--- /dev/null
+/* Copyright (c) 2018, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#ifndef OPENSSL_HEADER_CRYPTO_FIPSMODULE_TLS_INTERNAL_H
+#define OPENSSL_HEADER_CRYPTO_FIPSMODULE_TLS_INTERNAL_H
+
+#include <openssl/base.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+
+// tls1_prf calculates |out_len| bytes of the TLS PDF, using |digest|, and
+// writes them to |out|. It returns one on success and zero on error.
+OPENSSL_EXPORT int CRYPTO_tls1_prf(const EVP_MD *digest,
+ uint8_t *out, size_t out_len,
+ const uint8_t *secret, size_t secret_len,
+ const char *label, size_t label_len,
+ const uint8_t *seed1, size_t seed1_len,
+ const uint8_t *seed2, size_t seed2_len);
+
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif // OPENSSL_HEADER_CRYPTO_FIPSMODULE_TLS_INTERNAL_H