The present disclosure provides methods and devices for key management. In one example, a method of key management comprises: obtaining, at a user device, a number of users in a group of users and a minimum number of users for restoring a transaction key; randomly generating the transaction key; splitting the transaction key into a plurality of sub-keys, the number of sub-keys being the same as the number of users; and sending the plurality of sub-keys to a management device, each of the plurality of sub-keys being encrypted with a public key of a user corresponding to a sub-key.