An unprecedented milestone result in cryptography was achieved by researchers at University of Birmingham.
They have build a TIME release encryption system based on the bitcoin network. In their protocol it is possible to release a certain document in the future in such a way that it CANNOT be read earlier.
The new protocol relies on the fact the the bitcoin network has ENORMOUS computing power which no one can match (not even the NSA). The secret simply cannot be released earlier.
The timing of release of the secret can be set quite precisely and the release can be programmed in advance.