AssetAsset

Security System

Security is about building barriers to protect assets.

What complicates security is the necessity for barrier penetration.

AttackProperAccess

To be secure the barrier holes must be guarded.

Basic Concepts in Barrier Penetration Control

- Can you prove it?

- That which you are permitted to do.

- You should be held responsible.

- Who are you?

Security systems need to be able to distinguish the“white hats” from the “black hats”. This all begins with identity.

What are some common identifiers used in our world?

What is the problem with using people’s names as identifiers?

Access privileges granted to a user, program, or process.†

† Definition from National Information Systems Security

Common authorization tokens:

Security measure designed to establish the validity of a transmission, message, or originator,or a means of verifying an individual’s authorization to receive specific categories of information.†

† Definition from National Information Systems Security

Authentication is often necessary to ensure integrity of origin.

Authentication ... is a basis for trust

Password -- the most common means of authentication

Passwords are vulnerable to attacks. Why?

Uses challenge - reponse protocol

RESPONSE

password:

CHALLENGE

(Encryption required)

Challenge-response systems fail when responses are efficiently discovered.

Give password cracking software a challenge.The conventional wisdom is as follows...

Use first letters from some phrase you can remember.

TtlsH1wwya

Don’t use short passwords (at least 8 symbols).

Include both lowercase and uppercase and digits.

Bracket the password with non-alphanumerics.

#TtlsH1wwya&

Bracket the password with non-printables.

#TtlsH1wwya&

Alt - 0181

cracker algorithm == repeatedlycracker algorithm == repeatedly

token -- small device carried by user(often includes microprocessor, keypad and/or real-time clock)

Challenge-Response Token1) System displays random number which user enters on keypad.2) Card uses keypad input to calculate and display number.3) User enters number in computer which system verifies by same computation.

Time-Based Token1) Card uses internal real-time clock value to calculate and display number.2) User enters number in computer which system verifies with its clock.

HHAD - Hand Held Authentication Device

biometric -- requires special devices to read human features

fingerprints

retinal/iris scans

facial recognition?

voice patterns

Advantages • nothing to remember or to carry• promise of simple use

Disadvantages • imperfect accuracy (1:100,000 at best)• susceptible to physical injury• theft possible (even without direct contact)• not all systems will be consistent

NIST has suggested including two fingerprints and a faceprint on passports.

A few major U.S. airports have tested face recognition software.

In Jan., 2002, a Yokohama math researcher spoofed fingerprints.

A British medical report claims that medications used to treat Glaucoma willalter iris patterns, rendering iris scans useless.

digital certificate -- a certificate authority performs a security checkon a user and grants an electronic certificate (essentially encryption keys)

smartcard -- physically requires reader, contains full microprocessor with cryptographic calculations performed onboard.

Smartcards can store ... private keys biometric data digital certificate user data

Tampering with a smartcard typically renders it useless.

Strength of authentication

Vulnerability to attack

Ease of use

Cost to implement

Interoperability with other systems

...what you _______ (password)

...what you _______ (key, token, smartcard)

...what you _____ (biometrics - fingerprints, retinal scan)

..._______ you are (in secure location, at some terminal)

Assurance the sender of data is provided with proof of delivery and the recipient is provided with proof of the sender’s identity, soneither can later deny having processed the data.†

† Definition from National Information Systems Security

Access

Attacker

User