1 files changed, 13 insertions, 0 deletions
diff --git a/ext/openssl/lib/openssl/hmac.rb b/ext/openssl/lib/openssl/hmac.rb
new file mode 100644
index 0000000000..3d4427611d
--- /dev/null
+++ b/ext/openssl/lib/openssl/hmac.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module OpenSSL
+  class HMAC
+    # Securely compare with another HMAC instance in constant time.
+    def ==(other)
+      return false unless HMAC === other
+      return false unless self.digest.bytesize == other.digest.bytesize
+
+      OpenSSL.fixed_length_secure_compare(self.digest, other.digest)
+    end
+  end
+end