Tham khảo tài liệu 'hacker professional ebook part 185', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | authentication then signed digital documents can be exchanged between users in different nations using different software on different platforms this interoperability is necessary for a true digital economy to develop. The lack of secure authentication has been a major obstacle in achieving the promise that computers would replace paper paper is still necessary almost everywhere for contracts checks official letters legal documents and identification. With this core of necessary paper transaction it has not been feasible to evolve completely into a society based on electronic transactions. Digital signatures are the exact tool necessary to convert the most essential paper-based documents to digital electronic media. Digital signatures makes it possible for example to have leases wills passports college transcripts checks and voter registration forms that exist only in electronic form any paper version would just be a copy of the electronic original. All of this is enabled by an accepted standard for digital signatures. Is RSA patented RSA is patented under . Patent 4 405 829 issued 9 20 83 and held by Public Key Partners PKP of Sunnyvale California the patent expires 17 years after issue in 2000. RSA is usually licensed together with other public-key cryptography patents see Question . PKP has a standard royalty-based licensing policy which can be modified for special circumstances. If a software vendor having licensed the public-key patents incorporates RSA into a commercial product then anyone who purchases the end product has the legal right to use RSA within the context of that software. The . government can use RSA without a license because it was invented at MIT with partial government funding. RSA is not patented outside North America. In North America a license is needed to make use or sell RSA. However PKP usually allows free non-commercial use of RSA with written permission for personal academic or intellectual reasons. Furthermore RSA .
