Signal
In July in Detroit, police officers apprehended two young men, one of whom was carrying a small package synthetic drugs. He turned out to be a drug courier. He turned on the phone, launched Signal messenger, entered the password and showed the cops his conversation with the supplier nicknamed Best_Work. The guy ended up being sentenced with 8 years of prison, while Best_Work remained unidentified, as follows from the protocol.
According to the judge's words, "Signal is a communicator that does not allow for identification of the user's personality". Its developer is an American non-commercial company Open Whisper Systems. Its technological stack is also used by WhatsApp and Facebook Messenger. The account is linked to the mobile phone number, but the interface looks oldy and ascetic after Telegram.
Wickr Me
In the summer of 2017, a court proceeding in Illinois was attended by a cybersecurity officer from the CIA who pledged that Wickr messenger is designed and perfectly fit for anonymous communication, since it doesn't provide the data on both time and location of the sender. This short lecture on modern online privacy technologies was needed in the frameworks of a criminal action against another drug courier who received instructions from an anonymous user nicknamed kakaubul23. In order for the messages not to disappear, the police officers involved photographed all the communication history.
Wickr, just like Signal, was developed by American developers, but, unlike the Snowden-favorite messenger, Wickr allows to create accounts without linking them to the phone number.
CoverMe
In August 2015, a Thai citizen saw the ad on the recruitment of couriers and long-haul shippers for sports foods in South-East Asia. In a week, he was standing in the line on Bangkok railway terminal where an unknown man handed to him a ticket to Hanoi and a phone with pre-installed CoverMe messenger. In Vietnam, the protagonist got to realize that "sports foods" meant drugs. Later, the anonymous users directed him to Ho Chi Min where he was finally arrested. The police didn't manage to identify the other actors " due to the fact that CoverMe does not contain the direct links that would allow for identification of the actors".
CoverMe is a product by the same-named company based out of San Jose, California. Apart from encrypted messages, the app offers a paid option of getting a virtual phone number with American or Canadian prefixes. A cool specialty of the app is that upon shaking the phone, neutral photographs pop up on the screen, while re-entry to the app will require a special password.
There're also Vipole and ChatSecure, check them out
Indeed, but the concept is the same
Telegram suffices, there's no evidence, and has never been, that it had been hacked.
Tutorial for drug dealers? :]