Transcript PP-/ST-Guide - OCSI

BSI activities in developing PPs
and the BSI-PP/ST-Guide
Frank Grefrath
Bundesamt für Sicherheit in der Informationstechnik /
Federal Office for Information Security
ICCC September 2007
Agenda

BSI-activities in PP-certification

Introduction of the PP “Digitales Wahlstift-System, V. 1.0.1“

Introduction of the BSI-PP/ST-Guide
Frank Grefrath
September 2007
Slide 2
Recently certified PPs in BSI-CC-Scheme

BSI-PP-0031-2007: “Protection Profile Digitales WahlstiftSystem, V. 1.0.1“


The PP defines the minimum requirements for IT-security of
systems for technical assistance in elections on the basis of a
digital election pen
BSI-PP-0034-2007: “Mobile Synchronisation Services
Protection Profile, V. 1.1”

The purpose of such a system is to provide secure remote
access of mobile users (e.g. using a PDA) to e-mail or PIM
(personal information management) services located in a
company’s intranet
Frank Grefrath
September 2007
Slide 3
Recently certified PPs in BSI-scheme

BSI-PP-0035-2007: „Security IC Platform Protection
Profile” (Update of BSI-PP-0002-2001)


The defined TOE is a smartcard integrated circuit which is
composed of a processing unit, security components, I/O
ports (contact-based and/or contactless) and volatile and
non-volatile memories (hardware)
Different PPs for the German electronic health systems
are currently under evaluation
Frank Grefrath
September 2007
Slide 4
Protection Profile for a digital election system
System Overview

A digital election system which is compliant to the PP
serves for electronic assistance in complex elections

The voter makes his votes with a digital pen on a special
kind of paper

The camera of the pen records his votes and then the
data is transferred to a PC

There the data is analysed, the votes are counted
automatically and a protection against manipulation of
the election result is generated
Frank Grefrath
September 2007
Slide 5
Protection Profile for a digital election system
Motivation / Benefit

Voting takes place in a familiar way for the voter making
crosses with a pen on paper

Vote counting can be carried out much faster and easier

Typical failures in manual counting can be avoided

In cases of doubt the electronic election result can be
controlled by manually counting the paper ballots

Complex elections can be conducted without great
manpower requirements
Frank Grefrath
September 2007
Slide 6
Protection Profile for a digital election system
Main IT-Security Features

Recording the votes on the paper ballots with the pen

Transferring the election data to a PC via USB

Storing the data on the PC without being traceable to the
voter

Analysing the votes and dividing them into valid,
doubtable and invalid votes

Judging of the doubtable votes by the scrutineers

Automatic calculation of the election result

Generation and display of a proof of origin

Logging of security relevant events
Frank Grefrath
September 2007
Slide 7
Protection Profile for a digital election system
Physical Boundaries of the TOE

Hardware: Digital election pens and docking stations

Firmware:
Firmware of the digital election pen


Software:
Frank Grefrath
Recording the marks on the paper
TOE application software for

Controlling the pens

Storing of the election data during the election

Judging and counting the votes

Generating a proof of origin

Logging security relevant events
September 2007
Slide 8
Protection Profile for a digital election system
TOE Security Environment

The PP contains assumptions covering the following
aspects:

Usage assumptions resulting from the German election law
 Trustworthy and carefully working administrators and
scrutineers
 Correctly and securely configured PC platform

The TOE counters the following threats:

Disclosure of election data and protocol data

Disturbance and manipulation of the technical procedures

Unrealised manipulation of the election pen and the
election result

Successful tracing between election data and voter
Frank Grefrath
September 2007
Slide 9
Protection Profile for a digital election system
General Regulations

Validity: Valid until June 30th, 2008

CC Assurance level: EAL 3

Combined evaluation:

EAL3-CC-certification by the BSI

Approval by the Physikalisch Technische Bundesanstalt
according to the German election law with source code
analysis and emission measurement
Frank Grefrath
September 2007
Slide 10
BSI PP/ST-Guide
Introduction

CC, Version 3.1

Intended audience for the guide:

PP/ST-readers, with less or without CC-knowledge

PP/ST-writers

Evaluators, certifiers
Frank Grefrath
September 2007
Slide 11
BSI PP/ST-Guide
Structure of the guide

What is the purpose of PPs/STs?
Which role does a PP play when purchasing a
product?

Reading PPs/STs

Writing of PPs in two different methods


Stove-piping method

Explanation method
Writing of STs
Frank Grefrath
September 2007
Slide 12
BSI PP/ST-Guide
Stove-Piping-Method

Procedure:

Determine which SFRs for the TOE and which security
objectives for the operational environment are desired
 Create a single security objective for the TOE for each
SFR
 Create an OSP for each security objective for the TOE
 Create an assumption for each security objective for
the operational environment
 Write the remaining chapters (PP introduction and
conformance claims)
Frank Grefrath
September 2007
Slide 13
BSI PP/ST-Guide
Stove-Piping-Method


Advantages:

Simple and fast method to write a PP

The PP almost automatically meets many of the
requirements of the APE-class
Disadvantages:

The question why the TOE implements the description
of the PP is not answered

The PP merely states on three different levels (TOE
security environment, security objectives, SFRs)
“This is what the TOE does.”
Frank Grefrath
September 2007
Slide 14
BSI PP/ST-Guide
Explanation Method - Overview


Focus is lying on deriving the various items in a PP,
rather than simply stating them.
Procedure (part 1):

Write the conformance claims

Analyse the OSPs
 Analyse the threats

Frank Grefrath
Derive the security objectives for the TOE and the
operational environment including the security
objectives rationale
September 2007
Slide 15
BSI PP/ST-Guide
Explanation Method - Overview

Procedure (part 2):

Derive the SFRs including the Security Requirements
Rationale
 Define the SARs and explain why you have chosen
them
 Write the PP introduction
Frank Grefrath
September 2007
Slide 16
BSI PP/ST-Guide
Explanation Method - Analysing the SPD

Analysing the OSPs


Analysing the threats


Laws, rules, practices or guidelines
Question for definition: What happens when I don't
have a TOE?

What are the assets to be protected?

What are the adverse actions?

Who are the threat agents?
Assumptions will not be defined
Frank Grefrath
September 2007
Slide 17
BSI PP/ST-Guide
Explanation Method - Deriving the objectives

Deriving the security objectives for the TOE and the
operational environment


Frank Grefrath
Purpose:

Providing a high-level, natural language solution of
the problem

Building a bridge between the threats and OSPs
on one side, and the SFRs on the other side
Three questions:

Where will the TOE be placed and can it be
physically attacked there?

What is the purpose of the TOE?

How is the TOE managed?
September 2007
Slide 18
BSI PP/ST-Guide
Explanation Method - Deriving the SFRs

Deriving the SFRs
 Not
yet worked out, but will be added in the next
version
 Considered approach:
 Short introducing statement to CC Part 2
 Different examples for each functional class
 Possibly more detailed explanations to certain
aspects like the definition of access control
policies, information flow policies or an I&A
policy
Frank Grefrath
September 2007
Slide 19
BSI PP/ST-Guide
Publication

The Guide is currently developed by the BSI in a
project

Upon completion the Guide will be published on the
BSI homepage: http://www.bsi.de
Frank Grefrath
September 2007
Slide 20
Contact
Bundesamt für Sicherheit in der
Informationstechnik (BSI) /
Federal Office for Information Security
Godesberger Allee 185-189
53175 Bonn
Frank Grefrath
Tel: +49 (0)228-9582-5838
Fax: +49 (0)228-9582-5477
[email protected]
Frank Grefrath
September 2007
Slide 21