Disclosed herein is a user identity sharing system utilizing a distributed ledger technology security platform. The present invention includes an OFF-CHAIN configured to operate as a regional or national blockchain within a single jurisdiction, in which one or more virtual asset service providers and one or more identity management service providers are participating; and an ON-CHAIN configured to operate as a global blockchain with no borders, in which one or more virtual asset service providers are participating, wherein user identity information of the OFF-CHAIN are shared as de-identified identity information between a virtual asset service provider participating in both the OFF-CHAIN and the ON-CHAIN and another virtual asset service provider participating in the ON-CHAIN, thus preventing forgery of user identity information, and sharing user identity information between virtual asset service providers, other blockchains, distributed ledger technology platforms, and existing IT systems.