You may find some articles related to the subject on http://www.ens.fr/~petersen/publications.html In these papers several extensions of self-certified keys, which make them more competitive compared with certificate-based keys are presented. The main features of self-certified keys lie in their easy availability and accessibility. Other parameters than system parameters are not required to be authentic. Therefore large databases with certified public keys (TTPs) are not needed any more. However, small lists with the authentic public keys of the certification authorities are still needed. The properties of self-certified keys are: -- Determination of a public key without an authentic public directory (TTP). -- Non-repudiation of public keys. -- Efficient verification of a single certificate. -- Efficiency in verification of hierarchical certificates vs. batch signatures -- Importance of key propagation. -- High security of self-certified keys. Theodor Schlickmann