Web security pot

SoL Secure Socket Layer > transport layer security service > Originally developed by Netscape > version 3 designed with public input > subsequently became Internet standara Known as I

Cryptography ana

NetWork Security

Chapter 17

Fourth) Edition

by VViliiam) Stallings

Lecture SIGES ply Lawne Brown

Chapter 17 — Web Secunity

Use your mentality

Wake up to reality

—From the song, | ve Got You under,

My Skin™ by Cole Porter,

Web) Secunity

> Web now widely used by business,

government, individuals

> but Internet & Web are vulnerable

> have a variety of threats

° jntegnity

* confidentiality

° denial of Senvice

* authentication

> need adged| secunty mechanisms

SoL (Secure Socket Layer)

> transport layer security service

> Originally developed by Netscape

> version 3 designed with public input

> subsequently became Internet standara Known as ILS (iransport Layer Secunity)

» uses ICP to provide a reliable end-to-

end service

> SSL has two layers of protocols

Where SSL Fits

HTTP SMTP POP3 HTTPS SSMTP SPOP3

Secure Sockets Layer

Transport

Network

S

AS

Si ent

SSL Architecture

SSL SSL Change

Handshake | Cipher Spec a jah HTTP

Protocol Protocol ee

SSL Record Protocol

TCP

SSL Architecture

* SSL connection

° a tfansient, peer-to-peer, Communications link

° associated with 1 SSL session

> SSL session

° an association between Client & Server

° created by the Handshake Protocol

© define a Set of Cryptographic parameters

* may be Shared by MUItIDIE SSL connections

SSL Record Protocol Services

> message integrity

° using) a MAC with sharea| secret key

° similar to AMAC put with aiferent padding

> contidentiality

° USING SymmMeNiC Encryption with a shared

Secret key defined by Handshake Protocol

* AES, IDEA, RCZ-40) DES-40, DES, 3DES,

E9)f127222I p.©2 20) p2©2|2c)

» Insszele[s IS Comlorossse) Salers Snenvoer

SSL Record Protocol

Operation

Application Data

Fragment |

Compress 2 ⁄

or

——————————— iS

4

Enc t SKI SOOO

SRK KKK KI SRR

Cx x x x x OO OO ee

Append SSL RRR RRR OOOO DODO ODDS RR

MASAMI APIO

OOOO OOOO KOO

hs IC

“

Record Header Ree RTI XS

SoL Change Cipher spec

Protocol

> one Of 3 SSL specitic protocols which use the SSL Record protocol

> a Single message

> Causes pending state to become

current

> hence updating the cipher suite in use

SSL Alert Protocol

> conveys SSL-related alerts to peer entity

SSA ey

> Warning) Of fatal

> specific alert

> fatal; Unexpected message, bad record mac,

decompression failure, handshake failure, illegal

Ø4f.aITICI€T:

° WafIfIO: Close notity, no GCTLIlIlCaLC, DdQ GCTIIIICLC,

UnSUppoMmed Certificate, certiiicate revoked) Ceniiiicate Expirea, Cenificate UnKnOWn

> compressea & encrypted like all SS data

Sol Hanashake Protocol

> allows server & client to:

© authenticate cach other

© to negotiate encryption & MAC algorithms

° 10 negotiate cryptographic keys to be used

> comprises a series of messages in phases

, Establish Secunty Capabilities

2 woehver Authentication ang Key Exchange

3 6 Client Authentication and Key Exchange

wlan

Hanashake Protoco

Client Server

Phase 1 Establish security capabilities, including

protocol version, session ID, cipher suite, compression method, and initial random numbers

Phase 2 Server may send certificate, key exchange, and request certificate Server signals end

of hello message phase

Phase 3

Client sends certificate if requested Client

sends key exchange Client may send certificate verification

Phase 4 Change cipher suite and finish handshake protocol

Note: Shaded transfers are

optional or situation-dependent

messages that are not always sent

TLS (transport Layer,

SCCU1tV)

Š IE1I†- Sfandard EXEEG 2246 similar to SSLv3

> with minor differences

© in frecoral format version number

° uses IMAC tor MAC

° a pSEUGO-random function Expands Secrets

° has adaitional alert codes

* some Changes in SUPpPoried! ciohers

° Changes In| Ceniiicate tyoes & negotiations

® Changes in) Chy pio) COMpUtations c paadGing