1. A method for creating an electronic document file on a client device to enhance business information security, the method comprising: monitoring creation of an electronic document file on a client device and changes on the electronic document file; receiving a policy file from a server, the policy file including regular expressions, keywords, security policy and document level set-up information, the document level set-up information including importance of words associated with business information, document level policy and user accessibility policy which defines a user's accessibility to a document according to a document level; retrieving a text data from the electronic document file; searching for words associated with business information from the retrieved text data; computing an exposure score, the exposure score indicating the sum of multiplying the number of times for words associated with business information being searched and the importance on words associated with business information; assigning a document level to the electronic document file based on the exposure score; receiving a user's personal information of the client device from the server and inserting a watermark to text of the electronic document file to be displayed on the client device based on the received user's personal information; based on the assigned document level to the electronic document file, performing a security processing according to the security policy, the security processing including one of deletion, isolation, encryption and notification; and creating a protected electronic document file by inserting an accessibility information into a header of the electronic document file.
1. A method for creating an electronic document file on a client device to enhance business information security, the method comprising: monitoring creation of an electronic document file on a client device and changes on the electronic document file; receiving a policy file from a server, the policy file including regular expressions, keywords, security policy and document level set-up information, the document level set-up information including importance of words associated with business information, document level policy and user accessibility policy which defines a user's accessibility to a document according to a document level; retrieving a text data from the electronic document file; searching for words associated with business information from the retrieved text data; computing an exposure score, the exposure score indicating the sum of multiplying the number of times for words associated with business information being searched and the importance on words associated with business information; assigning a document level to the electronic document file based on the exposure score; receiving a user's personal information of the client device from the server and inserting a watermark to text of the electronic document file to be displayed on the client device based on the received user's personal information; based on the assigned document level to the electronic document file, performing a security processing according to the security policy, the security processing including one of deletion, isolation, encryption and notification; and creating a protected electronic document file by inserting an accessibility information into a header of the electronic document file. 3. The method of claim 1 , further comprising downloading the electronic document file from the server to the client device, and wherein the downloading the electronic document file comprises: at the server, verifying a user login of the client device; referring to an organization chart and the user's personal information from a personnel database in the server; referring to the policy file including the security policy and the document level set-up information from a policy database in the server; assigning the document level associated with the user accessibility to the electronic document file based on the document level set-up information and inserting the watermark to the electronic document file based on the user's personal information; encrypting the electronic document file after the assigning the document level and the inserting the watermark; and sending the encrypted electronic document file from the server to the client device.