diff --git a/interface/src/tfm_ps_ipc_api.c b/interface/src/tfm_ps_ipc_api.c
index 106917e..c74c425 100644
--- a/interface/src/tfm_ps_ipc_api.c
+++ b/interface/src/tfm_ps_ipc_api.c
@@ -9,6 +9,7 @@
 #include "psa/protected_storage.h"
 #include "psa_manifest/sid.h"
 #include "tfm_ns_interface.h"
+#include "tfm_ps_defs.h"
 
 psa_status_t psa_ps_set(psa_storage_uid_t uid,
                         size_t data_length,
@@ -16,7 +17,6 @@
                         psa_storage_create_flags_t create_flags)
 {
     psa_status_t status;
-    psa_handle_t handle;
 
     psa_invec in_vec[] = {
         { .base = &uid,   .len = sizeof(uid) },
@@ -24,15 +24,8 @@
         { .base = &create_flags, .len = sizeof(create_flags) }
     };
 
-    handle = psa_connect(TFM_PS_SET_SID, TFM_PS_SET_VERSION);
-    if (!PSA_HANDLE_IS_VALID(handle)) {
-        return PSA_ERROR_GENERIC_ERROR;
-    }
-
-    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec),
-                      NULL, 0);
-
-    psa_close(handle);
+    status = psa_call(TFM_PROTECTED_STORAGE_SERVICE_HANDLE, TFM_PS_SET, in_vec,
+                      IOVEC_LEN(in_vec), NULL, 0);
 
     return status;
 }
@@ -44,7 +37,6 @@
                         size_t *p_data_length)
 {
     psa_status_t status;
-    psa_handle_t handle;
 
     psa_invec in_vec[] = {
         { .base = &uid, .len = sizeof(uid) },
@@ -59,15 +51,8 @@
         return PSA_ERROR_INVALID_ARGUMENT;
     }
 
-    handle = psa_connect(TFM_PS_GET_SID, TFM_PS_GET_VERSION);
-    if (!PSA_HANDLE_IS_VALID(handle)) {
-        return PSA_ERROR_GENERIC_ERROR;
-    }
-
-    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
-                      IOVEC_LEN(out_vec));
-
-    psa_close(handle);
+    status = psa_call(TFM_PROTECTED_STORAGE_SERVICE_HANDLE, TFM_PS_GET, in_vec,
+                      IOVEC_LEN(in_vec), out_vec, IOVEC_LEN(out_vec));
 
     *p_data_length = out_vec[0].len;
 
@@ -78,7 +63,6 @@
                              struct psa_storage_info_t *p_info)
 {
     psa_status_t status;
-    psa_handle_t handle;
 
     psa_invec in_vec[] = {
         { .base = &uid, .len = sizeof(uid) }
@@ -88,15 +72,8 @@
         { .base = p_info, .len = sizeof(*p_info) }
     };
 
-    handle = psa_connect(TFM_PS_GET_INFO_SID, TFM_PS_GET_INFO_VERSION);
-    if (!PSA_HANDLE_IS_VALID(handle)) {
-        return PSA_ERROR_GENERIC_ERROR;
-    }
-
-    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
-                      IOVEC_LEN(out_vec));
-
-    psa_close(handle);
+    status = psa_call(TFM_PROTECTED_STORAGE_SERVICE_HANDLE, TFM_PS_GET_INFO,
+                      in_vec, IOVEC_LEN(in_vec), out_vec, IOVEC_LEN(out_vec));
 
     return status;
 }
@@ -104,22 +81,13 @@
 psa_status_t psa_ps_remove(psa_storage_uid_t uid)
 {
     psa_status_t status;
-    psa_handle_t handle;
 
     psa_invec in_vec[] = {
         { .base = &uid, .len = sizeof(uid) }
     };
 
-
-    handle = psa_connect(TFM_PS_REMOVE_SID, TFM_PS_REMOVE_VERSION);
-    if (!PSA_HANDLE_IS_VALID(handle)) {
-        return PSA_ERROR_GENERIC_ERROR;
-    }
-
-    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec),
-                      NULL, 0);
-
-    psa_close(handle);
+    status = psa_call(TFM_PROTECTED_STORAGE_SERVICE_HANDLE, TFM_PS_REMOVE,
+                      in_vec, IOVEC_LEN(in_vec), NULL, 0);
 
     return status;
 }
@@ -151,7 +119,6 @@
      * uninitialised value in case the secure function fails.
      */
     uint32_t support_flags = 0;
-    psa_handle_t handle;
 
     psa_outvec out_vec[] = {
         { .base = &support_flags, .len = sizeof(support_flags) }
@@ -160,14 +127,8 @@
     /* The PSA API does not return an error, so any error from TF-M is
      * ignored.
      */
-    handle = psa_connect(TFM_PS_GET_SUPPORT_SID, TFM_PS_GET_SUPPORT_VERSION);
-    if (!PSA_HANDLE_IS_VALID(handle)) {
-        return support_flags;
-    }
-
-    (void)psa_call(handle, PSA_IPC_CALL, NULL, 0, out_vec, IOVEC_LEN(out_vec));
-
-    psa_close(handle);
+    (void)psa_call(TFM_PROTECTED_STORAGE_SERVICE_HANDLE, TFM_PS_GET_SUPPORT,
+                   NULL, 0, out_vec, IOVEC_LEN(out_vec));
 
     return support_flags;
 }