Microsoft filed a patent for "quantum computational systems" back in 2009 and received confirmation by the USPTO yesterday.
What makes this patent interesting is not just the fact that Microsoft has begun covering its bases in quantum computing, which gives this field much more credibility, but its general nature to improve on "prior art" in topological quantum computing. Without a deep dive into quantum computing itself, much of the content covered by patent is confusing enough to make your head spin, but it is obvious that Microsoft is targeting quantum computing functionality in wide range of applications.
The Microsoft patent refers to specific quantum computing devices, including quantum computers, quantum cryptography systems, quantum information processing systems, quantum storage media, and special purpose quantum simulators, all of which are covered in this patent by themselves and in combination with traditional computing systems. Microsoft spends quite a bit of time on cryptography systems and states that "cryptography also would be revolutionized" if computers could "exploit quantum mechanical superpositions".
In a cryptography application, Microsoft explains that "respective braids that correspond to the plain text and the encryption key may be defined. The key braid may be applied to the plain-text braid to generate an encrypted-text braid. To decrypt the encrypted text, the key braid may be applied to the encrypted text braid to reestablish the plain-text braid." It is generally believed that quantum computing systems could deliver cryptography applications that are far more secure than today's solutions