本来对这个话题挺感兴趣的，点进来一看，除了少数楼之外全部都是散发戾气的无效信息。
Android 再不济也应该是可以通过推送来唤醒 app ，进而解密推送消息的。iOS 的话，手机搜了下，找到了条 2017 年的 Stackoverflow：
Apple released the UNNotificationServiceExtension last year, allowing developers to send fully-encrypted notification payloads through APNS and then let the app on the end-user's device itself do the decryption (or load any additional supporting data) before displaying the notification:
The UNNotificationServiceExtension class provides the entry point for a Notification Service app extension, which lets you customize the content of a remote notification before it is delivered to the user. A Notification Service app extension does not present any UI of its own. Instead, it is launched on demand when a notification of the appropriate type is delivered to the user’s device. You use this extension to modify the notification’s content or download content related to the extension. For example, you could use the extension to decrypt an encrypted data block or to download images associated with the notification.
https://stackoverflow.com/questions/32719476/how-secure-are-apple-apns-push-notifications所以也是能的。但是 telegram 的私密消息应该还是不提示内容的。
既然 LZ 是“非程序员”，那么如果 LZ 问的不是端到端加密（即允许推送消息被苹果 /Google/手机制造商搭建的推送服务器看到）的话，那么答案是肯定的，几乎肯定是有加密的。现在这个年代这种情况不太可能没有加密。