The world’s fourth-largest telecoms provider, Japan’s Nippon Telegraph and Telephone (NTT), has filed a patent for using blockchain tech for contract agreement. The patent was released by U.S. Trademark and Patent Office. The patent suggests a “simple, possible way to solve this problem is to, for example, include the electronic signatures of all the involved parties in one transaction.” NTT’s patent proposal is one of several to have already surfaced from major corporations this week: Mastercard and Bank of America have also released documentation for blockchain-based inventions.