diff --git a/crypto/Makefile.am b/crypto/Makefile.am
index 50eb8f7..2c392dd 100644
--- a/crypto/Makefile.am
+++ b/crypto/Makefile.am
@@ -725,6 +725,7 @@ noinst_HEADERS += hidden/crypto_namespace.h
 noinst_HEADERS += hidden/openssl/asn1.h
 noinst_HEADERS += hidden/openssl/asn1t.h
 noinst_HEADERS += hidden/openssl/bio.h
+noinst_HEADERS += hidden/openssl/bn.h
 noinst_HEADERS += hidden/openssl/buffer.h
 noinst_HEADERS += hidden/openssl/cast.h
 noinst_HEADERS += hidden/openssl/chacha.h