Public Key Infrastructure definition cryptography, communications
(PKI) A system of public key encryption using digital certificates from Certificate Authorities and other registration authorities that verify and authenticate the validity of each party involved in an electronic transaction.
PKIs are currently evolving and there is no single PKI nor even a single agreed-upon standard for setting up a PKI. However, nearly everyone agrees that reliable PKIs are necessary before electronic commerce
can become widespread.
US DOD PKI (http://www-pki.itsi.disa.mil/).
US NIST PKI (http://csrc.ncsl.nist.gov/pki/).
IETF PKIX Working Group (http://imc.org/ietf-pkix/).