TY  - JOUR
T1  - Data Block based User Authentication for Outsourced Data
AU  - Hahn, Changhee 
AU  - Kown, Hyunsoo 
AU  - Kim, Daeyeong 
AU  - Hur, Junbeom 
JO  - Journal of KIISE, JOK
PY  - 2015
DA  - 2015/1/14
DO  - 
KW  - data outsourcing
KW  - multi-factor authentication
KW  - hash tree
KW  - usability
AB  - Recently, there has been an explosive increase in the volume of multimedia data that is available as a result of the development of multimedia technologies. More and more data is becoming available on a variety of web sites, and it has become increasingly cost prohibitive to have a single data server store and process multimedia files locally. Therefore, many service providers have been likely to outsource data to cloud storage to reduce costs. Such behavior raises one serious concern: how can data users be authenticated in a secure and efficient way? The most widely used password-based authentication methods suffer from numerous disadvantages in terms of security. Multi-factor authentication protocols based on a variety of communication channels, such as SMS, biometric, or hardware tokens, may improve security but inevitably reduce usability. To this end, we present a data block-based authentication scheme that is secure and guarantees usability in such a manner where users do nothing more than enter a password. In addition, the proposed scheme can be effectively used to revoke user rights. To the best of our knowledge, our scheme is the first data block-based authentication scheme for outsourced data that is proven to be secure without degradation in usability. An experiment was conducted using the Amazon EC2 cloud service, and the results show that the proposed scheme guarantees a nearly constant time for user authentication.