MediaServicesStorageEncryption.cs

var _mediaServicesAccountName = "<アカウント名>";
var _mediaServicesAccountKey = "<アカウントキー>";
var _cachedCredentials = new MediaServicesCredentials(
       _mediaServicesAccountName,
       _mediaServicesAccountKey);

var _context = new CloudMediaContext(_cachedCredentials);
var file = "BigBuckBunny.mp4";

var assetName = Path.GetFileNameWithoutExtension(file);

// ポイントはここ。アセット作るときにオプションでStorageEncryptedを指定するだけ！
IAsset inputAsset = _context.Assets.Create(assetName, AssetCreationOptions.StorageEncrypted);

var assetFile = inputAsset.AssetFiles.Create(Path.GetFileName(file));

var policy = _context.AccessPolicies.Create(
                        assetName,
                        TimeSpan.FromDays(30),
                        AccessPermissions.Write | AccessPermissions.List);

var locator = _context.Locators.CreateLocator(LocatorType.Sas, inputAsset, policy);

assetFile.Upload(file);

locator.Delete();
policy.Delete();