diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py
index a212df4..c70446b 100644
--- a/tests/hazmat/backends/test_openssl.py
+++ b/tests/hazmat/backends/test_openssl.py
@@ -103,5 +103,5 @@
         backend._lib.SSL_CTX_free(ctx)
 
     def test_evp_ciphers_registered(self):
-        cipher = backend._lib.EVP_get_cipherbyname("aes-256-cbc")
+        cipher = backend._lib.EVP_get_cipherbyname(b"aes-256-cbc")
         assert cipher != backend._ffi.NULL