Merge branch 'master' of https://widevine-partner.googlesource.com/media_cas_packager_sdk_source into moe_writing_branch_from_fcdd9fa38cb2674e34790e8360af4722a09a0927

example/wv_cas_ecm_example.cc

@@ -0,0 +1,55 @@
+////////////////////////////////////////////////////////////////////////////////
+// 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.
+////////////////////////////////////////////////////////////////////////////////
+
+// Example of how to use the wv_cas_ecm library.
+
+#include <string>
+
+#include "gflags/gflags.h"
+#include "glog/logging.h"
+#include "absl/strings/escaping.h"
+#include "absl/strings/str_cat.h"
+#include "util/status.h"
+#include "media_cas_packager_sdk/public/wv_cas_ecm.h"
+
+const char kEvenKey[] = "even_content_key";                         // 16 bytes
+const char kEvenContentIv8Bytes[] = "evencont";                     // 8 bytes
+const char kOddKey[] = "odd_content_key.";                          // 16 bytes
+const char kOddContentIv8Bytes[] = "oddcont.";                      // 8 bytes
+const char kEntitlementKeyId[] = "ent_key_id......";                // 16 bytes
+const char kEntitlementKey[] = "entitlement_key.................";  // 32 bytes
+
+int main(int argc, char **argv) {
+  gflags::ParseCommandLineFlags(&argc, &argv, true);
+
+  widevine::cas::WvCasEcm wv_cas_ecm;
+  auto status = wv_cas_ecm.Initialize(/* content_iv_size= */ 16,
+                                      /* key_rotation_enabled= */ true,
+                                      /* crypto_mode= */ 1);
+  if (!status.ok()) {
+    LOG(FATAL) << "Failed to initialize WV CAS ECM, error: " << status;
+  }
+  std::string ecm;
+  status = wv_cas_ecm.GenerateEcm(
+      /* even_key= */ kEvenKey,
+      /* even_content_iv= */
+      absl::StrCat(kEvenContentIv8Bytes, kEvenContentIv8Bytes),
+      /* odd_key= */ kOddKey,
+      /* odd_content_iv= */
+      absl::StrCat(kOddContentIv8Bytes, kOddContentIv8Bytes),
+      /* entitlement_key_id= */ kEntitlementKeyId,
+      /* entitlement_key= */ kEntitlementKey, &ecm);
+  if (!status.ok()) {
+    LOG(FATAL) << "Failed to generate WV CAS ECM, error: " << status;
+  } else {
+    LOG(INFO) << "Generated WV CAS ECM (in hex): "
+              << absl::BytesToHexString(ecm);
+  }
+
+  return 0;
+}

media_cas_packager_sdk/public/wv_cas_ecm.h

@@ -38,8 +38,9 @@ class WvCasEcm {
   //
   // Args:
   // - |content_iv_size| iv size in bytes for encrypting the content,
-  //   only support 8 bytes now
+  //   only support 8 bytes or 16 bytes
-  //   TODO(user): Double-check with jfore@ regarding only support 8 bytes.
+  //   When using 8 bytes content_iv, we assume additional 8 bytes of '\x00' are
+  //   appended to the iv to form a 16 bytes AES IV when content is encrypted.
   // - |key_rotation_enabled| whether key rotation is enabled,
   //   if this is 'true' only subsequent call to GenerateEcm will be allowed,
   //   if this is 'false' only subsequent call to GenerateSingleKeyEcm will
@@ -47,7 +48,6 @@ class WvCasEcm {
   // - |crypto_mode| crypto mode for encrypting content,
   //   kCryptoModeCbc = 0, kCryptoModeCtr = 1
   //   only CTR is supported by Widevine CAS plugin for now
-  //   TODO(user): Check with jfore@ regarding supporting kCryptoModeCbc.
   //
   // Returns:
   // - A status indicating whether there was any error during initialization
@@ -62,10 +62,8 @@ class WvCasEcm {
   //
   // Args:
   // - |even_key| clear even content key
-  // - |even_wrapping_iv| iv used when encrypting |even_key| in the ECM
   // - |even_content_iv| iv used along with |even_key| for encrypting content
   // - |odd_key| clear odd content key
-  // - |odd_wrapping_iv| iv used when encrypting |odd_key| in the ECM
   // - |odd_content_iv| iv used along with |odd_key| for encrypting content
   // - |entitlement_key_id| key id for |entitlement_key|
   // - |entitlement_key| entitlement key used to encrypt even and odd keys
@@ -77,15 +75,10 @@ class WvCasEcm {
   // Note:
   // - The same |entitlement_key| will be used to encrypt both |even_key|
   //   and |odd_key| in the ECM
-  // - Currently, we only allow |even_content_iv| and |odd_content_iv|
+  // - Size of |even_content_iv| and |odd_content_iv| must match
-  //   to be of size 8 bytes, so we assume the encryptor would append suffix
+  //   |content_iv_size| set during initialization
-  //   {'\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00'}
-  //   to |even_content_iv| and |odd_content_iv| to obtain a 16 bytes IV
-  //   before encrypting the content
   util::Status GenerateEcm(const std::string& even_key,
-                           const std::string& even_wrapping_iv,
                            const std::string& even_content_iv, const std::string& odd_key,
-                           const std::string& odd_wrapping_iv,
                            const std::string& odd_content_iv,
                            const std::string& entitlement_key_id,
                            const std::string& entitlement_key, std::string* ecm);
@@ -95,7 +88,6 @@ class WvCasEcm {
   //
   // Args:
   // - |even_key| clear even content key
-  // - |even_wrapping_iv| iv used when encrypting |even_key| in the ECM
   // - |even_content_iv| iv used along with |even_key| for encrypting content
   // - |entitlement_key_id| key id for |entitlement_key|
   // - |entitlement_key| entitlement key used to encrypt even key
@@ -105,14 +97,9 @@ class WvCasEcm {
   // - A status indicating whether there was any error during processing
   //
   // Note:
-  //
+  // - Size of |even_content_iv| and |odd_content_iv| must match
-  // - Currently, we only allow |even_content_iv|
+  //   |content_iv_size| set during initialization
-  //   to be of size 8 bytes, so we assume the encryptor would append suffix
-  //   {'\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00'}
-  //   to |even_content_iv| to obtain a 16 bytes IV
-  //   before encrypting the content
   util::Status GenerateSingleKeyEcm(const std::string& even_key,
-                                    const std::string& even_wrapping_iv,
                                     const std::string& even_content_iv,
                                     const std::string& entitlement_key_id,
                                     const std::string& entitlement_key, std::string* ecm);