NEW YORK (NYTIMES) - It looked like a calculator app. But it was actually spyware recording my every keystroke - the type of data that would give a stalker unfettered access to my private life.

That is what I concluded after downloading the free app Flash Keylogger onto an Android smartphone last month. The app described itself as a tool to monitor the online activities of family members by logging what they type. Once it was installed from Google's official app store, its icon could be changed to that of a calculator or calendar app. In my tests, the app documented all of my typing, including Web searches, text messages and e-mails.