San Francisco-based Twitter has acquired password management software developer Mitro, Mitro said Thursday, and has open sourced Mitro's tools. Financial terms of the buy were not disclosed. Mitro said that its team is joining Twitter to work on geo-related projects in New York. Twitter is not buying Mitro's software, which have been open sourced under the GPL license, with help from the Electronic Frontier Foundation (EFF). Mitro was venture backed by Google Ventures and angels.