Wireless Transport Layer Security (WTLS) Software

VOCAL’s software library Wireless Transport Layer Security (WTLS) module provides communication security with the Wireless Application Protocol (WAP). WTLS is the security layer protocol that operates above the transport layer as shown in Figure 1. Contact us to discuss your wireless application requirements.

WTLS

The primary job of WTLS is to provide privacy, data integrity and authentication between applications communicating using WAP. WTLS is based on and provides similar functionality to the Transport Layer Security (TLS) protocol but is optimized for low bandwidth mobile devices. The three major differences between TLS and WTLS are:

• Compressed Data Structures – Packet size was reduced by using bit-fields, discarding redundancy and truncating cryptographic elements when ever possible
• Compressed Certificate Format – The format follows the X.509v3 certificate structure but uses smaller data structures
• Packet Based Instead of Stream Based – TLS is designed to be used over a data stream and a significant part of the design of WTLS was to allow it to be used in a data packet environment so that protocols such
  as Short Message Service (SMS) could be used as data transport.

WTLS Primitives

WTLS has seven service Primitives listed below with their description:

• Unitdata – Primitive for exchanging data between peers when there is an existing secure
  connection between the peers transport addresses
• Create – Primitive for initiation of the establishment of the secure connection
• Exchange – Primitive for public-key authentication or key exchange with the client in the
  creation of a secure connection
• Commit – Primitive for switching to the newly negotiated secure connection once the handshake
  is complete
• Terminate – Primitive for terminating the connection
• Exception – Primitive for information about warning level alerts
• Create-Request – Primitive for the server to request the client to initiate a new handshake

The service Primitives can be one of four different types listed below with their description:

• request – used when a higher layer is requesting a service from a lower layer
• indication – used by the service providing layer to notify the next higher layer of activities related
  to the request type of the peer or to the provider of the service
• response – used to acknowledge receipt of the indication type from the next lower layer
• confirm – used by the service providing layer to report that activity has been completed successfully

WTLS Parameters

The matrix below lists the parameters with each service Primitive and defines the requirement of the parameters
presence in each parameter type. The entries under the types across from the parameters is defined in the list before
the matrix.

• MUST – Presence of the parameter is mandatory and MUST be present
• CONDITIONAL – Presence of the parameter is conditional depending on other parameters
• OPTION – Presence of the parameter is a user option and MAY be omitted
• – A blank space means the parameter is absent
• X – Primitive type is not possible for that service Primitive
• * – The value of the parameter is identical to the value of the corresponding parameter
  of the proceeding service Primitive

WTLS uses algorithms for Key Exchange, Encryption, and Message Authentication Code (MAC) calculations. The tables
below list the specific algorithms along with needed parameter information.