What are time stamps?
クラウドサイン運営事務局 avatar
Written by クラウドサイン運営事務局
Updated over a week ago

Time stamps are digital verifications of time issued by a trusted authority.

With CloudSign, all documents are applied with time stamps. For the documents it has been used with, the technology certifies “when” a contract was concluded for “what.”

* For Free Plan users and those on the Standard Plan with no long-term signature function included, documents you sent that were concluded before September 6, 2020 are not applied with a time stamp.

Role of time stamps

  • The digital data existed at the exact time of the time stamp (proof of existence of data)

  • The digital data has not been tampered with after the exact time of the time stamp (non-tamper evidence)

CloudSign uses the time stamp services of AMANO (AMANO Corporation) acting as a “Time Stamping Authority (TSA)” as stipulated by the National Tax Agency of Japan under the Law(or Act) on Book and Record Keeping through Electronic Methods.

Applying this extends the term of validity of electronic signatures to ten years.


This site includes CloudSign as a company using trusted time stamps.


Please also see here for more details on electronic signatures.

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