01-10-2012, 12:11 PM
Security in WAP and WTSL
Security in WAP.ppt (Size: 303 KB / Downloads: 44)
Overview of WAP (Wireless Application Protocol)
Proposed by the WAP Forum (Phone.com, Ericsson, Nokia, Motorola) in 1997.
A wireless communication model, similar to the ISO OSI model
An application environment for deploying wireless services regardless of different types of services, wireless bearers, and devices.
WAP provides a series of security measures
However, there are still various security loopholes in WAP.
WAP Protocols
WAE (Wireless Application Environment): WML, WMLScript
WSP (Wireless Session Protocol) and WTP (Wireless
Transaction Protocol): together provide session layer services
connection oriented sessions or connectionless sessions. Reliable
sessions can be resumed.
WTLS (Wireless Transport Layer Security) (Optional)
Overview of WTLS
Based on TLS
Provides client-server mutual authentication,
privacy, data integrity, non-repudiation
But not the same as TLS
Modifications due to
Narrow-bandwidth communication channel
Much less processing power
Much less memory
High loss ratio
Unexpected disconnections
Restrictions on exported encryption algorithms
Built on top of WDP and UDP (unreliable data transfer)
More security problems
WTLS Sub-Protocols
WTLS contains four sub-protocols:
Handshake protocol:
Client and server negotiate over the security
parameters to be used for later message exchanges
Alert protocol:
Specifies the types of alerts and how to handle them.
warning, critical, fatal
Alerts can be sent by either the client or the server.
Application protocol: interface for the upper layer
Change Cipher Spec Protocol:
Usually used towards the end of the handshake when the
negotiation succeeds
Security Loopholes, Threats, Solutions - WTLS
Has to use keys of small sizes:
40-bit DES -> 35 bits are actually used
Allows weak algorithms to be chosen
exchanges unauthorized messages or unencrypted packet fields, such as alert messages and recode_type field.
Vulnerable to viruses, Trojan horses, and worms.
Saarinen discussed a chosen plaintext data recovery attack, a datagram truncation attack, a message forgery attack, and a key-search shortcut for some exportable keys