This paper presents a survey of key evolving cryptosystems in the public key setting, focusing on two main approaches: ‘forward security’ and ‘intrusion resilience’. The essential feature of this design strategy is that the secret key changes over time, while the corresponding public key remains unchanged. Key evolving cryptosystems can limit the damage caused by an attacker who occasionally le...

Anonymous secret sharing schemes allow a secret to be recovered from shares regardless of the identity of shareholders. Besides being interesting in its own right, this property is especially appealing to guarantee the anonymity of participants when secret sharing is used as a building block of more general distributed protocols (e.g. to anonymously share the secret key corresponding to a publi...

There is a great deal of confusion in the cryptology literature relating to various identity related issues. By “names” (lower case), we are referring to informal, personal ways that we indicate others; by “NAMES” (upper case) we are referring to official ways that we use to indicate others. Both of these concepts are often confused with “identity”, which is something else altogether, and with ...

We introduce the notion of certificate-based encryption. In this model, a certificate – or, more generally, a signature – acts not only as a certificate but also as a decryption key. To decrypt a message, a keyholder needs both its secret key and an up-to-date certificate from its CA (or a signature from an authorizer). Certificate-based encryption combines the best aspects of identity-based en...