Per our Privacy Policy, we do not give out user information except as required by valid legal process. (law.stackexchange.com)
Law enforcement officials who believe that notification would jeopardize an investigation should obtain an appropriate court order or other valid legal process that specifically precludes Member notification, such as an order issued pursuant to 18 U.S.C. § 2705 (b). (eff.org)
As you would expect from a law - abiding corporation, Dropbox has made it explicit in its Security Overview that it will release your data to authorities «when it receives valid legal process,» and it will remove their encryption from the data before handing it over. (slaw.ca)