diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 08741bc..8628384 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1901,40 +1901,40 @@
 /*
  * Helper functions around key exchange modes.
  */
-static inline unsigned mbedtls_ssl_conf_tls13_check_kex_modes(mbedtls_ssl_context *ssl,
-                                                              int kex_mode_mask)
+static inline int mbedtls_ssl_conf_tls13_is_kex_mode_enabled(mbedtls_ssl_context *ssl,
+                                                             int kex_mode_mask)
 {
-    return (ssl->conf->tls13_kex_modes & kex_mode_mask) == 0;
+    return (ssl->conf->tls13_kex_modes & kex_mode_mask) != 0;
 }
 
 static inline int mbedtls_ssl_conf_tls13_psk_enabled(mbedtls_ssl_context *ssl)
 {
-    return !mbedtls_ssl_conf_tls13_check_kex_modes(ssl,
-                                                   MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK);
+    return mbedtls_ssl_conf_tls13_is_kex_mode_enabled(ssl,
+                                                      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK);
 }
 
 static inline int mbedtls_ssl_conf_tls13_psk_ephemeral_enabled(mbedtls_ssl_context *ssl)
 {
-    return !mbedtls_ssl_conf_tls13_check_kex_modes(ssl,
-                                                   MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL);
+    return mbedtls_ssl_conf_tls13_is_kex_mode_enabled(ssl,
+                                                      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL);
 }
 
 static inline int mbedtls_ssl_conf_tls13_ephemeral_enabled(mbedtls_ssl_context *ssl)
 {
-    return !mbedtls_ssl_conf_tls13_check_kex_modes(ssl,
-                                                   MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL);
+    return mbedtls_ssl_conf_tls13_is_kex_mode_enabled(ssl,
+                                                      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL);
 }
 
 static inline int mbedtls_ssl_conf_tls13_some_ephemeral_enabled(mbedtls_ssl_context *ssl)
 {
-    return !mbedtls_ssl_conf_tls13_check_kex_modes(ssl,
-                                                   MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ALL);
+    return mbedtls_ssl_conf_tls13_is_kex_mode_enabled(ssl,
+                                                      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ALL);
 }
 
 static inline int mbedtls_ssl_conf_tls13_some_psk_enabled(mbedtls_ssl_context *ssl)
 {
-    return !mbedtls_ssl_conf_tls13_check_kex_modes(ssl,
-                                                   MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL);
+    return mbedtls_ssl_conf_tls13_is_kex_mode_enabled(ssl,
+                                                      MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL);
 }
 
 #if defined(MBEDTLS_SSL_SRV_C) && \
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 7844ced..c2cd18d 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -684,7 +684,7 @@
     mbedtls_ssl_session *session = ssl->session_negotiate;
     return ssl->handshake->resume &&
            session != NULL && session->ticket != NULL &&
-           !mbedtls_ssl_conf_tls13_check_kex_modes(
+           mbedtls_ssl_conf_tls13_is_kex_mode_enabled(
         ssl, mbedtls_ssl_session_get_ticket_flags(
             session, MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL));
 }
@@ -1879,7 +1879,7 @@
             goto cleanup;
     }
 
-    if (mbedtls_ssl_conf_tls13_check_kex_modes(
+    if (!mbedtls_ssl_conf_tls13_is_kex_mode_enabled(
             ssl, handshake->key_exchange_mode)) {
         ret = MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
         MBEDTLS_SSL_DEBUG_MSG(