How to be sure texts and calls are encrypted after FBI warning about Chinese hackers

Government officials warned on Tuesday that a major Chinese hacking campaign against US telecommunications companies has not been completely eradicated and that the best way to hide communications from Beijing's spies is to use encryption.

Encryption is a technology that encrypts a message and requires a “key” to be able to see or hear it.

Different app makers and platforms have used the technology in various ways for more than a decade so that governments and hackers using those resources as they pass through the telecommunications infrastructure will only see madness. While using the technology has long drawn complaints from law enforcement — including the FBI — it's also a way for people to communicate privately.

Telecommunications companies often keep temporary records of calls and SMS – which phone number called or sent a text message to which one, and when – and they also store briefly the content of SMS texts. The sound, however, is usually not recorded. That means it's easy for hackers like those in the Chinese campaign, which Microsoft has dubbed Salt Storm, to get large amounts of data from phone records and other stored messages, but they must be targeted at listening to specific calls as they happen. .

For everyday consumers, the easiest way to send encrypted messages or make encrypted calls is to use messaging apps like Signal or WhatsApp that have implemented end-to-end encryption between other Signal and WhatsApp users. With end-to-end encryption, every user of an encrypted chat app carries a unique code to delete a message sent to that account. Importantly, the owner of the business and the user of the application do not have access to that key, so they will not be able to delete the encrypted message even if a court demands it or it is hacked.

Signal and WhatsApp automatically protect all their messages with Signal's encryption, which cryptographers find among the best commercially available.

Both apps allow users to make encrypted phone calls with other users over the Internet.

But even without apps like Signal and WhatsApp, most Americans tend to write with end-to-end encryption turned on, even if they can't.

When iMessage users write to other iMessage users or Google Messages users write to other Google Messages users, those conversations are automatically encrypted using the Signal protocol.

But when Google and iMessage users send text to users using different texting applications, such as when an iMessage user writes to a Google Messages user, the messages are encrypted only through Rich Communication Services, which in the US are all decrypted by Google. While that means they're hidden from social media companies, they're not encrypted in the end, and they can't be seen under court orders to Google or potential hackers.

For phone calls, Google and Apple offer encryption when calls are made through their online calling apps – Google Fi and FaceTime.

While the controversial app Telegram offers what it says is an option to send messages to users with end-to-end encryption, some leading cryptographers are wary of supporting it, noting that some of its code is not open to public inspection and that it does not automatically encrypt conversations.

The FBI began investigating the Salt Storm in late spring or early summer. The US believes that Chinese intelligence broke into AT&T, Verizon and Lumen Technologies and gained access to important information, including records of many people's calls and text messages, mainly in the Washington, DC area. In some cases, members of both the Trump and Harris campaigns, as well as the office of Senate Majority Leader Chuck Schumer D.N.Y., were able to wiretap the calls.

China has denied the accusations, as it always does when a Western company or government accuses it of using its vast cyberespionage capabilities. A spokesperson for China's embassy in Washington said in an emailed statement that “China strongly opposes the US smear attack against China without any factual basis.”

This article was originally published on NBCNews.com