Applications of cryptography

With the rising popularity of blockchains, cryptographic techniques are slowly starting to be used for practical purposes besides the obvious. There is still a large number of possible applications for these technologies that haven't been explored yet. Here I mention one application that the government could use.

I'm not publishing the rest of my ideas since I might want to make a startup out of some of them in the future, and also because I have some serious concerns about what might happen if the wrong people implement it.

Digital Signatures and contracts that publish themselves

Signing documents by hand is terribly insecure. It is currently difficult, but not impossible to fake a signature. As machine learning technology continues to improve, it will soon become trivially easy to fake a signature.

Needless to say, if signatures become unreliable and can no longer be trusted, we will be in a lot of trouble, as they form one of the bases for ensuring trust in our society.

Fortunately, there exist algorithms that allow one to sign a document using advanced cryptographic techniques.

These electronic signatures have a number of advantages over traditional ways of signing documents:

• They are virtually impossible to fake. They rely on the same technology that is also used to secure nuclear weapons, so even if someone did figure out how to hack them we would have bigger problems.
• It is impossible to alter a document after it has been signed.
• It becomes possible to publicly sign a document without revealing the actual content of the document (or part of the document, or the signatories). For example, it is possible to keep parts of a contract hidden from the public until conditions are met, and it is possible to let a document be signed by one out of a group of privileged people/entities without giving away which of them signed it. If the missing information is published later, it is possible to confirm that that is indeed the missing information. This allows companies and individuals to sign contracts that are at once secret and public (so they can be held accountable for an action that is not publicized).
• With the support of a trusted entity, such as a major government organisation, it becomes possible to design contracts that are kept secret-yet-public and are automatically revealed, partially-revealed, or destroyed based on complex conditions such as timing, anonymously cast votes of various entities, or automated measurements (e.g. of the stock market or of opinion polls)

It is even possible to enable such cryptographically secure signatures on physical paper documents without too much effort: The simplest solution would be a tool that can scan text and QR codes and that has a configurable stamp for stamping QR codes.