diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index 3948ea6..32a4f2a 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -1572,10 +1572,9 @@
                                             unsigned char **psk,
                                             size_t *psk_len )
 {
-
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     psa_key_attributes_t key_attributes = PSA_KEY_ATTRIBUTES_INIT;
-    psa_status_t status;
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
 
     *psk_len = 0;
     *psk = NULL;
@@ -1585,16 +1584,12 @@
 
     status = psa_get_key_attributes( ssl->handshake->psk_opaque, &key_attributes );
     if( status != PSA_SUCCESS )
-    {
         return( psa_ssl_status_to_mbedtls( status ) );
-    }
 
     *psk_len = PSA_BITS_TO_BYTES( psa_get_key_bits( &key_attributes ) );
     *psk = mbedtls_calloc( 1, *psk_len );
     if( *psk == NULL )
-    {
         return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
-    }
 
     status = psa_export_key( ssl->handshake->psk_opaque,
                              (uint8_t *)*psk, *psk_len, psk_len );
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 2c4dd86..906ead7 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -47,9 +47,9 @@
 #include "ssl_debug_helpers.h"
 
 
-static const mbedtls_ssl_ciphersuite_t *ssl_tls13_get_ciphersuite_info_by_id(
+static const mbedtls_ssl_ciphersuite_t *ssl_tls13_validate_peer_ciphersuite(
                                       mbedtls_ssl_context *ssl,
-                                      uint16_t cipher_suite )
+                                      unsigned int cipher_suite )
 {
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
     if( ! mbedtls_ssl_tls13_cipher_suite_is_offered( ssl, cipher_suite ) )
@@ -235,8 +235,8 @@
         const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
 
         cipher_suite = MBEDTLS_GET_UINT16_BE( p, 0 );
-        ciphersuite_info = ssl_tls13_get_ciphersuite_info_by_id(
-                               ssl,cipher_suite );
+        ciphersuite_info = ssl_tls13_validate_peer_ciphersuite( ssl,
+                                                                cipher_suite );
         if( ciphersuite_info == NULL )
             continue;
 
@@ -416,9 +416,10 @@
                   mbedtls_psa_translate_md( ciphersuite_info->mac ) );
         if( ret != SSL_TLS1_3_OFFERED_PSK_MATCH )
         {
-            /* For the security rationale, handshake should be abort when binder
-             * value mismatch. See RFC 8446 section 4.2.11.2 and appendix E.6. */
-            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Binder is not matched." ) );
+            /* For security reasons, the handshake should be aborted when we
+             * fail to validate a binder value. See RFC 8446 section 4.2.11.2
+             * and appendix E.6. */
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Invalid binder." ) );
             MBEDTLS_SSL_DEBUG_RET( 1,
                 "ssl_tls13_offered_psks_check_binder_match" , ret );
             MBEDTLS_SSL_PEND_FATAL_ALERT(
@@ -1176,7 +1177,7 @@
         MBEDTLS_SSL_CHK_BUF_READ_PTR( p, cipher_suites_end, 2 );
 
         cipher_suite = MBEDTLS_GET_UINT16_BE( p, 0 );
-        ciphersuite_info = ssl_tls13_get_ciphersuite_info_by_id(
+        ciphersuite_info = ssl_tls13_validate_peer_ciphersuite(
                                ssl,cipher_suite );
         if( ciphersuite_info == NULL )
             continue;
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index d0193e4..3f1e01f 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -1860,10 +1860,12 @@
                 opt.tls13_kex_modes = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL;
             else if( strcmp( q, "all" ) == 0 )
                 opt.tls13_kex_modes = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_ALL;
-            /* `psk_or_ephemeral` exists in theory and is not recommended in practice.
-             * In server side, if needed extensions are received, psk or ephemeral
-             * mode will be set. Add this mode only for test purposes to improve
-             * test coverage.
+            /* The purpose of `psk_or_ephemeral` is to improve test coverage. That
+             * is not recommended in practice.
+             * `psk_or_ephemeral` exists in theory, we need this mode to test if
+             * this setting work correctly. With this key exchange setting, server
+             * should always perform `ephemeral` handshake. `psk` or `psk_ephermal`
+             * is not expected.
              */
             else if( strcmp( q, "psk_or_ephemeral" ) == 0 )
                 opt.tls13_kex_modes = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK |