Abstract
For the Personal Cloud Storage, security is an important issue. There is latent threat when it comes to the data loss or leakage which may be committed by malicious Cloud Service Provider (CSP) employee. The most basic solution is to encrypt user's data. However, when the encryption key is directly managed by CSP or user's device, then there is latent threat, too. In this paper, we propose the User-Centric Key Management Scheme. This scheme enables user to store mandatory key fragment and enables only user to use the encryption key since optional key fragments are stored in a dispersed manner. Meanwhile, even when mandatory key fragment is lost, this prevents leakage of encryption key.