diff --git a/lib/hcrypto/test_engine_dso.c b/lib/hcrypto/test_engine_dso.c
index f0cb7d417..e3d7d1bc5 100644
--- a/lib/hcrypto/test_engine_dso.c
+++ b/lib/hcrypto/test_engine_dso.c
@@ -199,7 +199,7 @@ main(int argc, char **argv)
 	RSA *rsa;
 	FILE *f;
 	
-	f = fopen(rsa_flag, "r");
+	f = fopen(rsa_flag, "rb");
 	if (f == NULL)
 	    err(1, "could not open file %s", rsa_flag);
 	
diff --git a/lib/hcrypto/test_rsa.c b/lib/hcrypto/test_rsa.c
index 510f951b1..1f7c0efab 100644
--- a/lib/hcrypto/test_rsa.c
+++ b/lib/hcrypto/test_rsa.c
@@ -157,7 +157,7 @@ read_key(ENGINE *engine, const char *rsa_key)
     RSA *rsa;
     FILE *f;
 
-    f = fopen(rsa_key, "r");
+    f = fopen(rsa_key, "rb");
     if (f == NULL)
 	err(1, "could not open file %s", rsa_key);
     rk_cloexec_file(f);