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US 8,571,214 B2Granted
Secure network coding for multi-resolution wireless video streaming
AssigneeMassachusetts Institute of Technology
InventorsLuisa Lima, Steluta Gheorghiu, Joao Barros, Muriel Medard, Alberto Lopez Toledo, Joao Vilela
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Abstract
Described herein is a method and system for hierarchical wireless video with network coding which limits encryption operations to a critical set of network coding coefficients in combination with multi-resolution video coding. Such a method and system achieves hierarchical fidelity levels, robustness against wireless packet loss and efficient security by exploiting the algebraic structure of network coding.
Claims14
A method for streaming video data in a network including a server node, a plurality of relay nodes and one or more receiver nodes, the method comprising:
- performing a one-time key distribution between the source node and each of the one or more receiver nodes;
- dividing the video data into more than one group of pictures (GoP), each of the more than one group of pictures having a predetermined time of duration;
- for each group of pictures (GoP), generating at the source node an n×n lower-triangular matrix A, in which n is the number of layers in the GoP wherein matrix A is used for encoding at the source only and each non-zero entry of matrix A is an element aij chosen uniformly at random from all non-zero elements of the field Fq\{0};
- dividing the GoP into a plurality of vectors b(1) . . . b(w), each of the vectors having K symbols S1-SK in which the kth symbol of each vector belongs to a corresponding one of the n layers in the GoP and wherein the number of vectors created is computed as size of GoP/n;
- encrypting at least one symbol of each vector b(i) for each use of the encoding matrix wherein the output of the operation of a stream cypher is denoted as a symbol P with a random key K as E(P,K);
- applying the encoding matrix A successively to the information symbols to be sent to provide encoded information symbols which comprise a payload of one or more packets;
- encrypting each line of a first matrix A with a corresponding layer key wherein the first matrix A corresponds to a locked coefficients matrix;
- generating an n×n identity matrix corresponding to the unlocked coefficients wherein each of the one or more packets comprise a header and the payload and wherein the header comprises the locked and unlocked coefficients;
- encoding the one or more packets in relay nodes in accordance with a random linear network coding (RLNC) protocol wherein algebraic coding is performed on unlocked coefficients, locked coefficients and payload;
- and the relay nodes identify the layer of a packet by looking at the first non-zero position in the unlocked coefficients, and packets are mixed with packets of the same or lower layers only.
7 more elements
A system for streaming video data in a network, the system comprising:
- (a) a server node for dividing the video data into more than one group of pictures (GoP), each of the more than one group of pictures having a predetermined time of duration wherein for each group of pictures (GoP), the source node generates an n×n lower-triangular matrix A, in which n is the number of layers in the GoP wherein matrix A is used for encoding at the source only and each non-zero entry of matrix A is an element aij chosen uniformly at random from all non-zero elements of the field Fq\{0} and the source divides the GoP into a plurality of vectors b(1) . . . b(w), each of the vectors having K symbols S1-SK in which the kth symbol of each vector belongs to a corresponding one of the n layers in the GoP and wherein the number of vectors created is computed as size of GoP/n and wherein the source node encrypts at least one symbol of each vector b(i) for each use of the encoding matrix wherein the output of the operation of a stream cypher is denoted as a symbol P with a random key K as E(P,K) and applies the encoding matrix A successively to the information symbols to be sent to provide encoded information symbols which comprise a payload of one or more packets and the source node encrypts each line of a first matrix A with a corresponding layer key wherein the first matrix A corresponds to a locked coefficients matrix and generates an n×n identity matrix corresponding to the unlocked coefficients wherein each of the one or more packets comprise a header and the payload;
- (b) a plurality of relay nodes;
- and
- (c) one or more receiver nodes wherein the header comprises the locked and unlocked coefficients and encodes the one or more packets in the relay nodes in accordance with a random linear network coding (RLNC) protocol wherein algebraic coding is performed on unlocked coefficients, locked coefficients and payload and the relay nodes identify the layer of a packet by looking at the first nonzero position in the unlocked coefficients, and packets are mixed with packets of the some or lower layers only.
1 more element
Dependencies are inferred from the claim text.