We’re designing authentication architecture for external supplier access to our Oracle Fusion Cloud SCM 23C supplier collaboration portal. Currently evaluating SAML federation versus OAuth2 for partner authentication.
Our requirements:
- 50+ external suppliers need access to collaboration features (forecasts, POs, ASNs)
- Suppliers use various identity providers (some have their own SAML IdP, others use basic credentials)
- Need to support both interactive portal access and API integration
- Security team wants federated authentication to avoid managing external user credentials
SAML federation seems ideal for SSO with suppliers who have their own identity providers, but the onboarding complexity is concerning. Each supplier requires bilateral federation setup, certificate exchange, and metadata configuration. For smaller suppliers without SAML capability, we’d need to provide alternative authentication.
OAuth2 with our IDCS as the authorization server could simplify onboarding - suppliers authenticate once and receive tokens for both portal and API access. However, this means we’re managing supplier credentials in our IDCS, which the security team wants to avoid.
Has anyone implemented external partner authentication at scale in supplier collaboration? What are the real-world trade-offs between SAML federation complexity and OAuth2 credential management? Interested in hearing about partner onboarding experiences and any hybrid approaches that worked well.
Having implemented both approaches across multiple supplier collaboration deployments, here’s my analysis:
SAML Federation Support:
Advantages:
- True federated identity - suppliers manage their own credentials
- Strong SSO experience for suppliers with multiple systems
- Eliminates password management overhead for you
- Better for suppliers with strict security policies requiring internal IdP control
- Supports advanced authentication methods (smart cards, biometrics) managed by supplier
Disadvantages:
- Complex bilateral setup (2-4 weeks per supplier for initial configuration)
- Requires technical capability on supplier side (many SMBs lack this)
- Certificate lifecycle management (renewals every 1-3 years)
- Troubleshooting federation issues requires coordination with supplier IT teams
- Doesn’t work well for API-only access patterns
- Metadata updates when either side changes configuration
OAuth2 for API Access:
Advantages:
- Simple onboarding (can be self-service with approval workflow)
- Works perfectly for both interactive and API access
- Programmatic token management for automated systems
- Granular scope control for different access levels
- Easy to revoke access or rotate credentials
- Supports modern authentication flows (PKCE for mobile apps)
Disadvantages:
- You manage external user credentials (password policies, resets, lockouts)
- Requires implementing MFA for adequate security
- Password sharing risk if suppliers use shared accounts
- Credential lifecycle management overhead
- May not satisfy suppliers who require federated identity
Partner Onboarding Complexity:
Real-world onboarding timelines:
- SAML: 2-4 weeks (metadata exchange, testing, certificate validation, attribute mapping)
- OAuth2: Same day to 3 days (account creation, credential delivery, access verification)
Complexity factors:
- SAML requires deep technical knowledge on both sides
- OAuth2 requires robust credential delivery and management processes
- SAML troubleshooting needs access to both IdP logs
- OAuth2 troubleshooting is simpler but more frequent (password issues)
Recommended Hybrid Approach:
Implement a tiered authentication strategy:
-
Strategic Suppliers (20% of suppliers, 80% of volume):
- Use SAML federation with their corporate IdP
- Investment in setup time pays off with better security and user experience
- Formalize federation agreement with SLA for IdP availability
-
Standard Suppliers (60% of suppliers):
- Use OAuth2 with IDCS-managed credentials
- Implement self-service onboarding portal
- Enforce MFA for all portal access
- Provide OAuth2 client credentials for API integration
-
Occasional/Small Suppliers (20% of suppliers):
- Use time-limited access tokens or guest accounts
- Consider just-in-time provisioning for specific transactions
- Limit to read-only collaboration features
Practical Implementation:
For your 50+ suppliers, I’d recommend:
- Start with OAuth2 as the default authentication method
- Build SAML federation capability for the 5-10 largest suppliers who request it
- Use OAuth2 client credentials exclusively for API integration
- Implement self-service supplier onboarding portal to reduce administrative overhead
This approach balances security, operational complexity, and supplier experience while keeping onboarding manageable at scale.
One aspect often overlooked is API access patterns. If suppliers primarily use APIs for automated data exchange (EDI replacements, automated PO acknowledgments), OAuth2 client credentials flow is superior - no user interaction needed, tokens can be rotated programmatically. SAML is great for interactive portal access but doesn’t work well for machine-to-machine API calls. We implemented SAML for supplier portal users and separate OAuth2 service accounts for their integration systems. This dual approach covers both use cases effectively.
We went with SAML for enterprise suppliers and OAuth2 for small suppliers without IdP capability. The hybrid approach works well - about 70% of our suppliers use SAML federation, and 30% use OAuth2 with credentials managed in IDCS. The key is having a clear onboarding process for each path. SAML setup takes 2-3 weeks per supplier but eliminates ongoing credential management. OAuth2 onboarding is same-day but requires password reset workflows and MFA management.
From an operational perspective, SAML federation support is fantastic once configured but the initial setup is painful. We spent significant time troubleshooting certificate issues, metadata mismatches, and attribute mapping problems. Each supplier’s IdP is different, so you can’t have a standard template. OAuth2 is much simpler operationally but then you’re running a credential management service for external users, which brings its own security risks. Consider the long-term support burden - SAML certificates expire and need renewal, OAuth2 requires password policies and account lockout management.