SPKI

SPKI (SimplePublic Key Infrastructure) [2,  1] was developed starting in1995 to remedy shortcomings [3] in the existing IDcertificate definitions:X.509and PGP (Pretty Good Privacy). It provided the first authorizationcertificatedefinition [4,  5]. Originally, SPKI used no names for keyholders but, afterthe merger with SDSI (Simple Distributed Security Infrastructure), nowincludes both named keyholders and named groups or roles – specifyingauthorization grants to names and definitions of names (membership in namedgroups).

In public-key security protocols, the remote party (the prover) in a transaction is authenticated via public key cryptography. Upon completion of that authentication, the verifierhas established that the prover has control over a particular private key – the key that corresponds to the public key the verifier used. This public key is itself a good identifier for the prover. It is a byte string that is globally unique. It also has the advantages of not requiring a...