diff --git a/quinn-proto/src/crypto.rs b/quinn-proto/src/crypto.rs
index e8b7c04df..452e700a5 100644
--- a/quinn-proto/src/crypto.rs
+++ b/quinn-proto/src/crypto.rs
@@ -29,8 +29,6 @@ pub(crate) mod types;
 
 /// A cryptographic session (commonly TLS)
 pub trait Session: Send + Sized {
-    /// Cryptographic identity of the peer
-    type Identity: Sized;
     /// Type used to hold configuration for client sessions
     type ClientConfig: ClientConfig<Self>;
     /// Type used to sign various values
@@ -53,7 +51,7 @@ pub trait Session: Send + Sized {
     fn handshake_data(&self) -> Option<Box<dyn Any>>;
 
     /// Get the peer's identity, if available
-    fn peer_identity(&self) -> Option<Self::Identity>;
+    fn peer_identity(&self) -> Option<Box<dyn Any>>;
 
     /// Get the 0-RTT keys if available (clients only)
     ///
diff --git a/quinn-proto/src/crypto/rustls.rs b/quinn-proto/src/crypto/rustls.rs
index 724ba42e4..238c020c7 100644
--- a/quinn-proto/src/crypto/rustls.rs
+++ b/quinn-proto/src/crypto/rustls.rs
@@ -36,7 +36,6 @@ impl TlsSession {
 }
 
 impl crypto::Session for TlsSession {
-    type Identity = CertificateChain;
     type ClientConfig = Arc<rustls::ClientConfig>;
     type HmacKey = hmac::Key;
     type HandshakeTokenKey = hkdf::Prk;
@@ -71,8 +70,10 @@ impl crypto::Session for TlsSession {
         }))
     }
 
-    fn peer_identity(&self) -> Option<CertificateChain> {
-        self.inner.peer_certificates().map(|v| v.to_vec().into())
+    fn peer_identity(&self) -> Option<Box<dyn Any>> {
+        self.inner
+            .peer_certificates()
+            .map(|v| -> Box<dyn Any> { Box::new(CertificateChain::from(v.to_vec())) })
     }
 
     fn early_crypto(&self) -> Option<(Self::HeaderKey, Self::PacketKey)> {
diff --git a/quinn/src/connection.rs b/quinn/src/connection.rs
index 187e123a7..a7c441f3a 100644
--- a/quinn/src/connection.rs
+++ b/quinn/src/connection.rs
@@ -478,7 +478,11 @@ where
     }
 
     /// Cryptographic identity of the peer
-    pub fn peer_identity(&self) -> Option<S::Identity> {
+    ///
+    /// The dynamic type returned is determined by the configured
+    /// [`Session`](proto::crypto::Session). For the default `rustls` session, the return value can
+    /// be [`downcast`](Box::downcast) to a [`CertificateChain`](crate::CertificateChain).
+    pub fn peer_identity(&self) -> Option<Box<dyn Any>> {
         self.0
             .lock("peer_identity")
             .inner