diff --git a/quic/core/crypto/null_decrypter.cc b/quic/core/crypto/null_decrypter.cc
index e89fecc..af0a886 100644
--- a/quic/core/crypto/null_decrypter.cc
+++ b/quic/core/crypto/null_decrypter.cc
@@ -80,6 +80,10 @@
   return 0;
 }
 
+size_t NullDecrypter::GetNoncePrefixSize() const {
+  return 0;
+}
+
 size_t NullDecrypter::GetIVSize() const {
   return 0;
 }