AS2 (Applicability Statement 2) is a widely adopted protocol for secure and reliable exchange of EDI and business documents over the Internet. In SAP B2B integration scenarios, AS2 is a preferred communication method for transmitting purchase orders, invoices, shipping notices, and other transactional documents with external trading partners.
Understanding key components of AS2 communication — particularly digital certificates and Message Disposition Notifications (MDNs) — is essential for SAP professionals to implement, troubleshoot, and optimize AS2 interfaces effectively.
AS2 is a specification that enables the secure and reliable transmission of business data using HTTP or HTTPS. It leverages:
Digital certificates form the security foundation of AS2 communication. They serve multiple purposes:
MDNs are acknowledgments sent by the receiving AS2 system to the sender indicating the processing status of the transmitted message.
An MDN includes:
processed (success) or failed (error).Certificate Exchange
Exchange public certificates with trading partners and import them into your SAP AS2 communication setup.
Configure AS2 Communication Channels
In SAP PI/PO or CPI, set up AS2 sender and receiver communication channels specifying:
Set Up MDN Handling
Ensure that MDNs are properly requested, received, and processed.
Test and Monitor
Use test messages to validate encryption, signatures, and MDN flows. Monitor logs for errors.
Use Strong Encryption and Signing Algorithms
Adopt recommended cryptographic standards such as SHA-256 and AES-256.
Maintain Certificate Validity
Track expiration dates and plan renewals ahead of time.
Secure Private Keys
Store private keys securely and restrict access.
Enable Signed MDNs
Signed MDNs enhance trust and non-repudiation.
Log MDN Status
Maintain detailed logs to track MDN receipt and message delivery status.
Handle MDN Failures
Implement retry and escalation procedures for missing or failed MDNs.
| Issue | Possible Cause | Resolution |
|---|---|---|
| Message rejected by partner | Certificate mismatch or expired | Verify certificates and update if necessary |
| MDN not received | Network or configuration error | Check MDN endpoint and firewall settings |
| Signature verification failed | Wrong certificates or corrupted data | Validate certificates and message integrity |
| Decryption failure | Incorrect encryption key or certificate | Confirm encryption keys and certificates |
AS2 communication is a cornerstone of secure B2B integrations in SAP environments. Mastery of digital certificates for encryption and signing, combined with effective handling of MDNs, ensures reliable, trusted data exchange with external partners.
By properly managing certificates and MDN configurations, SAP integration specialists can guarantee message confidentiality, authenticity, and delivery confirmation—meeting both technical and compliance requirements for modern B2B collaboration.