Abstract: A method of selecting a network path for a network coding communication includes initializing a length of each of links; searching for an independent path from a source node to one of target nodes based on the length of each of the links; multiplying a predetermined factor to the length of each of the links used in the independent path; repeating the searching and the multiplying for all the target nodes; extracting the links and the nodes used in the independent path; generating a subgraph with the links and the nodes extracted at the extracting; and selecting the network path based on the subgraph.

Abstract: A communication system includes a source node for transmitting data and general nodes that function as relay nodes for relaying the data or destination nodes for receiving the data. Data encoding is performed in each node of the communication system. The source node is linked to the general nodes by one or more independent paths. The number of independent paths from the source node to each of the general nodes is counted. A tap-proof index is calculated based on the maximum number of independent paths and the size of a set of elements formed by the encoded data. The security level against tapping is determined according to the value of the tap-proof index.

Abstract: A method of selecting a network path for a network coding communication includes initializing a length of each of links; searching for an independent path from a source node to one of target nodes based on the length of each of the links; multiplying a predetermined factor to the length of each of the links used in the independent path; repeating the searching and the multiplying for all the target nodes; extracting the links and the nodes used in the independent path; generating a subgraph with the links and the nodes extracted at the extracting; and selecting the network path based on the subgraph.

Abstract: A communication system includes a source node for transmitting data and general nodes that function as relay nodes for relaying the data or destination nodes for receiving the data. Data encoding is performed in each node of the communication system. The source node is linked to the general nodes by one or more independent paths. The number of independent paths from the source node to each of the general nodes is counted. A tap-proof index is calculated based on the maximum number of independent paths and the size of a set of elements formed by the encoded data. The security level against tapping is determined according to the value of the tap-proof index.

Abstract: The present invention provides a transmission line encoding/decoding system wherein encoding is effected in such a manner that an overhead bit which indicates whether or not a slot, all the bits of which are "0" bits (hereinafter referred to as an all-"0" slot), is present among a plurality of slots constituting in combination one block and is set in a predetermined slot in the block, and if there are all-"0" slots, a slot information bit which indicates the slot position of at least one all-"0" slot is set and at least one all-"0" slot the position of which is indicated by the slot information bit is deleted, and wherein decoding is effected in such a manner that whether or not an all-"0" slot was present in one block before the encoding process is judged on the basis of an overhead bit set at a predetermined position in the block of the received data, and if it is judged that there was an all-"0" slot, the slot information bit indicating the slot position of the all-"0" slot that has been set in the receive