Patent ID: 11930103
Assignee: VECHAIN GLOBAL TECHNOLOGY, S.AR.L
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC H

Claim 2:
3. A method of key management with a group of users, the group of users including an organizing primary user for creating the group of users and a primary user for splitting a transaction key, the method comprising:
obtaining, at a management device, group information about the group of users from a user device of the organizing primary user, the group information indicating at least the number of users in the group of users and a first predetermined value, the first predetermined value indicating the minimum number of users for restoring a transaction key, the group of users being used to manage the transaction key;
sending a message to a user device of the primary user for splitting the transaction key, wherein the message is related to a first one of the users in the group of users other than the primary user for splitting the transaction key, wherein the message indicates at least a public key of the first one of the users;
obtaining a plurality of sub-keys from the primary user for splitting the transaction key, the number of sub-keys being the same as the number of users in the group of users, wherein the plurality of sub-keys were generated by the primary user for splitting the transaction key by randomly generating the transaction key and then splitting the transaction key, the plurality of sub-keys being encrypted with public keys of the respective users;
caching the plurality of sub-keys for sending to the respective users;
specifying or randomly determining, in the group of users, at least one of:
at least one of the organizing primary user and the primary user for splitting the transaction key; and
a restoring user for restoring the transaction key;
in response to receiving a request for a present transaction, sending, to users of the group of users, transaction information for determining whether the present transaction is approved, the transaction information indicating at least transaction content of the present transaction and an identification of the restoring user;
obtaining a sub-key of each confirming user in the group of users, the confirming user approving the present transaction, the sub-keys of the confirming users being signed with a public key of the restoring user; and
in response to determining that a condition for the present transaction is satisfied, sending, to the restoring user, a restoration message for restoring the transaction key.