公开(公告)号：EP1488596A1

公开(公告)日：2004-12-22

申请号：EP03709982.7

申请日：2003-03-14

申请人： British Telecommunications Public Limited Company

发明人： SOPPERA, Andrea

IPC分类号： H04L29/06 ,  H04L9/08

CPC分类号： H04L9/0836 ,  H04L9/0891 ,  H04L63/065 ,  H04L2209/38 ,  H04L2209/601

摘要： A key distribution server maintains a tree of nodes. Members of a group who are allowed access to information are associated with respective leaf nodes of the tree. The information is encrypted with a key comprising a join key field and a leave field, and these are associated with the root node of the tree. The join key is updated each time a member joins the group and the leave field is updated each time a member leaves. Further respective leave keys are associated with the other nodes of the tree. The leave keys of the tree are related so that a member knowing the leave key of its node can work out the leave key of the root node and hence decrypt the information. The key distribution server transmits offset messages to the members to allow them so to calculate the root node leave key. The system of offset messages reduces the amount of communication required between the key distribution server and the group members.

公开(公告)号：EP1481522A1

公开(公告)日：2004-12-01

申请号：EP03702795.0

申请日：2003-02-24

申请人： British Telecommunications Public Limited Company

发明人： SOPPERA, Andrea

IPC分类号： H04L29/06

CPC分类号： H04L63/0823 ,  G06F21/64 ,  H04L63/126

摘要： An authentication method for linked data is provided, which does away with the conventional requirement for secure authentication of every item of data using public key encryption or Message Access Codes. A subscriber to an indexed event announcement channel can access a first item of information which contains pointers to other items of information in which the user might be interested. A hash value of the pointed-to information is also provided in addition to the pointers themselves. In order to provide for authentication of the pointed-to information, the user authenticates the first item of information using a secure heavyweight authentication technique, and then uses the hash values of the pointed-to information contained in the first item of information to authenticate the pointed-to information when the user accesses it.