diff --git a/quic/test_tools/test_certificates.cc b/quic/test_tools/test_certificates.cc
index d179d00..025a816 100644
--- a/quic/test_tools/test_certificates.cc
+++ b/quic/test_tools/test_certificates.cc
@@ -720,5 +720,15 @@
     kWildcardCertificatePrivateKeyRaw,
     sizeof(kWildcardCertificatePrivateKeyRaw));
 
+QUIC_CONST_INIT const char kTestEcPrivateKeyLegacyPem[] =
+    R"(-----BEGIN EC PARAMETERS-----
+BggqhkjOPQMBBw==
+-----END EC PARAMETERS-----
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIMdjXX0hg399DlccZuYFXPKq+dMGduXWmQYClDYJNDGroAoGCCqGSM49
+AwEHoUQDQgAENCuPQTywFI8hbsGo68AeN1KVWmd09buzlu/2CAtsJcNoECUmpVXH
+4dwvWMv6zWn9RJ5EzI72R/5FVcO485s5MQ==
+-----END EC PRIVATE KEY-----)";
+
 }  // namespace test
 }  // namespace quic
diff --git a/quic/test_tools/test_certificates.h b/quic/test_tools/test_certificates.h
index e7d3035..f617941 100644
--- a/quic/test_tools/test_certificates.h
+++ b/quic/test_tools/test_certificates.h
@@ -43,6 +43,9 @@
 QUIC_CONST_INIT extern const quiche::QuicheStringPiece
     kWildcardCertificatePrivateKey;
 
+// PEM-encoded P-256 private key using legacy OpenSSL encoding.
+QUIC_CONST_INIT extern const char kTestEcPrivateKeyLegacyPem[];
+
 }  // namespace test
 }  // namespace quic