For the landlocked, may I recommend the Dead Drop Protocol? Leave the message in a place that everyone knows about, but only the intended recipients knows a message is there to be read. Like the Message in a Bottle, it supports all encryption methods and is disconnected from the Internet.
There are a couple drawbacks, though. For one, unless you are watching the drop point, you have no way of knowing whether your message made it to the intended recipient or if it was intercepted. Vice versa, if you are the intended recipient of a dropped message, the only guarantee you have that the message is authentic is if the message uses a self-authenticating encryption method. Also, there is a potential that any drop point you use may be under surveillance, so make sure to not use the same drop point too often.
For the landlocked, may I recommend the Dead Drop Protocol? Leave the message in a place that everyone knows about, but only the intended recipients knows a message is there to be read. Like the Message in a Bottle, it supports all encryption methods and is disconnected from the Internet.
There are a couple drawbacks, though. For one, unless you are watching the drop point, you have no way of knowing whether your message made it to the intended recipient or if it was intercepted. Vice versa, if you are the intended recipient of a dropped message, the only guarantee you have that the message is authentic is if the message uses a self-authenticating encryption method. Also, there is a potential that any drop point you use may be under surveillance, so make sure to not use the same drop point too often.