Internet-based personal assistants are promising devices combining voice control and search technologies to pull out relevant information to domestic users. They are expected to assist in a smart way to household activities, such as to schedule meetings, nd locations, reporting of cultural events, sending of messages and a lot more. The information collected by these devices, including personalized lifelogs about their corresponding users, is likely to be stored by well-established Internet players related to web search engines and social media. This can lead to serious privacy risks. The issue of protecting the identity of domestic users and their sensitive data must be tackled at design time, to promptly mitigate privacy threats. Towards this end, this paper proposes a protection scheme that jointly handles the aforementioned issues by combining log anonymization and sanitizable signatures