University of Murcia (Spain)

New Security Services Based on PKI

Antonio F. Gómez Skarmeta <skarmeta@dif.um.es>

University of MurciaSPAIN

Agenda Introduction

The UMU IPv6 PKI (UMU-PKIv6)

Distributed Security Policy Management

architecture (DSPM)

Distributed Credential Management System

(DCMS)

Conclusions

Introduction PKIs ... key element for providing security to

distributed and dynamic networks and services Our experience ... based on our own designs and

implementations: An IPv6 PKI (UMU-PKIv6) Two innovative secure distributed services built over this

PKI Distributed Security Policy Management architecture (DSPM)

Based on the concept of policy (set of rules governing choices in the behaviour of one system)

Modifying a policy we can change the behaviour of one system It defines a new network paradigm, based on flexible and

programmable networks Distributed Credential Management System (DCMS)

Difference between the concepts of certificate and identity certificate

Based on SPKI/SDSI infrastructure More suitable for complex and distributed environments

University of Murcia (Spain)

The UMU IPv6 PKI (UMU-PKIv6)

UMU-PKIv6 Description Main Objective ... to establish a high security

infrastructure for distributed systems Main Features:

First PKI supporting the IPv6 protocol Developed in Java running on every Operating System Issue, renew and revoke certificates for every entity

belonging to one organisation Final users can use either RAs or Web browsers to make

their own certification operations LDAPv6 directory support Use of smart cards (file system, RSA or Java Cards) ...

allowing user mobility and increasing security PKI Certification Policy support VPN devices certification support (using the SCEP

protocol) Support for the OCSP protocol and Time Stamp Web administration

UMU-PKIv6 Architecture

WWW Secure Request Server

Data Base

LDAP Server End User

Certification Authority

Registration Authority

Administrator

IPv6 SSL connection

IPv6 Plain connection

SCEP

VPN Device

WWW Secure Request Server

Data BaseData Base

LDAP ServerLDAP Server End UserEnd User

Certification Authority

Certification Authority

Registration Authority

Registration Authority

Registration Authority

AdministratorAdministrator

SCEPSCEP over IPv6

VPN Device

https://pki.ipv6.um.es

University of Murcia (Spain)

Distributed Security Policy Management architecture

(DSPM)

Security Policies There is ...

high interest in policy-based networking, but no complete systems supporting the

specification and deployment of these policies Policies used to manage distributed communication

systems ... “IF certain conditions are present, THEN specific actions are taken”

Security is vital we sign every policy (using X.509 certificates issued by our own PKIv6)

We use policies for managing The UMU-PKIv6 itself Secure IPv6 VPNs

Security Policies for PKIs UMU-PKIv6 policies

Drive the way the PKIv6 itself works Digital implementation of a Certification Practice

Statement (CPS) ... they specify which rules must be applied to requested or existing certificates

Digitally signed (integrity and authentication) normally by the CA private key

Centralised creation process driven by the PKI admin

Distributed use by RAs and other PKI components Categories:

Certification rules Re-issuance rules Revocation rules

Security Policies for PKIs (II)

Information about a Policy

Security Policies for VPNs IPsec

Receiving widespread deployment for implementing VPN

Typical policy-enabled networking service But ...

IPsec policy databases are normally manually-configured

Growing number of Internet applications using VPNs Therefore, a IPsec Policy-Based Network

Management system (PBNM) is clearly needed Our designed and implemented PBNM is divided

in two different components: Policy Definition Process Policy Recovery Process

Security Policies for VPNs (II)

Policy Definition Process IPsec Policy ... “IF conditions include a type of traffic,

IP address, and/or TCP/UDP port, THEN actions should include setting certain level of authentication and encryption of traffic”

Provides a common means of specifying IPsec policies Vendor and platform independent Defined in XML and mapping, using XML style-sheets, onto

every IPsec and IKE (freeware or commercial) implementations

Enables a coordinated control of IP-level security services in every administrative domain

Based on the CIM model (from the IETF/DMTF) ... common data schema for describing management information

Security Policies for VPNs (III)

Policy Definition Process Schema

Administrator

Policy Repository

LDAPPolicyManagement Tool

(Parser XML/LDAP)

CIM-XML

store/retrieve

CIMClient

CIMObject

Manager

Security Policies for VPNs (IV)

Policy Recovery Process It makes use of two kind of entities

Policy Decision Points (PDPs) Policy Enforcement Points (PEPs)

and one IETF-defined integrated framework of standards based on COPS (Common Open Policy Service)

Three scenarios are currently defined COPS IPsec node Non-COPS IPsec node

With SMTP Without SMTP

Security Policies for VPNs (V)

Policy Recovery Process Schema

Non-COPSIPSec Node

SPD/SAD

Policy Repository

LDAPPDP

PEP

retrieve

COPS(PIB)

applicationof policy

retrieve

Scene 1

Non-COPSIPSec Node(Agent SNMP)

Scene 2

SNMP(MIB)

COPSIPSec Node

Scene 3

University of Murcia (Spain)

Distributed Credential Management System (DCMS)

DCMS Motivation Most of those SPKI scenarios are based on

delegation Resource controllers have small ACLs delegating

access to some particular public keys (authorities) Application-dependent approaches try to answer:

How do I encode a certification request? How do I submit the certification request? How do the authorities specify and enforce the

authorization policies? (i.e. who is able to obtain a particular authorization?)

In complex environments, simple command-line (and off-line) applications do not seem to be the right approach

DCMS Motivation (II) It is necessary to address the problems related to

scalability and interoperability. DCMS (Distributed Credential Management

System) DCMS defines: requests, policies, and entities DCMS is divided into:

NMS: SPKI ID Certificates AMS: SPKI Attribute and Authorization

Certificates Entities exchange authorization information using

the AMBAR Protocol (similar protocols are valid too)

Main goal of DCMS: to be application-independent

DCMS-NMS (Naming Management System)

NMS is responsible for certification operations related to SPKI ID certificates

This type of certificates can be used to: link a name to a particular public key (principal) define group membership

NMS can be especially useful when authorization is based on groups of principals NMS can be used by the principals in order to

obtain an ID certificate for group G

ID certificates are issued by naming authorities (NA)

DCMS-NMS Entities

Requestors: They create certification requests Additional certificates can be also attached to

the requests Two types of requestors:

Demanding an ID certificate for a name (subgroups)

Demanding an ID certificate for a public key

DCMS-NMS Entities

Service Access Points (SAP): Requestors use SAPs to submit the certification

requests Several advantages:

Naming authorities can be protected They “know” the appropriate naming authorities Public terminals placed at buildings or

departments

DCMS-NMS Entities

Naming Authorities (NA): NAs are controlled by authorization policies In DCMS, those policies are implemented using

SPKI ACLs Use of certificate chain discovery methods

Input: request, additional certificates, ACL Output: data used to generate the new

certificate

DCMS-NMS Requests and ACL Entries

NMS s-expressions: There is no need for a new syntax (we use the certificate

struct) Main differences:

N can be a (* prefix) form or a (* set) form P can make reference to several principals (* set Q S T) valid is making reference to the intended validity period The request is signed by the requestor, not by the issuer

(cert (issuer (name NA-pk N)) (subject P) (valid …))

(tag (cert-request (issuer (name NA-pk N)) (subject P) (valid …) ))

DCMS-NMS example Request and additional certificate

(sequence (tag (cert-request (issuer (name morpheus-pk Nebuchadnezzar)) (subject neo-pk) ) ) (signature …))

(acl (entry (subject (name morpheus-pk Nebuchadnezzar)) (tag (cert-request (issuer (name morpheus-pk Nebuchadnezzar)) (subject (* set neo-pk trinity-pk switch-pk)) ) ))

(cert (issuer (name morpheus-pk Nebuchadnezzar)) (subject trinity-pk))

ACL

DCMS-AMS (Authorization Management System)

AMS is responsible for the certification operations related to SPKI Attribute and Authorization certificates

NMS and AMS are based on similar entities: Requestors and SAPs are also part of AMS NAs are replaced by AAs (Authorization Authorities)

S-expressions for requests and ACLs are similar to those defined for NMS (including propagation and tags)

There are also two types of requestors: Requestors of authorization certificates Requestors of attribute certificates

DCMS-AMS Role Managers

We need to encode statements like: Psion-AA authorizes the Role Manager RM to request

attribute certificates granting the set of permissions tag-A for group Nebuchadnezzar defined by Morpheus

(acl (entry (subject RM-pk) (tag (cert-request (issuer psion-pk) (subject (name morpheus-pk Nebuchadnezzar)) (tag tag-A) ) ))

DCMS Implementation AMBAR was implemented using Intel CDSA 3.14 DCMS is being implemented also using CDSA

Graphical User Interface (QT libraries) Red Hat Linux 7.1

Several applications: DCMS tag constructors ACL Management Authorities Service Access Points

DCMS Implementation

University of Murcia (Spain)

Conclusions

Conclusions UMU-PKIv6 ... provides a common trustworthy

point for new distributed services, like: DSPM that provides:

New active network management paradigm based on policies (for several scenarios: UMU-PKIv6 and VPNs)

Expressed in XML Based on IETF/DMTF standards: CIM and COPS

DCMS that provides: Certification requests (s-expressions) Authorization policies (SPKI ACLs) Architectural elements

University of Murcia (Spain)

New Security Services Based on PKI

Antonio F. Gómez Skarmeta <skarmeta@dif.um.es>

University of MurciaSPAIN