Abstract: A document decryption/encryption method is incorporated with local server software for dynamically decrypting a document when the document is read. The method packages the document by encrypting the document with encryption software, attaches a local server software with the encrypted document so as to generate a corresponding package file having the local server program and the encrypted document together, and executes the package file by a local host. A local server program is provided by executing the local server software and loading the server program into the system memory of the local host, and the document is dynamically decrypted by the local server program when the document is read by a reading device associated with the local server program so as to open the document.