YOU SAID:
Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending.
INTO JAPANESE
デジタル署名は、ソリューションの一部を提供しますが、信頼できる第三者機関がまだ二重支出を防ぐために必要な場合、主な利点は失われます。
You've done this before, haven't you.