摘要:
Techniques for secure distribution of digital representations that combine encryption and watermarking. When a user at a client desires to download a digital representation, the user makes a request to a server for the digital representation, which encrypts the digital representation using a first key and downloads the encrypted digital representation to the user. Before the user performs any operation on the decrypted digital representation, a secret fingerprint watermark identifying the user is added to the digital representation. The fingerprint watermark is added either at the server or at the client and a copy of the fingerprinted digital representation is kept at the server. If the user makes an impermissible use of the digital representation, the secret fingerprint watermark can be used to identify the user. The request made by the user indicates the type of use that the user wished to make of the digital representation. If the use involves storage of the digital representation at the client, the server provides a second key that the client employs to encrypt the digital representation. If the user has permission to do so, the user may modify the digital representation and return the modified digital representation to the server for further distribution. In this case, the second key is used to encrypt the digital representation when it is sent to the server. The second key also serves as the user identification in the fingerprint watermark. If the user loses the second key, it can be recovered from the copy of the fingerprinted digital representation kept at the server. The first and second keys and any decrypted copy of the digital representation are kept in secure storage in the client.
摘要:
Techniques for protecting the security of digital representations, and of analog forms made from them. The techniques include authentication techniques that can authenticate both a digital representation and an analog form produced from the digital representation, an active watermark that contains program code that may be executed when the watermark is read, and a watermark agent that reads watermarks and sends messages with information concerning the digital representations that contain the watermarks. The authentication techniques use semantic information to produce authentication information. Both the semantic information and the authentication information survive when an analog form is produced from the digital representation. In one embodiment, the semantic information is alphanumeric characters and the authentication information is either contained in a watermark embedded in the digital representation or expressed as a bar code. With the active watermark, the watermark includes program code. When a watermark reader reads the watermark, it may cause the program code to be executed. One application of active watermarks is making documents that send messages when they are operated on. A watermark agent may be either a permanent resident of a node in a network or of a device such as a copier or it may move from one network node to another. In the device or node, the watermark agent executes code which examines digital representations residing in the node or device for watermarked digital representations that are of interest to the watermark agent. The watermark agent then sends messages which report the results of its examination of the digital representations. If the watermarks are active, the agent and the active watermark may cooperate an the agent may cause some or all of the code than an active watermark contains to be executed.
摘要:
A system and method are described for inserting a watermark in encoded content, including receiving encoded content, receiving at least one pre-processed watermark unit and replacing directly a number of bits starting at a position in the encoded content with an alternative value, wherein the alternative value has embedded therein watermark signals, wherein the alternative value is selected from among a plurality of alternative values specified in the at least one said watermark unit. An apparatus and method for generating watermark units are also described including selecting a position where a value in encoded content is to be replaced by an alternative value and calculating a plurality of alternative values for each selected position. Further a system and method for replacing a watermark in encoded content are also described including receiving encoded content, receiving at least one pre-processed watermark unit and replacing a number of bits starting at a position in the encoded content with a value, wherein the value is specified in the at least one watermark unit.
摘要:
A system and method are described for inserting a watermark in encoded content, including receiving encoded content, receiving at least one pre-processed watermark unit, and replacing directly a number of bits starting at a position in the encoded content with an alternative value, wherein the alternative value has embedded therein watermark signals, wherein the alternative value is selected from among a plurality of alternative values specified in the at least one said watermark unit. An apparatus and method for generating watermark units are also described including selecting a position where a value in encoded content is to be replaced by an alternative value and calculating the alternative value a plurality of alternative values for each selected position. Further a system and method for replacing a watermark in encoded content are also described including receiving encoded content, receiving at least one pre-processed watermark unit and replacing a number of bits starting at a position in the encoded content with a value, wherein the value is specified in the at least one watermark unit.
摘要:
Disclosed is a method of marking binary-coded data sets, especially image data or audio signals, by applying at least one information unit to a data set. The invention is characterized by the generation of a discrete position sequence for the application of information units to the data set to be marked, taking into account data-specific characteristics and using a key; and by the fact that the information unit to be applied is written and read at the positions established in the position sequence in the data set.
摘要:
An electric machine has a stator and a rotor. The stator has a housing and at least one pair of magnetic poles. Each magnetic pole has a primary magnet and two auxiliary magnets disposed on respective sides of the primary magnet. All of the magnets are disposed on an inner surface of the housing. All the magnets of a magnetic pole have the same polarity.
摘要:
The invention provides methods and compositions for the modulation of proanthocynidin (“PA;” condensed tannin) production in plants. The methods of the invention allow creation of plants having novel phenotypes, such as alterations in levels of PA or in the types of tissues in which PAs are produced. Altered expression of PA in plants may be achieved, for instance without significantly affecting anthocyanin content or overall secondary metabolite profiles. Alternatively, expression of PA in plants may be achieved while also affecting anthocyanin content.
摘要:
Agomelatine crystal, which is a drug for treating depression, and pharmaceutical compositions thereof are provided. The X-ray powder diffraction spectra of such agomelatine crystal, which is irradiated by Cu-Kα and showed by 2θ(degree), has characteristic diffraction peaks at 12.84, 13.84, 16.14, 18.56, 19.12, 20.86, 21.20, 23.84; its IR absorption pattern has characteristic absorption peaks at about 3234, 3060, 2940, 1638, 1511, 1436, 1249, 1215, 1184, 1032, 908, 828, 755, 588 cm-1, and its DSC endothermic transition temperature is 97.6° C. The use of the agomelatine crystal as an active ingredient in preparing a medicament for the treatment of depression is also provided.
摘要:
A brushless motor has a stator and a rotor. The stator has a stator core with a plurality of inwardly extending salient poles and windings wound about the salient poles. The rotor has a shaft, a rotor core fixed onto the shaft, and magnets inserted in the rotor core for forming magnetic poles of the rotor. Each of the salient poles has a pole shoe with a pole face that extends along a circumferential direction confronting the rotor core and being spaced from the rotor core by an air gap. In a radial cross section of the motor, each of the magnetic poles of the rotor has an effective dimension (W) which is about 0.85 times to 1.2 times of the chord length (L) of each pole face.
摘要:
A method of transmitting data between a plurality of base stations and a plurality of mobile stations is provided. The method includes ranking data links between the plurality of base stations and the plurality of mobile stations according to a quality criterion, and selecting a subset of data links for transmitting the data between the plurality of base stations and the plurality of mobile stations such that a predetermined requirement is satisfied. Selecting the subset of data links may include iteratively assigning a predetermined value to power of the data link having the lowest ranking and determining if the predetermined requirement is satisfied, until the predetermined requirement is no longer satisfied. The remaining data links may then be selected for transmitting the data between the plurality of base stations and the plurality of mobile stations.