Add Provisioning 4 support

Widevine provisioning 4 support is added in this patch.

plugin/include/privacy_crypto.h

@@ -0,0 +1,86 @@
+// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+//
+// Description:
+//   Declaration of classes representing AES and RSA public keys used
+//   for signature verification and encryption.
+//
+// AES encryption details:
+//   Algorithm: AES-CBC
+//
+// RSA signature details:
+//   Algorithm: RSASSA-PSS
+//   Hash algorithm: SHA1
+//   Mask generation function: mgf1SHA1
+//   Salt length: 20 bytes
+//   Trailer field: 0xbc
+//
+// RSA encryption details:
+//   Algorithm: RSA-OAEP
+//   Mask generation function: mgf1SHA1
+//   Label (encoding paramter): empty string
+//
+#ifndef WIDEVINE_CAS_PRIVACY_CRYPTO_H_
+#define WIDEVINE_CAS_PRIVACY_CRYPTO_H_
+
+#include <cstdint>
+#include <string>
+
+namespace wvcas {
+
+class AesCbcKey {
+ public:
+  AesCbcKey();
+  ~AesCbcKey();
+
+  bool Init(const std::string& key);
+  bool Encrypt(const std::string& in, const std::string& iv, std::string* out,
+               bool has_padding = true);
+  bool Decrypt(const std::string& in, const std::string& iv, std::string* out,
+               bool has_padding = true);
+
+ private:
+  std::string key_;
+};  // class AesCbcKey
+
+class RsaPublicKey {
+ public:
+  RsaPublicKey();
+  ~RsaPublicKey();
+
+  // Initializes an RsaPublicKey object using a DER encoded PKCS#1 RSAPublicKey
+  bool Init(const std::string& serialized_key);
+
+  // Encrypt a message using RSA-OAEP. Caller retains ownership of all
+  // parameters. Returns true if successful, false otherwise.
+  bool Encrypt(const std::string& plaintext, std::string* ciphertext);
+
+  // Verify RSASSA-PSS signature. Caller retains ownership of all parameters.
+  // Returns true if validation succeeds, false otherwise.
+  bool VerifySignature(const std::string& message,
+                       const std::string& signature);
+
+ private:
+  std::string serialized_key_;
+};  // class RsaPublicKey
+
+/**
+ * Extracts an integer value from the extensions in a certificate.
+ * @param cert A PKCS7 encoded X.509 certificate chain.
+ * @param extension_oid The ID of the extension to get.
+ * @param cert_index The zero-based index of the certificate in the chain to
+ *   fetch from.
+ * @param value [OUT] Will contain the extracted value.
+ * @return True on success, false on error.
+ */
+bool ExtractExtensionValueFromCertificate(const std::string& cert,
+                                          const std::string& extension_oid,
+                                          size_t cert_index, uint32_t* value);
+
+std::string Md5Hash(const std::string& data);
+std::string Sha1Hash(const std::string& data);
+std::string Sha256Hash(const std::string& data);
+std::string Sha512Hash(const std::string& data);
+}  // namespace wvcas
+#endif  // WIDEVINE_CAS_PRIVACY_CRYPTO_H_