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What is the most secure way for two people to communicate digitally when one person is in the U.S. and the other is in China (likely being monitored)?

Updated: Here's some additional info:

  • The data are traveling both ways.
  • The amounts of data are small: less than 10MB usually.
  • GPG may satisfy the requirements. I posted the question here because my understanding of infosec is not sophisticated enough for me to make that judgement myself.

Revised scenario:

Two parties wish to share information digitally, back-and-forth. One party is in the U.S., the other in China. The two parties do not want any other parties to be able to decipher the information at any point in the stream. The data transfers have a maximum size of 10MB. The budget is small – $10/month.

If PGP or GPG will meet these needs – that's perfect. I'm asking in case there is a vulnerability in this scenario that I'm not aware of or considering appropriately.

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    While a great idea for a question, as it reads, there's a trivial answer: "meet in person and give them a sealed USB stick". Could you please edit your question to include details like: which direction(s) is the data travelling? What kind of data you need to exchange? What technologies / budget do you have available? (suggestions for a $0 budget will be very different from a $100k budget) – Mike Ounsworth Aug 7 '15 at 15:24
  • Also the expected volume of data would be great – user69377 Aug 7 '15 at 15:33
  • Plain old email with PGP encryption would probably suffice in most cases, unless you want to hide the fact that you are using encryption. – tlng05 Aug 7 '15 at 17:37
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With the Great Firewall of China, the country has a tight grip on its communication infrastructure, especially on the IP and TCP layer, however there are still some options left. It all depends on the volume or reliability though.

Be careful! By using VPN or TOR you will become subject of investigation, especially if you are building connections to the USA

VPN:

China Unicom, one of the biggest telecoms providers in the country, is now blocking connections where a VPN is detected, according to one company with a number of users in China.

In early 2015, China cracked down on VPNs, software that allows internet users to access Twitter, Facebook, Gmail and others websites blocked in the country, according to state media and service providers. Many users reported VPN service disruptions. However, some VPN providers still work in China.

TOR:

Tor is most of the country, however that many IP addresses inside the China Education and Research Network (CERNET) are able to connect to at least to the Tor relay. Apart from the CERNET netblock, the filtering seems to be quite effective despite occasional country-wide downtimes.

SSH tunneling

By establishing an SSH tunnel, a user can forward all their traffic over an encrypted channel, so both outgoing requests for blocked sites and the response from those sites are hidden from the censors, for whom it appears as unreadable SSH traffic.

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