diff --git a/tests/psa-client-server/psasim/src/psa_sim_crypto_server.c b/tests/psa-client-server/psasim/src/psa_sim_crypto_server.c
index da3adb0d3..30d4b26dc 100644
--- a/tests/psa-client-server/psasim/src/psa_sim_crypto_server.c
+++ b/tests/psa-client-server/psasim/src/psa_sim_crypto_server.c
@@ -2314,3 +2314,8 @@ psa_status_t psa_crypto_call(psa_msg_t msg)
 
     return ok ? PSA_SUCCESS : PSA_ERROR_GENERIC_ERROR;
 }
+
+void psa_crypto_close(void)
+{
+    psa_sim_serialize_reset();
+}
diff --git a/tests/psa-client-server/psasim/src/psa_sim_serialise.c b/tests/psa-client-server/psasim/src/psa_sim_serialise.c
index 9e8c38bb5..e326637a6 100644
--- a/tests/psa-client-server/psasim/src/psa_sim_serialise.c
+++ b/tests/psa-client-server/psasim/src/psa_sim_serialise.c
@@ -706,3 +706,9 @@ int psasim_deserialise_mbedtls_svc_key_id_t(uint8_t **pos,
 
     return 1;
 }
+
+void psa_sim_serialize_reset(void)
+{
+    memset(hash_operation_handles, 0, sizeof(hash_operation_handles));
+    memset(hash_operations, 0, sizeof(hash_operations));
+}
diff --git a/tests/psa-client-server/psasim/src/psa_sim_serialise.h b/tests/psa-client-server/psasim/src/psa_sim_serialise.h
index 9c69e65cc..721759585 100644
--- a/tests/psa-client-server/psasim/src/psa_sim_serialise.h
+++ b/tests/psa-client-server/psasim/src/psa_sim_serialise.h
@@ -54,6 +54,8 @@
  * don't contain pointers.
  */
 
+void psa_sim_serialize_reset(void);
+
 /** Return how much buffer space is needed by \c psasim_serialise_begin().
  *
  * \return                   The number of bytes needed in the buffer for
diff --git a/tests/psa-client-server/psasim/src/server.c b/tests/psa-client-server/psasim/src/server.c
index 77ce2694e..10ab5a287 100644
--- a/tests/psa-client-server/psasim/src/server.c
+++ b/tests/psa-client-server/psasim/src/server.c
@@ -54,6 +54,7 @@ int psa_server_main(int argc, char *argv[])
     int client_disconnected = 0;
     char mbedtls_version[18];
     extern psa_status_t psa_crypto_call(psa_msg_t msg);
+    extern psa_status_t psa_crypto_close(void);
 
     mbedtls_version_get_string_full(mbedtls_version);
     SERVER_PRINT("%s", mbedtls_version);
@@ -81,6 +82,7 @@ int psa_server_main(int argc, char *argv[])
                         SERVER_PRINT("Got a disconnection message");
                         ret = PSA_SUCCESS;
                         client_disconnected = 1;
+                        psa_crypto_close();
                         break;
                     default:
                         SERVER_PRINT("Got an IPC call of type %d", msg.type);