Comprehensive Guide to AS2 Protocol

What is AS2?

AS2 (Applicability Statement 2) is a protocol used to securely exchange business documents over the internet. It is widely used for electronic data interchange (EDI), where businesses exchange documents like purchase orders, invoices, and shipping notices.

Key Features of AS2

• Security: AS2 provides encryption, digital signatures, and certificates to ensure that the data is secure and can be trusted.
• Data Integrity: By using digital signatures, AS2 ensures that the data sent is not altered during transmission.
• Non-repudiation: AS2 guarantees that the sender cannot deny having sent a message, and the receiver cannot deny having received it.
• Real-time Transmission: AS2 allows for real-time communication, making it suitable for time-sensitive transactions.
• Message Disposition Notification (MDN): AS2 supports MDNs, which are acknowledgments sent back to the sender, confirming the receipt and integrity of the message.

How AS2 Works

AS2 (Applicability Statement 2) works by facilitating the secure exchange of electronic documents over the internet using standard HTTP/S protocols. Here’s a step-by-step overview of how AS2 works:

1. Document Preparation

The sender prepares the business document, which could be an EDI message (e.g., an invoice or purchase order) or any other type of data file (like XML, CSV, or plain text).

2. Message Digest

Calculate the file’s digest using an algorithm like SHA-1, SHA-256, or MD5. In the AS2 protocol, this digest is referred to as the Message Integrity Check (MIC). After calculating the MIC, the sending partner will store this value in their system, such as in a database or another storage mechanism, for future reference.

3. Encryption and Signing

Encryption: The packaged data is encrypted using the recipient’s public key, ensuring that only the intended recipient can decrypt and read the content. Digital Signature: The sender signs the document using their private key. This signature verifies the sender’s identity and ensures the data’s integrity (i.e., that it hasn’t been altered during transmission).

4. Transmission

The encrypted and signed message is transmitted over the internet using the HTTP or HTTPS protocol. The transmission typically occurs via a direct point-to-point connection between the sender’s and receiver’s AS2 servers.

5. Reception and Verification

Decryption: The recipient’s AS2 server receives the message and decrypts it using their private key. Signature Verification: The recipient verifies the sender’s digital signature using the sender’s public key. This step ensures that the message was sent by the claimed sender and has not been tampered with during transmission.

6. Processing and Acknowledgment

The recipient processes the document according to their internal systems and business rules. Message Disposition Notification (MDN): The recipient sends an MDN back to the sender. This acknowledgment can be sent immediately or after the document has been successfully processed. The MDN confirms receipt and verifies the integrity of the message. The MDN itself is signed, providing non-repudiation for the acknowledgment.

7. Error Handling

If the transmission fails, or if the recipient’s server encounters an issue (e.g., signature verification fails), an error message is sent back to the sender, allowing for corrective actions.

Who uses AS2

AS2 is widely adopted in industries that require secure and reliable business-to-business (B2B) communication, especially for EDI transactions.

AS2 is commonly used across various industries, particularly in sectors where secure and reliable business-to-business (B2B) communication is critical. Here are some of the main users of AS2:

1. Retail

• Large Retail Chains: Companies like Walmart, Target, and Amazon require their suppliers to use AS2 for the electronic exchange of purchase orders, invoices, and shipping notices.
• Suppliers and Manufacturers: Suppliers to large retailers use AS2 to comply with the EDI requirements set by the retailers, ensuring seamless communication and transaction processing.

2. Logistics and Transportation

• Freight Forwarders and Carriers: Companies in logistics use AS2 to exchange shipping instructions, booking confirmations, and customs documentation securely with partners and clients.
• 3PL (Third-Party Logistics) Providers: These companies often use AS2 to communicate with their clients and ensure timely and accurate information exchange.

3. Manufacturing

• Automotive Industry: Major automotive manufacturers like General Motors and Ford use AS2 to exchange production orders, shipping schedules, and inventory information with their suppliers.
• Electronics and Machinery: Companies in these sectors use AS2 to manage supply chain operations, including order processing and inventory management.

4. Healthcare

• Pharmaceutical Companies: These companies use AS2 to comply with regulatory requirements for exchanging sensitive information, such as drug orders and shipment tracking.
• Healthcare Providers: Hospitals and clinics use AS2 to securely exchange patient records, insurance claims, and other medical data with insurers and government agencies.

5. Finance and Banking

• Banks and Financial Institutions: AS2 is used for exchanging financial documents, such as payment orders, statements, and confirmations, between banks and corporate clients.
• Insurance Companies: They use AS2 to handle policy documents, claims, and payment processing securely with their partners and clients.

6. Government Agencies

• Customs and Border Protection: Government agencies use AS2 for the secure exchange of customs declarations, import/export documents, and compliance information with businesses.
• Tax Authorities: AS2 is used for the electronic submission of tax filings, payment data, and other regulatory compliance documentation.

7. Consumer Goods

• FMCG (Fast-Moving Consumer Goods) Companies: Companies in the food, beverage, and household goods industries use AS2 to manage their supply chain operations, including order fulfillment and inventory tracking, with retailers and distributors.

Overall, any organization that requires secure, real-time, and reliable electronic data interchange (EDI) may use AS2 to facilitate communication and transactions with their partners, suppliers, and customers.

Setting up an AS2 EDI connection

Setting up an AS2 connection can be approached differently depending on whether you’re using on-premise software, a cloud solution, or a SaaS model. Here’s how each setup typically works:

On-premises

Traditionally, most software applications have been deployed on-premises within an organization’s data center. AS2 software, in particular, might be installed on physical servers, virtual machines (VMs), or more modern environments like containers or Kubernetes. On-premises software typically operates on Linux or Windows operating systems.

On-cloud

Cloud installations offer a straightforward way to comply with regulatory requirements while hosting applications in a highly available cloud environment. They also enable the use of auto-scaling to ensure optimal availability and performance.

SaaS

Hosted Software as a Service (SaaS) solutions provide AS2 services that can be available within minutes. Users can easily sign up and configure their AS2 settings through a modern web-based interface. These solutions are generally much more cost-effective, particularly for users with lower volumes, as payments are based on actual usage, allowing for scalable capacity as the business expands.

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Akila Ishani

Akila is the Lead UI/UX Engineer at Aayu Technologies producing innovative solutions that bring ultimate user experience to the end-user. She is passionate about Software product design and development, Graphics and Data Visualization. Over 8 years of industry experience she is leading teams to deliver exceptional digital experiences.