diff --git a/interface/src/tfm_sst_func_api.c b/interface/src/tfm_sst_func_api.c
index 6d94d67..77a466e 100644
--- a/interface/src/tfm_sst_func_api.c
+++ b/interface/src/tfm_sst_func_api.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2017-2020, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -12,73 +12,72 @@
 
 #define IOVEC_LEN(x) (uint32_t)(sizeof(x)/sizeof(x[0]))
 
-psa_ps_status_t psa_ps_set(psa_ps_uid_t uid,
-                           uint32_t data_length,
-                           const void *p_data,
-                           psa_ps_create_flags_t create_flags)
+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)
 {
     psa_status_t status;
-    psa_ps_status_t err;
     psa_invec in_vec[] = {
         { .base = &uid,   .len = sizeof(uid) },
         { .base = p_data, .len = data_length },
         { .base = &create_flags, .len = sizeof(create_flags) }
     };
 
-    psa_outvec out_vec[] = {
-        { .base = &err , .len = sizeof(err) }
-    };
-
     status = tfm_ns_interface_dispatch(
                                   (veneer_fn)tfm_tfm_sst_set_req_veneer,
                                   (uint32_t)in_vec,  IOVEC_LEN(in_vec),
-                                  (uint32_t)out_vec, IOVEC_LEN(out_vec));
-    if (status != PSA_SUCCESS) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
-    }
+                                  (uint32_t)NULL, 0);
 
-    return err;
+    /* A parameter with a buffer pointer pointer that has data length longer
+     * than maximum permitted is treated as a secure violation.
+     * TF-M framework rejects the request with TFM_ERROR_INVALID_PARAMETER.
+     */
+    if (status == (psa_status_t)TFM_ERROR_INVALID_PARAMETER) {
+        return PSA_ERROR_INVALID_ARGUMENT;
+    }
+    return status;
 }
 
-psa_ps_status_t psa_ps_get(psa_ps_uid_t uid,
-                           uint32_t data_offset,
-                           uint32_t data_length,
-                           void *p_data)
+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)
 {
     psa_status_t status;
-    psa_ps_status_t err;
     psa_invec in_vec[] = {
         { .base = &uid, .len = sizeof(uid) },
         { .base = &data_offset, .len = sizeof(data_offset) }
     };
 
     psa_outvec out_vec[] = {
-        { .base = &err,   .len = sizeof(err) },
-        { .base = p_data, .len = data_length }
+        { .base = p_data, .len = data_size }
     };
 
+    if (p_data_length == NULL) {
+        return PSA_ERROR_INVALID_ARGUMENT;
+    }
+
     status = tfm_ns_interface_dispatch(
                                   (veneer_fn)tfm_tfm_sst_get_req_veneer,
                                   (uint32_t)in_vec,  IOVEC_LEN(in_vec),
                                   (uint32_t)out_vec, IOVEC_LEN(out_vec));
 
-    if (status != PSA_SUCCESS) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
-    }
+    *p_data_length = out_vec[0].len;
 
-    return err;
+    return status;
 }
 
-psa_ps_status_t psa_ps_get_info(psa_ps_uid_t uid, struct psa_ps_info_t *p_info)
+psa_status_t psa_ps_get_info(psa_storage_uid_t uid,
+                             struct psa_storage_info_t *p_info)
 {
     psa_status_t status;
-    psa_ps_status_t err;
     psa_invec in_vec[] = {
         { .base = &uid, .len = sizeof(uid) }
     };
 
     psa_outvec out_vec[] = {
-        { .base = &err,   .len = sizeof(err) },
         { .base = p_info, .len = sizeof(*p_info) }
     };
 
@@ -87,56 +86,44 @@
                                   (uint32_t)in_vec,  IOVEC_LEN(in_vec),
                                   (uint32_t)out_vec, IOVEC_LEN(out_vec));
 
-    if (status != PSA_SUCCESS) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
-    }
-
-    return err;
+    return status;
 }
 
-psa_ps_status_t psa_ps_remove(psa_ps_uid_t uid)
+psa_status_t psa_ps_remove(psa_storage_uid_t uid)
 {
     psa_status_t status;
-    psa_ps_status_t err;
     psa_invec in_vec[] = {
         { .base = &uid, .len = sizeof(uid) }
     };
 
-    psa_outvec out_vec[] = {
-        { .base = &err, .len = sizeof(err) }
-    };
-
     status = tfm_ns_interface_dispatch(
                                   (veneer_fn)tfm_tfm_sst_remove_req_veneer,
                                   (uint32_t)in_vec,  IOVEC_LEN(in_vec),
-                                  (uint32_t)out_vec, IOVEC_LEN(out_vec));
+                                  (uint32_t)NULL, 0);
 
-    if (status != PSA_SUCCESS) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
-    }
-
-    return err;
+    return status;
 }
 
-psa_ps_status_t psa_ps_create(psa_ps_uid_t uid, uint32_t size,
-                              psa_ps_create_flags_t create_flags)
+psa_status_t psa_ps_create(psa_storage_uid_t uid,
+                           size_t capacity,
+                           psa_storage_create_flags_t create_flags)
 {
     (void)uid;
-    (void)size;
+    (void)capacity;
     (void)create_flags;
 
-    return PSA_PS_ERROR_NOT_SUPPORTED;
+    return PSA_ERROR_NOT_SUPPORTED;
 }
 
-psa_ps_status_t psa_ps_set_extended(psa_ps_uid_t uid, uint32_t data_offset,
-                                    uint32_t data_length, const void *p_data)
+psa_status_t psa_ps_set_extended(psa_storage_uid_t uid, size_t data_offset,
+                                 size_t data_length, const void *p_data)
 {
     (void)uid;
     (void)data_offset;
     (void)data_length;
     (void)p_data;
 
-    return PSA_PS_ERROR_NOT_SUPPORTED;
+    return PSA_ERROR_NOT_SUPPORTED;
 }
 
 uint32_t psa_ps_get_support(void)
diff --git a/interface/src/tfm_sst_ipc_api.c b/interface/src/tfm_sst_ipc_api.c
index 9ef95ff..8d0dc43 100644
--- a/interface/src/tfm_sst_ipc_api.c
+++ b/interface/src/tfm_sst_ipc_api.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2017-2020, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -13,13 +13,12 @@
 
 #define IOVEC_LEN(x) (uint32_t)(sizeof(x)/sizeof(x[0]))
 
-psa_ps_status_t psa_ps_set(psa_ps_uid_t uid,
-                           uint32_t data_length,
-                           const void *p_data,
-                           psa_ps_create_flags_t create_flags)
+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)
 {
     psa_status_t status;
-    psa_ps_status_t err;
     psa_handle_t handle;
 
     psa_invec in_vec[] = {
@@ -28,34 +27,34 @@
         { .base = &create_flags, .len = sizeof(create_flags) }
     };
 
-    psa_outvec out_vec[] = {
-        { .base = &err , .len = sizeof(err) }
-    };
-
     handle = psa_connect(TFM_SST_SET_SID, TFM_SST_SET_VERSION);
     if (!PSA_HANDLE_IS_VALID(handle)) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
+        return PSA_ERROR_GENERIC_ERROR;
     }
 
-    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
-                      IOVEC_LEN(out_vec));
+    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec),
+                      NULL, 0);
 
     psa_close(handle);
 
-    if (status != PSA_SUCCESS) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
+    /* A parameter with a buffer pointer pointer that has data length longer
+     * than maximum permitted is treated as a secure violation.
+     * TF-M framework rejects the request with TFM_ERROR_INVALID_PARAMETER.
+     */
+    if (status == (psa_status_t)TFM_ERROR_INVALID_PARAMETER) {
+        return PSA_ERROR_INVALID_ARGUMENT;
     }
 
-    return err;
+    return status;
 }
 
-psa_ps_status_t psa_ps_get(psa_ps_uid_t uid,
-                           uint32_t data_offset,
-                           uint32_t data_length,
-                           void *p_data)
+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)
 {
     psa_status_t status;
-    psa_ps_status_t err;
     psa_handle_t handle;
 
     psa_invec in_vec[] = {
@@ -64,13 +63,16 @@
     };
 
     psa_outvec out_vec[] = {
-        { .base = &err,   .len = sizeof(err) },
-        { .base = p_data, .len = data_length }
+        { .base = p_data, .len = data_size }
     };
 
+    if (p_data_length == NULL) {
+        return PSA_ERROR_INVALID_ARGUMENT;
+    }
+
     handle = psa_connect(TFM_SST_GET_SID, TFM_SST_GET_VERSION);
     if (!PSA_HANDLE_IS_VALID(handle)) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
+        return PSA_ERROR_GENERIC_ERROR;
     }
 
     status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
@@ -78,17 +80,15 @@
 
     psa_close(handle);
 
-    if (status != PSA_SUCCESS) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
-    }
+    *p_data_length = out_vec[0].len;
 
-    return err;
+    return status;
 }
 
-psa_ps_status_t psa_ps_get_info(psa_ps_uid_t uid, struct psa_ps_info_t *p_info)
+psa_status_t psa_ps_get_info(psa_storage_uid_t uid,
+                             struct psa_storage_info_t *p_info)
 {
     psa_status_t status;
-    psa_ps_status_t err;
     psa_handle_t handle;
 
     psa_invec in_vec[] = {
@@ -96,13 +96,12 @@
     };
 
     psa_outvec out_vec[] = {
-        { .base = &err,   .len = sizeof(err) },
         { .base = p_info, .len = sizeof(*p_info) }
     };
 
     handle = psa_connect(TFM_SST_GET_INFO_SID, TFM_SST_GET_INFO_VERSION);
     if (!PSA_HANDLE_IS_VALID(handle)) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
+        return PSA_ERROR_GENERIC_ERROR;
     }
 
     status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
@@ -110,63 +109,51 @@
 
     psa_close(handle);
 
-    if (status != PSA_SUCCESS) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
-    }
-
-    return err;
+    return status;
 }
 
-psa_ps_status_t psa_ps_remove(psa_ps_uid_t uid)
+psa_status_t psa_ps_remove(psa_storage_uid_t uid)
 {
     psa_status_t status;
-    psa_ps_status_t err;
     psa_handle_t handle;
 
     psa_invec in_vec[] = {
         { .base = &uid, .len = sizeof(uid) }
     };
 
-    psa_outvec out_vec[] = {
-        { .base = &err, .len = sizeof(err) }
-    };
 
     handle = psa_connect(TFM_SST_REMOVE_SID, TFM_SST_REMOVE_VERSION);
     if (!PSA_HANDLE_IS_VALID(handle)) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
+        return PSA_ERROR_GENERIC_ERROR;
     }
 
-    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec), out_vec,
-                      IOVEC_LEN(out_vec));
+    status = psa_call(handle, PSA_IPC_CALL, in_vec, IOVEC_LEN(in_vec),
+                      NULL, 0);
 
     psa_close(handle);
 
-    if (status != PSA_SUCCESS) {
-        return PSA_PS_ERROR_OPERATION_FAILED;
-    }
-
-    return err;
+    return status;
 }
 
-psa_ps_status_t psa_ps_create(psa_ps_uid_t uid, uint32_t size,
-                              psa_ps_create_flags_t create_flags)
+psa_status_t psa_ps_create(psa_storage_uid_t uid, size_t size,
+                           psa_storage_create_flags_t create_flags)
 {
     (void)uid;
     (void)size;
     (void)create_flags;
 
-    return PSA_PS_ERROR_NOT_SUPPORTED;
+    return PSA_ERROR_NOT_SUPPORTED;
 }
 
-psa_ps_status_t psa_ps_set_extended(psa_ps_uid_t uid, uint32_t data_offset,
-                                    uint32_t data_length, const void *p_data)
+psa_status_t psa_ps_set_extended(psa_storage_uid_t uid, size_t data_offset,
+                                 size_t data_length, const void *p_data)
 {
     (void)uid;
     (void)data_offset;
     (void)data_length;
     (void)p_data;
 
-    return PSA_PS_ERROR_NOT_SUPPORTED;
+    return PSA_ERROR_NOT_SUPPORTED;
 }
 
 uint32_t psa_ps_get_support(void)