Abstract: A method for protecting a PDF document page-by-page, including the following steps: traversing all the page content stream objects in the PDF document, if any one page content stream object is reused by a plurality of pages, copying the content stream object according to the number of times of same being used; establishing an index table from a PDF page number to the page content stream object in a memory; searching for, according to the page number of the protected page, the corresponding page content stream object from the index table; encrypting stream data of the acquired page content object using the secret key B; adding an encryption identification C to an object dictionary of the encrypted page stream object; respectively creating a cover layer with the same length and width as various protected pages; and placing various cover layers on the top of the protected page.

Abstract: An electronic and paper combined data submission, printing, and retrieval method includes: completing an application in a client terminal, sending the user-entered data in the client terminal to a remote storage server; printing the completed application together with a barcode containing a unique identification code; retrieving the electronic data stored in the remote storage server by scanning said identification code. A system includes: a data encryption module; a data transmission module; an identification code module; a print module; a scan module; an analysis module; a data retrieve module; and a data decryption module.

Abstract: A method for erasing electronic handwriting on a clipboard includes: the coordinates of each handwriting point of the electronic handwriting are made to correspond to writing pressure on the clipboard and are stored, and the color depth of each handwriting point is made to be proportional to the writing pressure at the handwriting point; the coordinates of each erase point, on the clipboard, contacted by the eraser are made to correspond to erasing pressure applied to the clipboard by the eraser via the erase points; determining whether the coordinates of the erase points are the same as one of the coordinates in the handwriting points, and if so, then determining the color depth at that erase point according to a first non-negative rule; otherwise, the color depth at the erase point is the background color depth of the clipboard.

Abstract: The present invention discloses a method for identifying PDF document. wherein, it comprises the following steps: S1: analyzing the path objects in the PDF document, and identifying the forms in PDF document; S2: analyzing the text objects outside the form regions in the PDF document, and recognizing the text contents in the PDF document; S3: writing the identified results into a temporary file, or writing them into the PDF document as an attachment. The method for identifying PDF document provided by the present invention could identify the tables, the paragraphs, titles, the tabulations and so on in the PDF document, thereby, the PDF document can be edited with the paragraph as a unit, and be tagged conveniently to confirm the reading order, so as to facilitate the reading of people with visual impairment; in the same time, it also can derive document in other forms according to the identified results, which thereby greatly facilitates users to read and edit the PDF document.

Abstract: A method for displaying handwriting in a PDF file includes: determining the embedding location of handwriting annotated in a PDF file; correspondingly recording coordinates and pressure data of each stroke point, on the screen, contacted by a stylus, and recording the sequence in which the stylus makes contact with the stroke points; establishing a correlation between pressure data and color, thus establishing a correlation between coordinates of the stroke points and color; displaying the stroke points in their colors, and connecting all of the stroke points according to the sequence in which the stylus makes contact with the stroke points, forming handwriting data, wherein color of the connecting line between consecutive stroke points is displayed according to a function; forming a graphic according to the handwriting data, and combining the handwriting data with the graphic to form an annotation; and embedding the handwriting annotation in the embedding.

Abstract: The present invention relates to a method for improving clarity of a PDF file converted from a paper file.

Abstract: The present invention discloses a kind of management method for digital rights, wherein, it comprises the following steps: Step S1: the original electronic file is encrypted on the server-side, and in the meantime, the flow code, the file unique identifier, the authorization locations and verification information is injected; Step S2: obtaining flow codes, file identifier, authorization locations and verification information from the encrypted file, and then conducting integrality verification thereon; step S3: After it is verified that there is no error, the related information is sent to the authorization server; S4: after receiving the injection information about the encrypted file, the authorization server conducting integrality verification firstly, then judging the type of encryption file according to the flow code, and generating an authorization file and sending the same according to the type; Step S5: a decryption tool obtaining the authorization file to conducting integrality verification on the aut

Abstract: The present invention discloses a kind of management method for digital rights, wherein, it comprises the following steps: Step S1: the original electronic file is encrypted on the server-side, and in the meantime, the flow code, the file unique identifier, the authorization locations and verification information is injected; Step S2: obtaining flow codes, file identifier, authorization locations and verification information from the encrypted file, and then conducting integrality verification thereon; step S3: After it is verified that there is no error, the related information is sent to the authorization server; S4: after receiving the injection information about the encrypted file, the authorization server conducting integrality verification firstly, then judging the type of encryption file according to the flow code, and generating an authorization file and sending the same according to the type; Step S5: a decryption tool obtaining the authorization file to conducting integrality verification on the aut