A SAML binding specifies how SAML protocol messages are mapped and transported over standard communication protocols. It acts as a bridge, defining the rules for encapsulating SAML messages within other protocols like SOAP, HTTP POST, or HTTP Redirect. For instance, the SAML SOAP binding defines how to place SAML request and response messages within the body of a SOAP message, enabling communication between a Service Provider and an Identity Provider over a SOAP-based web service.

B. SAML assertion: An assertion is the data payload containing security statements (e.g., authentication, attributes), not the specification for how to transport it.
C. SAML profiles: A profile defines a specific use case (like Web Browser SSO) by combining assertions, protocols, and bindings, but it is not the component that maps to the transport layer itself.
D. SAML protocol: A protocol defines the structure and content of the SAML messages (e.g., AuthnRequest, Response), not how those messages are carried by other protocols.

1. OASIS

"Security Assertion Markup Language (SAML) V2.0 Technical Overview"

March 2005.

Section 2.4

Bindings

Page 10: "A SAML binding is a mapping of a SAML protocol message onto standard messaging formats and/or communications protocols. For example

the SAML SOAP Binding specifies how a SAML message is encapsulated in a SOAP 1.1 message..." This directly defines a binding as the component responsible for mapping SAML messages to protocols like SOAP.

2. OASIS

"Bindings for the OASIS Security Assertion Markup Language (SAML) V2.0"

OASIS Standard

15 March 2005.

Section 1

Introduction

Lines 100-101: "This specification defines a set of bindings for use with SAML V2.0 protocols. A binding is a mapping of a SAML protocol message onto standard messaging formats and/or communications protocols."

Section 3

SAML SOAP Binding: This entire section is dedicated to specifying the rules for "the transport of SAML request and response messages within SOAP 1.1 messages."

3. Cisco

"SAML SSO Deployment Guide for Cisco Unified Communications Applications

Release 14SU2"

15-Feb-2024.

Chapter: SAML SSO Solution

Section: SAML Components: This guide describes the SAML components in a Cisco environment. It explains that the "SAML protocol defines the messages that are exchanged" and implicitly relies on bindings (like HTTP POST) to transport these messages between the Identity Provider and the Service Provider (Cisco UC application).