Abstract: A method of transmitting data by which cipher-transmission of digital information data for which forbidden codes including timing identification codes are predetermined can be carried out with enciphered digital information data without containing undesirable forbidden code, in which digital information data contained in word sequence data which contain also time reference code data composed of the timing identification codes are subjected to enciphering process without producing the forbidden code to produce the enciphered digital information data which do not contain any forbidden code and then enciphered word sequence data are constituted with the enciphered digital information data and the time reference code data to be transmitted.

Abstract: Techniques are provided for secure synchronization and sharing of secrets. A first principal acquires an encrypted access key to a secret store of a second principal. The first principal contacts an identity manager and supplies a decrypted version of the access key. One or more secrets of the second principal may be acquired or modified by the first principal while accessing the secret store.

Abstract: A method of transmitting and receiving data in which cipher-transmission of digital information data for which forbidden codes including timing identification codes are predetermined can be carried out with enciphered digital information data without containing undesirable forbidden code. Digital information data contained in word sequence data which also contain time reference code data composed of the timing identification codes are subjected to enciphering process without producing the forbidden code to produce the enciphered digital information data which do not contain any forbidden code. Enciphered word sequence data are constituted with the enciphered digital information data and the time reference code data to be transmitted.

Abstract: Systems and methods are disclosed for enabling encryptor devices to provide real-time messages having offset cryptoperiods according to an offset algorithm within common crypto-sync pulse boundaries. A master clock aligns the encryptor devices to a common crypto-sync pulse. Subsequently, a cryptoperiod offset aligner assigns a different offset value according to an algorithm to each encrypted service. The corresponding encryptor device then begins the cryptoperiod, during which real-time messages are transmitted, at the assigned offset value from the common crypto-sync pulse.

Abstract: A dynamic range of intensity modulation is set to range from a maximum intensity Smax to a minimum intensity Smin. A difference ?(=Smax?Smin) between the maximum intensity Smax and the minimum intensity Smin is divided by the number 2M of multilevel signals. Thus, a distance (an intensity difference) between adjacent signals is [?/2M]. The number 2M of multilevel signals is selected such that the distance [?/2M] between adjacent multilevel signals (between an intensity Si and an intensity Si+1) is sufficiently buried within a range of quantum fluctuations obtained when heterodyne measurements are made or buried within a range of quantum shot noise obtained when a direct detection is made. Bases of a basis group are each positioned for intensity signals so as to have a high intensity and a low intensity between which a distance is set to be a certain value smaller than a middle point intensity [?/2].

Abstract: Enhancements to a video anticopying process that causes an abnormally low amplitude video signal to be recorded on an illegal copy. The enhancements in one version introduce into the overscan portion of the television picture, just prior to the horizontal or vertical sync signals but in active video, a negative going waveform that appears to the television receiver or videotape recorder to be a sync signal, thereby causing an early horizontal or vertical retrace. One version provides (in the right overscan portion of the picture), a checker pattern of alternating gray and black areas which causes the TV set on which the illegal copy is played to horizontally retrace earlier than normal in selected lines with a consequential horizontal shift of the picture information on those lines. This substantially degrades picture viewability. In another version a gray pattern at the bottom overscan portion of the picture causes vertical picture instability.

Abstract: Enhancements to a video anticopying process that causes an abnormally low amplitude video signal to be recorded on an illegal copy. In one version, positive going pulses are added to the video signal. The enhancements in one version introduce into the overscan portion of the television picture, just prior to the horizontal or vertical sync signals but in active video, a negative going waveform that appears to the television receiver or videotape recorder to be a sync signal, thereby causing an early horizontal or vertical retrace. One version provides (in the right overscan portion of the picture), a checker pattern of alternating gray and black areas which causes the TV set on which the illegal copy is played to horizontally retrace earlier than normal in selected lines with a consequential horizontal shift of the picture information on those lines. This substantially degrades picture viewability.

Abstract: Enhancements to a video anticopying process that causes an abnormally low amplitude video signal to be recorded on an illegal copy. The enhancements in one version introduce into the overscan portion of the television picture, just prior to the horizontal or vertical sync signals but in active video, a negative going waveform that appears to the television receiver or videotape recorder to be a sync signal, thereby causing an early horizontal or vertical retrace. One version provides (in the right overscan portion of the picture), a checker pattern of alternating gray and black areas which causes the TV set on which the illegal copy is played to horizontally retrace earlier than normal in selected lines with a consequential horizontal shift of the picture information on those lines. This substantially degrades picture viewability. In another version a gray pattern at the bottom overscan portion of the picture causes vertical picture instability.

Abstract: A sending apparatus generates a first initial vector, a second initial vector, and an encryption key in response to a pseudo random number. Original information is encrypted into cipher information in response to the encryption key and the second initial vector. The cipher information and the first initial vector are transmitted from the sending apparatus to a receiving apparatus. The receiving apparatus generates a first initial vector, a second initial vector, and an encryption key in response to a pseudo random number equal to that in the sending apparatus. The cipher information is decrypted back to the original information in response to the generated encryption key and the generated second initial vector. The receiving apparatus compares the received first initial vector and the generated first initial vector to check whether or not encryption/decryption-related synchronization between the sending apparatus and the receiving apparatus is normally maintained.

Abstract: Enhancements to a video anticopying process that causes an abnormally low amplitude video signal to be recorded on a illegal copy. The enhancement in one version include a negative going waveform that appears to the television receiver or videotape recorder to be a sync signal, thereby causing an early horizontal or vertical retrace. In another version, selected horizontal sync pulses are narrowed, causing irregular vertical retraces. In another version, post-pseudo sync pulses that have a minimum level above the minimum level of sync pulses are added to enhance anti-copy effectiveness. The post pseudo-sync pulses may be amplitude modulated.

Abstract: A method and system are provided for protecting an analog video signal sent from a video signal source to a video display enabled to receive a protected video signal. The method includes sending a string of bit values in an encrypted format from the video display to the video signal source. The string of bit values is received in the video signal source and decrypted. The string of bit values is then divided into multi-bit segments in both the video display and the video signal source. A common multi-bit segment in the string of bit values is selected for both the video display and video signal source. A plurality of analog video channels is then sent in a switched order from the video signal source to the video display based on the common multi-bit segment. The plurality of analog video channels is finally decoded in the video display using the common multi-bit segment to decode the switched order.

Abstract: A modified Colorstripe™ copy protection process utilizes a basic anti-copy protection (ACP) signal that causes attenuation of a video signal, wherein, in one embodiment, the process modifies (lowers) the level of a front porch portion and adds an incorrect color signal (color burst) in the region of the sync tip. When an illegal copy is made, a pre-blanked end of line portion causes a TV set to trigger the color burst sample pulse ahead of time and cause the incorrect color signal in the sync tip region to be sampled. Thus, since the sync tip region has incorrect color phase or frequency, the resulting illegal copy will have enhanced color distortions. In other embodiments, other portions of the horizontal blanking interval are lowered in level and incorrect color bursts are added to a portion or portions of the back porch and/or a portion of the front porch.

Abstract: A method and apparatus for defeating copy protection signals in a video signal, and also for providing copy protection signals for a video signal, is disclosed. The defeat technique generally utilizes a particular pulse position shifting, modulation, etc., of AGC, normal sync and/or pseudo sync pulses to increase the separation between the pulses. Various embodiments are disclosed including selective shifting of the relative positions of either the sync/pseudo sync or AGC pulses, trimming portions of the sync/pseudo sync and/or the AGC pulses and narrowing of either the sync/pseudo sync and/or the AGC pulses, all to provide the selective position separation between the sync/pseudo sync and AGC pulses.

Abstract: Video signals are scrambled by position modulating or switching between two types of modified horizontal sync pulses. These modified horizontal pulses are modulated or switched at a rate that causes a non-interlaced tearing pattern when viewed by an unauthorized viewer, whereby greater concealment is achieved by the invention when compared to the prior art. The modified scrambling process also is adapted to achieve lower tuner AGC artifacts. With added fake vertical sync signals and strategic use of double or multiple horizontal sync pulses per TV line, modern TV sets using count down circuits are also affected vertically to enhance the concealment effects.

Abstract: In a known copy protection process for preventing recording of video signals, pseudo sync and AGC pulses are present on predetermined lines within the blanking intervals of the video signal so that any subsequent video tape recording of the video signal shows a picture of very low entertainment quality. This copy protection process is defeated first by determining the location of the video lines containing the copy protection using the color burst signal or chroma in the horizontal blanking interval to determine on-line detection. Then some or all of the lines including copy protection signals are modified so as to render the overall video signal recordable. The modification is accomplished in a number of ways, including gain shifting portions of the video signal, level shifting portions of the video signal, bandwidth limiting certain portions of the video signal or replacing certain portions of the video signal with other video elements.

Abstract: Copy protection for composite video signals is well known. Copy protection, while it does not prohibit making a copy per se, does render any copy (recording) of the video signal relatively unviewable so that the viewer's enjoyment of the picture is severely reduced or none. Methods for reducing the effects and/or defeating copy protection are also known. The present method and apparatus reduce effects of added copy protection pulses by further adding other pulses that counteract the gain reduction caused by the copy protection pulses of the type known as automatic gain control (AGC) or pseudo-sync pulses.

Abstract: In a known copy protection process for preventing recording of video signals, pseudo sync and AGC pulses are present on predetermined lines within the blanking intervals of the video signal so that any subsequent video tape recording of the video signal shows a picture of very low entertainment quality. This copy protection process is defeated first by determining the location of the video lines containing the copy protection using the color burst signal or chroma in the horizontal blanking interval to determine on-line detection. Then some or all of the lines including copy protection signals are modified so as to render the overall video signal recordable. The modification is accomplished in a number of ways, including gain shifting portions of the video signal, level shifting portions of the video signal, bandwidth limiting certain portions of the video signal or replacing certain portions of the video signal with other video elements.

Abstract: A method for defeating illegal receivers sensitive to the edges of synchronization signals in a scrambled video signal is provided. The scrambled video signal includes synchronization signals having levels which prevent a standard receiver from detecting the synchronization signals by using the levels of the synchronization signals. The synchronization signals also have one or more pulses with level transitions above or below a signal detection threshold level of the standard television receiver which prevent the illegal receivers from detecting the synchronization signals by using the edges of the synchronization signals.