AS2 Protocol
Detailed overview of AS2 as an EDI transport protocol, including encryption, digital signatures, MDN receipts and implementation considerations.
AS2 (Applicability Statement 2)
AS2 is one of the most widely used B2B transport protocols for secure EDI communication over the internet. It combines encryption, digital signatures and message receipts to provide confidentiality, authenticity and traceability for business-critical document exchange.
Why AS2 is used with EDI
EDI defines the structure of business messages such as purchase orders, invoices and despatch advice documents. AS2 defines how those payloads are transported between trading partners. In practice, EDI is the business content and AS2 is the secure delivery channel.
Key AS2 capabilities
- encryption based on exchanged certificates
- digital signatures for sender authenticity and non-repudiation
- MDN acknowledgements to confirm receipt
- delivery over HTTP or HTTPS for near real-time partner communication
Implementation considerations
A working AS2 setup typically requires a partner-specific AS2 identifier, certificate exchange, firewall and connectivity alignment, and agreement on the cryptographic and operational parameters used in the connection.
Where AS2 is common
AS2 is especially common in retail, logistics, manufacturing and other partner ecosystems where secure, cost-efficient and auditable document exchange is required. It is often selected instead of traditional VAN-based delivery because it lowers transport costs while preserving enterprise-grade control.