Insider's guide to securely sharing whistleblower information about corporations, governments, and other powerful institutions

• As an independent news organization, Insider relies on sources to investigate powerful institutions.
• A source may depend on us to protect their identity and may be concerned with sending tips securely.

Tim Cook, Apple's CEO, threatened employees with firing if they share information with journalists. Facebook tried to undermine a whistleblower who divulged damning internal research. Google spies on workers in clandestine ways to try to stop this activity.

When giant corporations, governments, and other powerful institutions are incentivized to cover up problems, the ultimate solutions tend to require a healthy dose of transparency so that democratic societies can see all the facts and decide the best path forward.

As an independent news organization, Insider depends on sources to investigate important institutions. While we look for our sources to speak on the record, sources may sometimes rely on us to protect their identities where they fear negative repercussions for speaking out. We interviewed some of our top journalists to compile a list of some of the options for sharing evidence securely.

If you're an insider concerned about the security of your communications with us, read these tips:

• In general, phone calls are more secure than emails. Signal (see below) is better than traditional phone calls. In-person communication is an even more secure option.
• Consider using a nonwork device that isn't connected to the internet via your organization's networks.
• Consider using a friend's phone if you're concerned your employer is surveilling your devices.
• The best time and place to talk is outside of work - on a lunch break, for instance.
• Use the Signal messaging app. It provides end-to-end encryption, which keeps your communications private. The service is maintained by the nonprofit Signal Foundation. Read more about Signal's security features here. Download it here. We have an Insider tip line that also works on Signal: (646) 768-4744.
• When using Signal, select the "disappearing messages" option. You can choose your messages to be deleted after 30 seconds, five minutes, one hour, or as long as four weeks. Shared documents and photos can also be set to disappear after viewing.
• You can talk over Signal's voice-calling feature, too. This is more secure than a traditional phone line.
• Don't add journalists' contact details to your digital address book. One alternative option is to save those details under a code name in the Signal app.
• Insider also offers SecureDrop for sources who wish to share documents and other information anonymously. The underlying software is maintained by the Freedom of the Press Foundation and is audited by third-party security firms. To access this service, find a nonwork network and get online using a Tor-enabled web browser at the following address.
• If technology is not your strong suit, have a trusted and more adept friend follow these instructions on your behalf. This is particularly applicable to SecureDrop, which requires a higher level of skill than most computer tasks.
• Be wary of which printer you use. Most printers embed a faint watermark that contains the device's serial number and the date and time of printing. Such information can be used to identify the person who printed the document. To avoid this, consider using a shared printer at an internet cafe or library, for example.
• If you have documents or other physical evidence, one of the most secure ways of sharing this is through in-person meetings.
• Physical mail is a relatively simple and secure method of contacting us anonymously. Prepare the letter while wearing gloves, use a self-sealing envelope and store-bought postage, and mail it at a blue USPS mailbox far away from your home and office. If you do not wish to be contacted, do not include a return address. Pay in cash. The addresses of our news bureaus are below:

New York

Insider Inc.
℅ Investigations
1 Liberty Plaza, Floor 8
New York, NY 10006

San Francisco

Insider Inc.
℅ Investigations
535 Mission St., Floor 14
San Francisco, CA 94105

London

Insider Inc.
℅ Investigations
32-38 Scrutton St.
London EC2A 4RQ