- Identity bridging (e.g., from HTTP Basic Auth to SAML)
- Transport mediation (e.g., between HTTP and MQ Series)
- Protocol and content based security (e.g., HTTPS, WS-Signatures, WS-Encryption)
- Message inspection (e.g., for SQL Injection, Viruses, and other malware)
- Interface Virtualization
- Transformation, Schema Validation
Such functions make is easy and cost effective for enterprises to integrate with their trading partners is a secure manner. Here's a good article for best practices using XML-Gateways.