The ACLU has a good overview (https://www.aclu.org/news/privacy-technology/police-should-not-be-allowed-to-compel-our-cell-phone-passwords https://www.aclu.org/

The ACLU has a good overview (https://www.aclu.org/news/privacy-technology/police-should-not-be-allowed-to-compel-our-cell-phone-passwords https://www.aclu.org/news/privacy-technology/police-should-n...). A number of state-level supreme courts have ruled that the protection you're describing exists, but others have ruled against it, and on the federal level AFAIK only the DC Circuit has made a clear ruling about it.