As Ben Franklin said, "Three can keep a secret, if two of them are dead." There's no technical solution for that. End-to-end encryption will help if one person

As Ben Franklin said, "Three can keep a secret, if two of them are dead." There's no technical solution for that. End-to-end encryption will help if one person sends information to one competent, trustworthy journalist. It won't help much if large groups of people try using it to conspire to overthrow a government: someone will talk, someone will be an undercover double agent.