BLACK LABEL 's security solution, the mutual verification system, allows all coins to be stored on the server of the coin company, leaving only the transaction book records in the personal electronic wallets. Also, replacing COIN company's server entrance and electronic wallet with card and employee pass issued by BLACK LABEL, not ID and PW, and changing log-in with NFC tag makes security of secure password money possible. In order to enter the cryptographic exchange server, the BLACK LABEL's identity authentication server must pass first. At this time, the employees who are allowed to enter the Exchange Server can enter the server by NFC tagging the employee pass with the mutual verification system issued by BLACK LABEL. This is an alternative to the existing ID and PW, and it is not possible to expose it to external hackers because the individual identification code is changed infinitely without pattern, and even if one of them is exposed, it has nothing ...