A company offers SaaS, maintaining all customers' credentials and authenticating locally. Many large customers have requested the company offer some form of federation with their existing authenticati

SAML (Security Assertion Markup Language) is a widely adopted standard for federated identity, allowing a Service Provider (the SaaS company) to trust authentication assertions issued by an Identity Provider (the customer's existing authentication infrastructure). This implementation delegates user authentication to the customer's identity system, enabling them to retain full control over user identities and access policies within their organization.

This approach provides an administrative interface for customer-specific user management within the SaaS system, rather than enabling customers to use their own existing identity infrastructure for authentication and authorization.

Replicating passwords or hashes from customer systems to the SaaS platform is a significant security risk and does not establish true identity federation, as the SaaS provider would still be responsible for the primary authentication.

While SOAP is a protocol for web service communication, it does not inherently provide the standardized framework for federated identity assertions and trust relationships that SAML offers, making it too generic to address the specific requirement for federation.