摘要:
A method and system manage a hierarchy of passwords for users accessing a hierarchy of access control devices. First, a codeword is acquired and a syndrome of the codeword is determined. Next, the codeword is randomly modified with a probability p to produce a modified codeword. The modified codeword is selected and assigned to a user as a password, if the modified codeword is recoverable.
摘要:
A method and system manage a hierarchy of passwords for users accessing a hierarchy of access control devices. First, a codeword is acquired and a syndrome of the codeword is determined. Next, the codeword is randomly modified with a probability p to produce a modified codeword. The modified codeword is selected and assigned to a user as a password, if the modified codeword is recoverable.
摘要:
Biometric parameters acquired from human forces, voices, fingerprints, and irises are used for user authentication and access control. Because the biometric parameters are continuous and vary from one reading to the next, syndrome codes are applied to determine biometric syndrome vectors. The biometric syndrome vectors can be stored securely while tolerating an inherent variability of biometric data. The stored biometric syndrome vector is decoded during user authentication using biometric parameters acquired at that time. The syndrome codes can also be used to encrypt and decrypt data.
摘要:
Biometric parameters acquired from human faces, voices, fingerprints, and irises are used for user authentication and access control. Because the biometric parameters are continuous and vary from one reading to the next, syndrome codes are applied to determine biometric syndrome vectors. The biometric syndrome vectors can be stored securely, while tolerating an inherent variability of biometric data. The stored biometric syndrome vector is decoded during user authentication using biometric parameters acquired at that time. The syndrome codes can also be used to encrypt and decrypt data. The biometric parameters can be pre-processed to form a binary representation, in which the binary representation has a set of predetermined statistical properties enforced imposed by a set of binary logical conditions.
摘要:
Biometric parameters acquired from human faces, voices, fingerprints, and irises are used for user authentication and access control. Because the biometric parameters are continuous and vary from one reading to the next, syndrome codes are applied to determine biometric syndrome vectors. The biometric syndrome vectors can be stored securely, while tolerating an inherent variability of biometric data. The stored biometric syndrome vector is decoded during user authentication using biometric parameters acquired at that time. The syndrome codes can also be used to encrypt and decrypt data. The biometric parameters can be pre-processed to form a binary representation, in which the binary representation has a set of predetermined statistical properties enforced imposed by a set of binary logical conditions.
摘要:
A method represents a correlated set of images. The correlation can be spatial or temporal. A lossy operation is applied to each image in the correlated set to generate a coarse image. The coarse image is encoded losslessly to yield an encoded coarse image. Each image is also represented by syndrome bits. The combination of the encoded coarse images and the syndrome bits represent the correlated set of images.
摘要:
First biometric parameters are acquired from a user. Input data are encrypted according to the biometric parameters to produce ciphertext. The biometric parameters are encoded using a syndrome encoder to produce a syndrome code. The ciphertext and the syndrome code are associated with each other and stored in a computer readable media so that only the same user can subsequently decrypt the cipher text.
摘要:
A method constructs a code, wherein the code is a large-girth quasi-cyclic low-density parity-check code. A base matrix is selected for the code. A cost matrix corresponding to the base matrix is determined. A single element in the base is changed repeatedly maximize a reduction in cost. A parity check matrix is constructing for the code from the base matrix when the cost is zero, and an information block is encoded as a code word using the parity check matrix in an encoder.
摘要:
A method determines approximate probabilities of states of a system represented by a model. The model includes nodes connected by links. Each node represents possible states of a corresponding part of the system, and each link represents statistical dependencies between possible states of related nodes. The nodes are grouped into arbitrary sized clusters such that every node is included in at least one cluster and each link is completely contained in at least one cluster. Messages, based on the arbitrary sized cluster, are defined. Each message has associated sets of source nodes and destination nodes, and a value and a rule depending on other messages and on selected links connecting the source nodes and destination nodes. The value of each message is updated until a termination condition is reached. When the termination condition is reached, approximate probabilities of the states of the system are determined from the values of the messages.
摘要:
A code to be decoded by message-passing is represented by a factor graph. The factor graph includes variable nodes indexed by i and constraint nodes indexed by a connected by edges for transferring messages mi→a outgoing from the variable nodes to the constraint nodes and messages ma→i incoming from the constraint nodes to the variable nodes. The messages mi→a are initialized based on beliefs bi of a received codeword. The messages ma→i are generated by overshooting the messages mi→a at the constraint nodes. The beliefs bi are updated at the variable nodes using the messages ma→i. The codeword is outputted if found, otherwise, the messages mi→a are updated using a correction for the overshooting.