diff --git a/src/lib.rs b/src/lib.rs
index 0fd58fc..3057ef0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,37 +5,37 @@ use tide::Next;
 use tide::Request;
 
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub enum Directive {
-    ChildSrc(Vec<String>),
-    ConnectSrc(Vec<String>),
-    DefaultSrc(Vec<String>),
-    FontSrc(Vec<String>),
-    FrameSrc(Vec<String>),
-    ImgSrc(Vec<String>),
-    ManifestSrc(Vec<String>),
-    MediaSrc(Vec<String>),
-    ObjectSrc(Vec<String>),
-    PrefetchSrc(Vec<String>),
-    ScriptSrc(Vec<String>),
-    ScriptSrcElem(Vec<String>),
-    ScriptSrcAttr(Vec<String>),
-    StyleSrc(Vec<String>),
-    StyleSrcElem(Vec<String>),
-    StyleSrcAttr(Vec<String>),
-    WorkerSrc(Vec<String>),
-    BaseUri(Vec<String>),
-    PluginTypes(Vec<String>),
+pub enum Directive<'a> {
+    ChildSrc(Vec<&'a str>),
+    ConnectSrc(Vec<&'a str>),
+    DefaultSrc(Vec<&'a str>),
+    FontSrc(Vec<&'a str>),
+    FrameSrc(Vec<&'a str>),
+    ImgSrc(Vec<&'a str>),
+    ManifestSrc(Vec<&'a str>),
+    MediaSrc(Vec<&'a str>),
+    ObjectSrc(Vec<&'a str>),
+    PrefetchSrc(Vec<&'a str>),
+    ScriptSrc(Vec<&'a str>),
+    ScriptSrcElem(Vec<&'a str>),
+    ScriptSrcAttr(Vec<&'a str>),
+    StyleSrc(Vec<&'a str>),
+    StyleSrcElem(Vec<&'a str>),
+    StyleSrcAttr(Vec<&'a str>),
+    WorkerSrc(Vec<&'a str>),
+    BaseUri(Vec<&'a str>),
+    PluginTypes(Vec<&'a str>),
     Sandbox(Sandbox),
-    FormAction(Vec<String>),
-    FrameAncestors(Vec<String>),
-    NavigateTo(Vec<String>),
+    FormAction(Vec<&'a str>),
+    FrameAncestors(Vec<&'a str>),
+    NavigateTo(Vec<&'a str>),
     ReportTo(String),
     RequireTrustedTypesFor(TrustedTypesTarget),
-    TrustedTypes(TrustedTypes),
+    TrustedTypes(TrustedTypes<'a>),
     UpgradeInsecureRequests,
 }
 
-impl Display for Directive {
+impl<'a> Display for Directive<'a> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
         match self {
             Self::ChildSrc(sources) => write!(f, "{}", sources.join(" ")),
@@ -127,15 +127,15 @@ impl Display for TrustedTypesTarget {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub enum TrustedTypes {
+pub enum TrustedTypes<'a> {
     None,
     Values {
-        policy_names: Vec<String>,
+        policy_names: Vec<&'a str>,
         allow_duplicates: bool,
     },
 }
 
-impl Display for TrustedTypes {
+impl<'a> Display for TrustedTypes<'a> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
         match self {
             Self::None => write!(f, "'none'"),