The Hierarchical Trust Model

PGP Certificate Server details• Fast, efficient key repository

– LDAP, HTTP interfaces• Secure remote administration

– “Pending” area for unverified keys– Server database replication– PGPtls connection between client and server

• Database replication provides corporate branch offices with fast access to public keys– via Replication Engine

• Solaris, Windows NT

PGP Certificate Server

• Allows large-scale deployment of public keys for use in intranets and the Internet

• Allows centralized storage & management of digital certificates

• Efficient LDAP/HTTP certificate distribution and searches• Support for client synchronization of keys• Scalable from small groups to multi-national corporations• Customizable policy management rules• Host of features: remote access, administration, logging,

replication engine to synchronize multiple servers• Seamless integration with PGP client programs• Windows NT 4.0 or Solaris 2.51 or above

PGP Certificate Server for NT

Control Monitor Event Log

Certifying Authority

Encrypted Text

EncryptDecrypt

Private Key

Certifying Authority

Public Key

Process for Validating Keys

• User generates key, sends to server automatically• Key is held in ‘pending area’, not added to main

server database• Administrator periodically checks pending area

and manually verifies keys contained within to ensure authenticity

• Admin reconstitutes shared signing key and validates keys

• Keys are then added to server and made available

Key splitting and PGPtls• High-risk keys can be split and shared

– “N of M” shares required to reconstitute key for use• ADKs, Corporate Signing Keys are good

candidates for splitting• Share holders don’t have to be present!

– Secure connections between clients with PGPtls allow shareholders to be anywhere in the world and still reconstitute a split key

PGP Certificate Server for central certificate storage LDAP-based, both x509 and PGP spt Scaleable: certserver.nai.com vends over 500,000 certificates aloneExtensible searching mechanism

PGP Certificate Server for central certificate storage– Provides scalability to PGP applicationsProvides scalability to PGP applications– Supports hundreds of thousands of certificates

– certserver.nai.com vends over 500,000 certificates– LDAP-based

PGP Certificate Server

• Large-Scale Deployment of Public Keys – Efficient LDAP & HTTP Certificate Distribution– Scalable to Very Large Enterprises

• Customizable Policy Management Rules• PKI Features: Remote Access, Administration,

Logging, Replication Engine, Multiple Trust Models, Validity Checking, Data Recovery

• Seamless Integration with PGP Clients

1. Alice creates message for Bob

2. Alice searches for Bob’s public key on her local key ring

3. Bob’s key not found, auto-import key from CertServer

5. Alice’s Client stores Bob’s key locally

4. CertServer returns Bob’s valid key

6. Alice encrypts to Bob’s key & sends...

Alice

6

4

CertServer

Bob

1,2,5 3

PGP Certificate Server Operations

Need: Scalable and manageable PKI

Solution: PGP Certificate Server

•Scalable and replicated storage of public keys

•Integrated policy management

•Seamless integration with client

PGP Enterprise Security Products