摘要:
In a communication system for performing communication while switching between full-duplex communication and half-duplex communication, a slave 200, which receives command packet signals requesting to write or read data from the master 100, houses information, in a response packet signal, that specifies half-duplex communication in response to one of the received packet signals, and transmits the response packet signal to the master, when the number of the received command packet signals has reached the maximum number of the command packet signals storable in a command signal queue 252.
摘要:
When advance prediction is conducted for overflows and underflows, which are both types of buffer errors, and the occurrence of a buffer error is predicted, frames that a viewer will be unlikely to notice even if playback is omitted or conducted for a different duration from a predetermined standard duration are omitted or played for a different playback duration.
摘要:
A server apparatus encrypts content, based on a distribution key, and transmits the encrypted content to a PC via a network. The PC, to which a memory card is connected, outputs the received encrypted content to the memory card. The memory card decrypts the encrypted content using the distribution key, converts the data format of the decrypted content, encrypts the content using a medium unique key that is unique to the memory card, and records the resulting re-encrypted content internally. A playback apparatus decrypts the re-encrypted content using the medium unique key, and plays back the decrypted content.
摘要:
There are disclosed an extended key generator, encryption/decryption unit, and storage medium, in which as each of key transform functions, a transform process is done by an S box (substitution table) on the basis of a first key obtained from the inputted key, and an adder computes a corresponding one of extended keys on the basis of a value obtained by shifting the transformed result of the S box to the left, and a second key obtained from the inputted key.
摘要:
A cross-bus switch apparatus which establishes simultaneously two or more pairs of connections between (i) a source bus arbitrarily selected from a plurality of source buses connected to one or more source apparatuses and (ii) a destination bus arbitrarily selected from a plurality of destination buses connected to one or more destination apparatuses. The cross-bus switch apparatus includes: a plurality of cross-bus switch units. The plurality of source buses are grouped into a plurality of source bus groups which are each connected to one of the plurality of cross-bus switch units. The plurality of destination buses are grouped into a plurality of destination bus groups which are each connected to one of the plurality of cross-bus switch units. Each cross-bus switch unit is connected to either (i) a source bus group or a destination bus group, or (ii) a source bus group and a destination bus group.
摘要:
A communication interface of the present invention includes a clock signal line, a first signal line, a second signal line and one or more data signal lines as communication signal lines between a master system and a slave system.
摘要:
A DMA control device and a data transfer method, which make it possible to use a DMA channel independent of an operation mode of a processor and realize the protection of DMA control parameters during DMA operation (during a data transfer), while reducing the number of shift of an operating mode of the processor as small as possible, are provided. In requesting a DMA start by locking an access to a ch-0 DMA control register 114 in a secure mode, a CPU 101 instructs an unlock set register 118 to release an access lock when the transfer is completed. Then, when a parameter controlling circuit 119 receives a notification of transfer completion from a ch-0 state managing circuit 116, such parameter controlling circuit instructs a lock set register 115 to release the lock in accordance with the setting of the unlock set register 118.
摘要:
A data communication system for starting transmission and reception of target data for processing upon recognition that switching between communication modes is completed. The data communication system includes a master communication device and a slave communication device that continuously perform, at a time of switching from half-duplex communication to full-duplex communication, (i) a handshake using a directional control code indicating the switching and a preamble code indicating completion of the switching and (ii) a handshake using the preamble code and an acknowledge code indicating receipt of the preamble code, whereby each of the devices recognizes that the switching between communication modes by the opposite device is completed and starts transmission and reception of the target data.
摘要:
A device and method for encrypting content in an encryption device including a content-key storage section is disclosed. The method includes generating a content-key used for encrypting content based on random numbers and storing the generated content-key in the content-key storage section, encrypting the content-key used for encrypting the content so as to obtain an encrypted content-key and outputting the encrypted content-key to outside of the encryption device, determining whether or not a value of the content-key storage section in its initial state and a current value of the content-key storage section are different, and when it is determined that the value of the content-key storage section in its initial state and the current value of the content-key storage section are different, encrypting the content using the current value of the content-key storage section as a content-key so as to obtain a second output data and output the second output data to outside of the encryption device, wherein, for the determination step, a register stores a value of the content-key storage section at the time that said register receives a Power On Reset (POR) signal, and wherein the POR signal is a signal which pulses only once immediately after power-on or immediately after reset, so that the content-key storage section is in an initial state immediately after a corresponding power-on or reset of the encryption device.
摘要:
A copyright protection system comprises an encryption device and a decryption device. Cryptographic communication is performed between the encryption device and the decryption device using a contents key. The encryption device includes a contents storage section for storing contents, a first contents key generation section for generating the contents key based on a second decryption limitation obtained by updating a first decryption limitation, and a first encryption section for encrypting the contents using the contents key and outputting the encrypted contents. The decryption device includes a second contents key generation section for generating the contents key from the second decryption limitation, and a first decryption section for decrypting the encrypted contents using the contents key generated by the second contents key generation section.