diff --git a/quic/core/crypto/crypto_utils.h b/quic/core/crypto/crypto_utils.h
index 8cebf14..6c167f8 100644
--- a/quic/core/crypto/crypto_utils.h
+++ b/quic/core/crypto/crypto_utils.h
@@ -16,8 +16,10 @@
 #include "net/third_party/quiche/src/quic/core/crypto/crypto_handshake_message.h"
 #include "net/third_party/quiche/src/quic/core/crypto/crypto_protocol.h"
 #include "net/third_party/quiche/src/quic/core/crypto/quic_crypter.h"
+#include "net/third_party/quiche/src/quic/core/quic_connection_id.h"
 #include "net/third_party/quiche/src/quic/core/quic_packets.h"
 #include "net/third_party/quiche/src/quic/core/quic_time.h"
+#include "net/third_party/quiche/src/quic/core/quic_versions.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_export.h"
 #include "net/third_party/quiche/src/common/platform/api/quiche_string_piece.h"
 
@@ -95,6 +97,15 @@
                                        QuicConnectionId connection_id,
                                        CrypterPair* crypters);
 
+  // IETF QUIC Retry packets carry a retry integrity tag to detect packet
+  // corruption and make it harder for an attacker to spoof. This function
+  // checks whether a given retry packet is valid.
+  static bool ValidateRetryIntegrityTag(
+      ParsedQuicVersion version,
+      QuicConnectionId original_connection_id,
+      quiche::QuicheStringPiece retry_without_tag,
+      quiche::QuicheStringPiece integrity_tag);
+
   // Generates the connection nonce. The nonce is formed as:
   //   <4 bytes> current time
   //   <8 bytes> |orbit| (or random if |orbit| is empty)