GROUP ENCRYPTION METHODS AND DEVICES

摘要

The present invention improves on prior art group encryption schemes by encrypting an alias of a recipient's public key instead of the public key itself. A Group Manager publishes the encryption of the alias,the corresponding public key and a corresponding certificate on a public database DB. The alias is a resulting value of a suitably chosen function f on the public key, and can be viewed as a hash of the public key. This can allow a significant decrease in the size and cost of the resulting construction as the alias can be made smaller than the public key. In particular, there is no need to apply the second encryption scheme as many times as there are group elements in the recipient's public key.