Provided are a system and method of encrypting a folder in a device. The device for controlling access to the folder includes a communication part configured to transmit, to a server, an encryption key generation request with respect to the folder, and receive, from the server, an encryption key associated with the folder that is generated in response to the encryption key generation request, wherein the encryption key generation request includes an identification of the folder and authentication data of a user who accesses the folder is an authorized user; and a controller configured to authenticate the user by using the encryption key.