By Joseph Menn, Jim Finkle and Dustin Volz SAN FRANCISCO/BOSTON/WASHINGTON (Reuters) – In the summer of 2013, Yahoo Inc launched a project to better secure the passwords of its customers, abandoning the use of a discredited technology for encrypting data known as MD5. In August of that year, hackers got hold of more than a billion Yahoo accounts, stealing the poorly encrypted passwords and other information in the biggest data breach on record. Yahoo only recently uncovered the hack and disclosed it last week.