Replace hardcoded parameters

common/rot_id_util.h

@@ -0,0 +1,45 @@
+////////////////////////////////////////////////////////////////////////////////
+// Copyright 2019 Google LLC.
+//
+// This software is licensed under the terms defined in the Widevine Master
+// License Agreement. For a copy of this agreement, please contact
+// widevine-licensing@google.com.
+////////////////////////////////////////////////////////////////////////////////
+//
+// Description:
+//   Helper methods for the Root of Trust Id.
+
+#ifndef COMMON_ROT_ID_UTIL_H_
+#define COMMON_ROT_ID_UTIL_H_
+
+#include <memory>
+#include <vector>
+
+#include <cstdint>
+#include "common/ec_key.h"
+#include "common/local_ec_key_source.h"
+
+namespace widevine {
+
+// Helper function that compares the |rot_id_hash| to a hash of each of the
+// |revoked_ids|. The |revoked_ids| are the unique id hash (aka inner hash)
+// values as defined in the spec at go/wv-kb-id. The |encrypted_unique_id| and
+// |system_id| are used to compute the hash of each of the |revoked_ids|.
+// Returns true if any of the revoked_ids match.
+bool IsRotIdRevoked(const std::string& encrypted_unique_id, uint32_t system_id,
+                    const std::string& rot_id_hash,
+                    const std::vector<std::string>& revoked_ids);
+
+// Helper function that generates the hash for the ROT id from the
+// |unique_id_hash|, the |system_id| and the |salt|. |salt| is typically an
+// encrypted unique id. Since we use an ephemeral eliptic curve key as part of
+// the encrypted unique id, the value is effectively random can be used as a
+// salt.
+// Returns the hash value on success.
+// If |salt| or |unique_id_hash| are empty, this will return an empty
+// string.
+std::string GenerateRotIdHash(const std::string& salt, uint32_t system_id,
+                              const std::string& unique_id_hash);
+
+}  // namespace widevine
+#endif  // COMMON_ROT_ID_UTIL_H_