Add Provisioning 4 support

Widevine provisioning 4 support is added in this patch.

plugin/include/service_certificate.h

@@ -0,0 +1,64 @@
+// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+#ifndef WIDEVINE_CAS_SERVICE_CERTIFICATE_H_
+#define WIDEVINE_CAS_SERVICE_CERTIFICATE_H_
+
+#include <memory>
+#include <string>
+
+#include "cas_status.h"
+#include "license_protocol.pb.h"
+#include "privacy_crypto.h"
+
+namespace wvcas {
+
+// Service Certificates are used to encrypt the ClientIdentification message
+// that is part of Device Provisioning, License, Renewal, and Release requests.
+class ServiceCertificate {
+ public:
+  ServiceCertificate() = default;
+  virtual ~ServiceCertificate() {}
+
+  // Set up a new service certificate.
+  // Accept a serialized video_widevine::SignedDrmDeviceCertificate message.
+  virtual CasStatus Init(const std::string& signed_certificate);
+
+  bool HasSignedCertificate() const { return !signed_certificate_.empty(); }
+  const std::string& signed_certificate() const { return signed_certificate_; }
+  const std::string& provider_id() const { return provider_id_; }
+
+  // Encrypt the ClientIdentification message for a provisioning or
+  // licensing request.  Encryption is performed using the current
+  // service certificate.  Return a failure if the service certificate is
+  // not present, not valid, or if some other error occurs.
+  // The routine should not be called if privacy mode is off or if the
+  // certificate is empty.
+  CasStatus EncryptClientId(
+      const video_widevine::ClientIdentification* clear_client_id,
+      video_widevine::EncryptedClientIdentification* encrypted_client_id) const;
+
+ private:
+  // Encrypt data using RSA with OAEP padding.
+  // |plaintext| is the data to be encrypted. |ciphertext| is a pointer to a
+  // string to contain the decrypted data on return, and may not be null.
+  // returns NO_ERROR if successful or an appropriate error code otherwise.
+  virtual CasStatus EncryptRsaOaep(const std::string& plaintext,
+                                   std::string* ciphertext) const;
+
+  // Proto serialized SignedDrmCertificate.
+  // Verified by Init() to be valid.
+  std::string signed_certificate_;
+
+  // Certificate serial number.
+  std::string serial_number_;
+
+  // Provider ID, extracted from certificate message.
+  std::string provider_id_;
+
+  // Public key.
+  std::unique_ptr<RsaPublicKey> public_key_;
+};  // class ServiceCertificate
+
+}  // namespace wvcas
+#endif  // WIDEVINE_CAS_SERVICE_CERTIFICATE_H_