What is the current mature practice of identity identification and non-repudiation in the paperless office of an enterprise?

Please give some suggestions. It is best to have specific techniques and examples.

Mar.03,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b366bb-2c028.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b366bb-2c028.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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