms.conf b/tests/subsys/secure_storage/psa/its/overlay-store_zms.conf
index 7efe611bc0a..6c36dd40297 100644
--- a/tests/subsys/secure_storage/psa/its/overlay-store_zms.conf
+++ b/tests/subsys/secure_storage/psa/its/overlay-store_zms.conf
@@ -1,3 +1,4 @@
 CONFIG_SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_ZMS=y
 CONFIG_ZMS=y
 CONFIG_FLASH=y
+CONFIG_FLASH_MAP=y
diff --git a/tests/subsys/secure_storage/psa/its/testcase.yaml b/tests/subsys/secure_storage/psa/its/testcase.yaml
index 74bcec13586..0125b9d1e21 100644
--- a/tests/subsys/secure_storage/psa/its/testcase.yaml
+++ b/tests/subsys/secure_storage/psa/its/testcase.yaml
@@ -2,7 +2,6 @@ common:
   integration_platforms:
     - native_sim
     - nrf54l15dk/nrf54l15/cpuapp
-    - ophelia4ev/nrf54l15/cpuapp
   platform_exclude:
     - qemu_cortex_m0 # settings subsystem initialization fails
   timeout: 600
@@ -10,10 +9,9 @@ common:
     - psa.secure_storage
 tests:
   secure_storage.psa.its.secure_storage.store.zms:
-    filter: CONFIG_SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_ZMS
     # DT-based filtering is not possible for this test scenario.
     # Platforms with a storage_partition must be manually added here.
-    platform_allow:
+    platform_allow: &zms_platform_allow
       - native_sim
       - mps2/an385
       - qemu_x86/atom
@@ -25,15 +23,30 @@ tests:
       - nrf9160dk/nrf9160
       - nrf9161dk/nrf9161
       - ophelia4ev/nrf54l15/cpuapp
-    extra_args:
+    extra_args: &zms_extra_args
       - EXTRA_DTC_OVERLAY_FILE=zms.overlay
-      - EXTRA_CONF_FILE=overlay-secure_storage.conf;overlay-store_zms.conf;overlay-transform_default.conf
+      - EXTRA_CONF_FILE=\
+        overlay-secure_storage.conf;overlay-store_zms.conf;overlay-transform_default.conf
       - SB_CONFIG_PARTITION_MANAGER=n
 
+  secure_storage.psa.its.secure_storage.store.zms.64-bit_uids:
+    platform_allow: *zms_platform_allow
+    extra_args: *zms_extra_args
+    extra_configs:
+      - CONFIG_SECURE_STORAGE_64_BIT_UID=y
+
   secure_storage.psa.its.secure_storage.store.settings:
-    filter: CONFIG_SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_SETTINGS
-    extra_args: "EXTRA_CONF_FILE=\
-      overlay-secure_storage.conf;overlay-transform_default.conf;overlay-store_settings.conf"
+    filter: &settings_filter
+      CONFIG_SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_SETTINGS
+    extra_args: &settings_extra_args
+      "EXTRA_CONF_FILE=\
+       overlay-secure_storage.conf;overlay-transform_default.conf;overlay-store_settings.conf"
+
+  secure_storage.psa.its.secure_storage.store.settings.64-bit_uids:
+    filter: *settings_filter
+    extra_args: *settings_extra_args
+    extra_configs:
+      - CONFIG_SECURE_STORAGE_64_BIT_UID=y
 
   secure_storage.psa.its.secure_storage.custom.transform:
     filter: CONFIG_SECURE_STORAGE and not CONFIG_SECURE_STORAGE_ITS_STORE_IMPLEMENTATION_NONE