diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 3b5aadb..b1f0c90 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -2276,4 +2276,8 @@
                                        const unsigned char *end );
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 
+int mbedtls_ssl_tls13_get_sig_alg_from_pk( mbedtls_ssl_context *ssl,
+                                           mbedtls_pk_context *own_key,
+                                           uint16_t *algorithm );
+
 #endif /* ssl_misc.h */
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index 17efa8c..842a708 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -866,9 +866,9 @@
 /*
  * STATE HANDLING: Output Certificate Verify
  */
-static int ssl_tls13_get_sig_alg_from_pk( mbedtls_ssl_context *ssl,
-                                          mbedtls_pk_context *own_key,
-                                          uint16_t *algorithm )
+int mbedtls_ssl_tls13_get_sig_alg_from_pk( mbedtls_ssl_context *ssl,
+                                           mbedtls_pk_context *own_key,
+                                           uint16_t *algorithm )
 {
     mbedtls_pk_type_t sig = mbedtls_ssl_sig_from_pk( own_key );
     /* Determine the size of the key */
@@ -1035,7 +1035,7 @@
      *    opaque signature<0..2^16-1>;
      *  } CertificateVerify;
      */
-    ret = ssl_tls13_get_sig_alg_from_pk( ssl, own_key, &algorithm );
+    ret = mbedtls_ssl_tls13_get_sig_alg_from_pk( ssl, own_key, &algorithm );
     if( ret != 0 || ! mbedtls_ssl_sig_alg_is_received( ssl, algorithm ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1,
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 22562a5..494208f 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -335,7 +335,8 @@
     return( 1 );
 }
 
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
 /*
  * Try picking a certificate for this ciphersuite,
  * return 0 on success and -1 on failure.
@@ -343,6 +344,8 @@
 static int ssl_tls13_pick_cert( mbedtls_ssl_context *ssl )
 {
     mbedtls_ssl_key_cert *cur, *list;
+    const uint16_t *sig_alg = ssl->handshake->received_sig_algs;
+    uint16_t own_sig_alg;
 
 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
     if( ssl->handshake->sni_key_cert != NULL )
@@ -357,37 +360,46 @@
         return( -1 );
     }
 
-    for( cur = list; cur != NULL; cur = cur->next )
+    for( ; *sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++ )
     {
-        MBEDTLS_SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate",
-                               cur->cert );
-
-        /*
-         * This avoids sending the client a cert it'll reject based on
-         * keyUsage or other extensions.
-         */
-        if( mbedtls_x509_crt_check_key_usage( cur->cert, MBEDTLS_X509_KU_DIGITAL_SIGNATURE ) != 0 )
+        for( cur = list; cur != NULL; cur = cur->next )
         {
-            MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: "
+            MBEDTLS_SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate",
+                                   cur->cert );
+
+            /*
+            * This avoids sending the client a cert it'll reject based on
+            * keyUsage or other extensions.
+            */
+            if( mbedtls_x509_crt_check_key_usage(
+                        cur->cert, MBEDTLS_X509_KU_DIGITAL_SIGNATURE ) != 0 ||
+                mbedtls_x509_crt_check_extended_key_usage(
+                        cur->cert, MBEDTLS_OID_SERVER_AUTH,
+                        MBEDTLS_OID_SIZE( MBEDTLS_OID_SERVER_AUTH ) ) != 0 )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: "
                                       "(extended) key usage extension" ) );
-            continue;
-        }
+                continue;
+            }
 
-        break;
-    }
-
-    /* Do not update ssl->handshake->key_cert unless there is a match */
-    if( cur != NULL )
-    {
-        ssl->handshake->key_cert = cur;
-        MBEDTLS_SSL_DEBUG_CRT( 3, "selected certificate chain, certificate",
+            if( ! mbedtls_ssl_tls13_get_sig_alg_from_pk(
+                ssl, &cur->cert->pk, &own_sig_alg ) &&
+                ( *sig_alg == own_sig_alg ) )
+            {
+                ssl->handshake->key_cert = cur;
+                MBEDTLS_SSL_DEBUG_CRT( 3, "selected certificate chain, certificate",
                                ssl->handshake->key_cert->cert );
-        return( 0 );
+                return( 0 );
+            }
+
+
+        }
     }
 
     return( -1 );
 }
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#endif /* MBEDTLS_X509_CRT_PARSE_C &&
+          MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
 
 /*
  *
@@ -755,14 +767,16 @@
     ssl->handshake->sni_name_len = 0;
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
     if( (ssl_tls13_pick_cert( ssl ) != 0) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
                             "no suitable certificate" ) );
         return( 0 );
     }
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#endif /* MBEDTLS_X509_CRT_PARSE_C &&
+          MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
 
     /* Update checksum with either
      * - The entire content of the CH message, if no PSK extension is present