diff --git a/src/auth.cc b/src/auth.cc
index 1aa9ba0..1ac7fc4 100644
--- a/src/auth.cc
+++ b/src/auth.cc
@@ -29,12 +29,12 @@ struct AuthParse_t
 {
    int ok;
    enum AuthParseHTTPAuthType_t type;
-   const char *realm;
-   const char *nonce;
-   const char *opaque;
+   std::optional< std::string > realm;
+   std::optional< std::string > nonce;
+   std::optional< std::string > opaque;
    int stale;
    enum AuthParseDigestAlgorithm_t algorithm;
-   const char *domain;
+   std::optional< std::string > domain;
    enum AuthParseDigestQOP_t qop;
 };
 
@@ -45,10 +45,11 @@ struct AuthHost_t
    Dlist *realms;
 };
 
-typedef struct {
+struct AuthDialogData_t
+{
    const AuthParse_t *auth_parse;
    const DilloUrl *url;
-} AuthDialogData_t;
+};
 
 /**
  *  Local data
@@ -60,25 +61,15 @@ static AuthParse_t *Auth_parse_new(void)
    AuthParse_t *auth_parse = std::make_unique< AuthParse_t >().release();
    auth_parse->ok = 0;
    auth_parse->type = TYPENOTSET;
-   auth_parse->realm = NULL;
-   auth_parse->nonce = NULL;
-   auth_parse->opaque = NULL;
    auth_parse->stale = 0;
    auth_parse->algorithm = ALGORITHMNOTSET;
-   auth_parse->domain = NULL;
    auth_parse->qop = QOPNOTSET;
    return auth_parse;
 }
 
 static void Auth_parse_free(AuthParse_t *auth_parse)
 {
-   if (auth_parse) {
-      dFree((void *)auth_parse->realm);
-      dFree((void *)auth_parse->nonce);
-      dFree((void *)auth_parse->opaque);
-      dFree((void *)auth_parse->domain);
-      delete auth_parse;
-   }
+	delete auth_parse;
 }
 
 static int Auth_path_is_inside(const char *path1, const char *path2, int len)
@@ -225,7 +216,7 @@ static int Auth_parse_basic_challenge_cb(AuthParse_t *auth_parse, char *token,
 {
    if (dStrAsciiCasecmp("realm", token) == 0) {
       if (!auth_parse->realm)
-         auth_parse->realm = dStrdup(value);
+         auth_parse->realm = value;
       return 0; /* end parsing */
    } else
       MSG("Auth_parse_basic_challenge_cb: Ignoring unknown parameter: %s = "
@@ -239,13 +230,13 @@ static int Auth_parse_digest_challenge_cb(AuthParse_t *auth_parse, char *token,
    const char *const fn = "Auth_parse_digest_challenge_cb";
 
    if (!dStrAsciiCasecmp("realm", token) && !auth_parse->realm)
-      auth_parse->realm = dStrdup(value);
+      auth_parse->realm = value;
    else if (!strcmp("domain", token) && !auth_parse->domain)
-      auth_parse->domain = dStrdup(value);
+      auth_parse->domain = value;
    else if (!strcmp("nonce", token)  && !auth_parse->nonce)
-      auth_parse->nonce = dStrdup(value);
+      auth_parse->nonce = value;
    else if (!strcmp("opaque", token) && !auth_parse->opaque)
-      auth_parse->opaque = dStrdup(value);
+      auth_parse->opaque = value;
    else if (strcmp("stale", token) == 0) {
       if (dStrAsciiCasecmp("true", value) == 0)
          auth_parse->stale = 1;
@@ -514,7 +505,7 @@ static int Auth_do_auth_required(const AuthParse_t *auth_parse,
     * we will re-authenticate.
     */
    if ((host = Auth_host_by_url(url)) &&
-       (realm = Auth_realm_by_name(host, auth_parse->realm))) {
+       (realm = Auth_realm_by_name(host, auth_parse->realm.value().c_str()))) {
       if (!Auth_realm_includes_path(realm, URL_PATH(url))) {
          _MSG("Auth_do_auth_required: updating realm '%s' with URL '%s'\n",
               auth_parse->realm, URL_STR(url));
@@ -525,7 +516,7 @@ static int Auth_do_auth_required(const AuthParse_t *auth_parse,
       if (auth_parse->type == DIGEST && auth_parse->stale) {
          /* we do have valid credentials but our nonce is old */
          dFree((void *)realm->nonce);
-         realm->nonce = dStrdup(auth_parse->nonce);
+         realm->nonce = dStrdup(auth_parse->nonce.value().c_str());
          return 0;
       }
    }
@@ -557,9 +548,9 @@ static void Auth_do_auth_dialog_cb(const char *user, const char *password,
    }
 
    /* find or create the realm */
-   if (!(realm = Auth_realm_by_name(host, data->auth_parse->realm))) {
+   if (!(realm = Auth_realm_by_name(host, data->auth_parse->realm.value().c_str()))) {
       realm = dNew0(AuthRealm_t, 1);
-      realm->name = dStrdup(data->auth_parse->realm);
+      realm->name = dStrdup(data->auth_parse->realm.value().c_str());
       realm->paths = dList_new(1);
       dList_append(host->realms, realm);
    }
@@ -584,12 +575,12 @@ static void Auth_do_auth_dialog_cb(const char *user, const char *password,
       realm->username = dStrdup(user);
       realm->nonce_count = 0;
       dFree(realm->nonce);
-      realm->nonce = dStrdup(data->auth_parse->nonce);
+      realm->nonce = dStrdup(data->auth_parse->nonce.value().c_str());
       dFree(realm->opaque);
-      realm->opaque = dStrdup(data->auth_parse->opaque);
+      realm->opaque = dStrdup(data->auth_parse->opaque.value().c_str());
       realm->algorithm = data->auth_parse->algorithm;
       dFree(realm->domain);
-      realm->domain = dStrdup(data->auth_parse->domain);
+      realm->domain = dStrdup(data->auth_parse->domain.value().c_str());
       realm->qop = data->auth_parse->qop;
       dFree(realm->cnonce);
       if (realm->qop != QOPNOTSET)
@@ -624,13 +615,13 @@ static int Auth_do_auth_dialog(const AuthParse_t *auth_parse,
    msg = dStrconcat("The server at ", URL_HOST(url), " requires a username"
                     " and password for  \"", auth_parse->realm, "\".\n\n"
                     "Authentication scheme: ", typestr, NULL);
-   data = dNew(AuthDialogData_t, 1);
+   data = std::make_unique< AuthDialogData_t >().release();
    data->auth_parse = auth_parse;
    data->url = a_Url_dup(url).release();
    ret = a_Dialog_user_password(title, msg, Auth_do_auth_dialog_cb, data);
    dFree(title); dFree(msg);
    delete const_cast< DilloUrl * >( data->url );
-   dFree(data);
+   delete data;
    return ret;
 }