diff --git a/cryptography/bindings/openssl/api.py b/cryptography/bindings/openssl/api.py
index 548a9e6..8445836 100644
--- a/cryptography/bindings/openssl/api.py
+++ b/cryptography/bindings/openssl/api.py
@@ -139,14 +139,14 @@
         assert res != 0
         return self.ffi.buffer(buf)[:outlen[0]]
 
-    def supports_hash(self, hashname):
+    def supports_hash(self, hash_cls):
         return (self.ffi.NULL !=
-                self.lib.EVP_get_digestbyname(hashname.encode("ascii")))
+                self.lib.EVP_get_digestbyname(hash_cls.name))
 
     def create_hash_context(self, hashobject):
         ctx = self.lib.EVP_MD_CTX_create()
         ctx = self.ffi.gc(ctx, self.lib.EVP_MD_CTX_destroy)
-        evp_md = self.lib.EVP_get_digestbyname(hashobject.name.encode("ascii"))
+        evp_md = self.lib.EVP_get_digestbyname(hashobject.name)
         assert evp_md != self.ffi.NULL
         res = self.lib.EVP_DigestInit_ex(ctx, evp_md, self.ffi.NULL)
         assert res != 0
diff --git a/cryptography/primitives/hashes.py b/cryptography/primitives/hashes.py
index d74287f..f5cf135 100644
--- a/cryptography/primitives/hashes.py
+++ b/cryptography/primitives/hashes.py
@@ -43,6 +43,6 @@
 
 
 class SHA1(BaseHash):
-    name = "sha1"
+    name = b"sha1"
     digest_size = 20
     block_size = 64
diff --git a/tests/primitives/test_hash_vectors.py b/tests/primitives/test_hash_vectors.py
index 8198b08..9a925e2 100644
--- a/tests/primitives/test_hash_vectors.py
+++ b/tests/primitives/test_hash_vectors.py
@@ -30,6 +30,6 @@
             "SHA1ShortMsg.rsp",
         ],
         hashes.SHA1,
-        only_if=lambda api: api.supports_hash("sha1"),
+        only_if=lambda api: api.supports_hash(hashes.SHA1),
         skip_message="Does not support SHA1",
     )
diff --git a/tests/primitives/test_hashes.py b/tests/primitives/test_hashes.py
index 1bc2e9e..4ad5c89 100644
--- a/tests/primitives/test_hashes.py
+++ b/tests/primitives/test_hashes.py
@@ -23,6 +23,6 @@
         hashes.SHA1,
         digest_size=20,
         block_size=64,
-        only_if=lambda api: api.supports_hash("sha1"),
+        only_if=lambda api: api.supports_hash(hashes.SHA1),
         skip_message="Does not support SHA1",
     )