| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide different levels of security so that users can decide the security level of their own communications. <P>SOLUTION: Users can choose a low level of security and maintain the security overhead as low as possible. Alternatively, they can choose higher levels of security with attendant increases in security overhead. The different levels of security are created by the use of one or more of two keys: an encryption key is used to encrypt plaintext data in a delta and a message authentication key is used to authenticate and insure integrity of the data. Two keys are used to avoid re-encrypting the encrypted data for each member of the telespace. In another embodiment, subgroups called "tribes" can be formed within a telespace and each tribe adopts the security level of a telespace in which the tribes reside. <P>COPYRIGHT: (C)2012,JPO&INPIT |
