Export media_cas_packager_sdk

media_cas_packager_sdk/public/ecm_generator.h

@@ -0,0 +1,95 @@
+////////////////////////////////////////////////////////////////////////////////
+// Copyright 2018 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.
+////////////////////////////////////////////////////////////////////////////////
+
+#ifndef MEDIA_CAS_PACKAGER_SDK_PUBLIC_ECM_GENERATOR_H_
+#define MEDIA_CAS_PACKAGER_SDK_PUBLIC_ECM_GENERATOR_H_
+
+#include <stddef.h>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include <cstdint>
+#include "util/status.h"
+#include "media_cas_packager_sdk/internal/ecm.h"
+
+namespace widevine {
+namespace cas {
+
+// KeyParameters carries key information for a single encryption key.
+// Instances of this struct are owned by an EcmParameters struct.
+struct KeyParameters {
+  std::string key_id;
+  std::string key_data;
+  std::string wrapped_key_data;
+  std::string wrapped_key_iv;
+  std::vector<std::string> content_ivs;
+};
+
+// EcmParameters holds information that is needed by the EcmGenerator. It is
+// partially set up with data from a KeyGenerator (obtained via GenerateKey()).
+// IVs are added later.
+// TODO(user): may need a starting crypto period index.
+struct EcmParameters {
+  static constexpr int kDefaultIVSize = 8;
+  int iv_size = kDefaultIVSize;
+  bool current_key_even = true;
+  uint32_t current_key_index = 0;
+  std::string entitlement_key_id;
+  bool rotation_enabled = true;
+  uint32_t rotation_periods;
+  std::vector<KeyParameters> key_params;
+  uint16_t program_id;
+  uint64_t rotation_period_microseconds;
+  // For video, this is zero. For audio, this is the size of the audio frame,
+  // which is a constant in the audio track.
+  uint16_t offset = 0;
+};
+
+// ECM Generator for Widevine/MediaCAS entitled keys.
+class CasEcmGenerator {
+ public:
+  CasEcmGenerator() = default;
+  virtual ~CasEcmGenerator() = default;
+
+  virtual std::string GenerateEcm(const EcmParameters& params);
+
+  // Query the state of this ECM Generator
+  bool initialized() { return initialized_; }
+  bool rotation_enabled() { return rotation_enabled_; }
+
+  void set_ecm(std::unique_ptr<CasEcm> ecm) { ecm_ = std::move(ecm); }
+
+ private:
+  friend class CasEcmGeneratorTest;
+
+  util::Status ProcessEcmParameters(const EcmParameters& ecm_params,
+                                    std::vector<EntitledKeyInfo>* keys);
+
+  util::Status ProcessEcmParameters(const EcmParameters& ecm_params);
+  util::Status ValidateKeyId(const std::string& id);
+  util::Status ValidateKeyData(const std::string& key_data);
+  util::Status ValidateWrappedKeyIv(const std::string& iv);
+  util::Status ValidateIv(const std::string& iv, size_t required_size);
+  util::Status ValidateContentIv(const std::string& iv);
+  util::Status ValidateKeyParameters(const KeyParameters& key_params);
+
+  bool initialized_ = false;
+  uint32_t generation_ = 0;
+  bool rotation_enabled_ = false;
+  uint32_t current_key_index_ = 0;
+  bool current_key_even_ = true;
+  uint32_t content_iv_size_ = 0;
+  std::unique_ptr<CasEcm> ecm_;
+};
+
+}  // namespace cas
+}  // namespace widevine
+
+#endif  // MEDIA_CAS_PACKAGER_SDK_PUBLIC_ECM_GENERATOR_H_