Electronic Data Interchange (EDI) has long been the staple for B2B structured data transmission. As business further digitizes and evolves, so does the need for secure and efficient EDI protocols to ensure safe transit in a world of threats.

AS2 and SFTP have risen to the fore as secure data transfer protocols for EDI. AS2 is designed strictly for EDI, while SFTP is a general secure file transfer protocol that has proved highly applicable in EDI as well.

While both are designed to safeguard the integrity and confidentiality of your sensitive business data during transit, each comes with distinct features, functionalities, and ideal applications.

This post compares AS2 and EDI with an aim to inform those already familiar with the basics but chasing a more nuanced understanding of both.

AS2 and SFTP feature-by-feature comparison

Nature and purpose

  • AS2: As a specification for EDI transmissions, AS2 orchestrates secure data exchanges over HTTP/S, employing SMIME for message payloads, with built-in encryption and digital signature functionalities.
  • SFTP: An extension of the tried and robust SSH, SFTP provides encrypted command and data channels, ensuring confidentiality and integrity during transactions, and facilitating seamless and secure data transfer. While SFTP doesn’t natively support encryption and digital signatures, enhanced SFTP options like SFTP To Go provide this added functionality.

Encryption and security

  • AS2: AS2 employs a combination of cryptographic algorithms, like DES and 3DES, alongside digital certificates for encryption.
  • SFTP: SFTP makes the most of SSH’s intrinsic encryption capabilities, using cryptographic algorithms like AES and Blowfish, and offers continuous encryption throughout the data transfer process.

Authentication mechanisms

  • AS2: AS2 applies mutual authentication via X.509 certificates to establish a secure, verified communication channel between trading partners.
  • SFTP: SFTP brings diverse authentication mechanisms, ranging from password-based to public key, thus enabling flexible yet secure authentication configurations, including multi-factor setups.


  • AS2: AS2 incorporates Message Disposition Notification (MDN) for explicit non-repudiation, thus substantiating the integrity and origin of the transmitted data.
  • SFTP: SFTP lacks inherent non-repudiation capabilities due to the absence of a standard acknowledgment mechanism analogous to MDN. However, opting for an enhanced SFTP product is the best way to overcome this con. With SFTP To Go, for example, you can set up webhooks, allowing for the customization and implementation of various third-party or tailored acknowledgment/receipt mechanisms.

Integration and implementation

  • AS2: AS2 integration is a far more complex process, as it requires specialized software components for various functions such as certificate management and MDN processing, which is difficult when you have to implement it at scale.
  • SFTP: Benefiting from broader system support and compatibility, SFTP allows for more straightforward implementations and integration into existing system architectures. This broad compatibility often translates into lower operational overheads and a reduced total cost of ownership, as it can leverage existing infrastructure and administrative expertise.


  • AS2: AS2 mandates AS2 compliance for both sending and receiving entities, which may limit interoperability in heterogeneous environments.
  • SFTP: SFTP is adaptable across various systems and platforms due to its universal acceptance and implementation flexibility. This means a more inclusive and extensive interoperability matrix, facilitating smoother and more versatile B2B data exchanges in diversified technological ecosystems.
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AS2 or SFTP: what’s the verdict?

AS2’s architecture is fortified with robust encryption mechanisms and non-repudiation through Message Disposition Notifications (MDNs), thus ensuring secure and verified data transmissions.

Still, the intrinsic complexity and need for specialized software components in AS2's integration process hint at its meticulous and rigid nature, which can prove challenging to navigate in extensive and dynamic tech and business landscapes.

SFTP, on the other hand, embodies versatility and adaptability, fortified by the Secure Shell (SSH) protocol. It facilitates encrypted data exchange across varied systems and platforms with remarkable ease of integration.

SFTP’s universal applicability applies to a wide spectrum of secure data transfer use cases beyond just EDI. To us, SFTP is a clear winner.

To make your choice easier, we’ve summed up the features of AS2 vs. SFTP in the comparison table below.

SFTP To Go: leveling up on SFTP

SFTP may be good, but we’ve leveled it up anyway with SFTP To Go. Here’s how:

  • Fully-managed cloud storage: Eliminates the hassle of maintaining servers and storage for a seamless and efficient experience.
  • Secure and reliable data exchange: Facilitates secure interactions with partners, vendors, and customers without the need for proprietary infrastructure, using standard protocols like SFTP, FTPS, Amazon S3, and HTTPS.
  • Scalability and robust accessibility: Built on an Amazon Web Services (AWS) storage layer, it offers a multi-AZ architecture, ensuring high availability and resilience.
  • Intuitive user interface and integration capabilities: Designed for instant access and ease of use, it allows efficient management of users and files, and integrates seamlessly with other applications through APIs and webhook notifications.
  • Enhanced security features: Comes fortified with advanced security options such as IP whitelisting and two-factor authentication, ensuring the safety of your data.
  • Flexible authentication options: Supports various authentication methods, including password and SSH key-based, providing flexibility and security in user access.
  • Diverse protocol support: Offers support for a variety of protocols, ensuring compatibility and easing migration and integration processes.
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In conclusion

In summary, it's clear that both protocols have their merits. AS2 is tailored for EDI, offering robust encryption and non-repudiation, albeit with a complex integration process.

On the other hand, SFTP, offers versatility across different systems with a relatively straightforward implementation, making it a viable option for not only EDI but a broader range of secure data transfer applications as well.

Solutions like SFTP To Go further enhance the security framework of SFTP by providing additional features, supports, storage, and flexible authentication options.

This amplifies the security posture while retaining the ease of use and integration benefits, posing a compelling choice for secure, efficient, and user-friendly data transmission in diversified business environs.

The choice between AS2 and SFTP comes down to specific business needs, the technical environment, and the nature of the data transfers in question.

By and large, AS2 is better suited to businesses content with high speed but less in terms of functionality—and integrity. For those seeking an enhanced SFTP experience, solutions like SFTP To Go provide additional features for better usability, functionality, and security.

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Frequently Asked Questions

What is the main difference between AS2 and SFTP?

AS2 is primarily designed for transmitting structured B2B data securely over the internet using HTTP/S. In contrast, SFTP is a secure file transfer protocol that operates over SSH. While both are secure, SFTP, especially when paired with solutions like SFTP To Go, offers a more user-friendly and versatile experience.

Is AS2 more secure than SFTP?

Both AS2 and SFTP have robust security features. AS2 offers end-to-end encryption, digital signatures, and MDN receipts. SFTP, especially when utilized through platforms like SFTP To Go, ensures data confidentiality and integrity during transfers, leveraging the trusted SSH protocol.

How do businesses typically use AS2?

Many businesses, especially in the retail sector, use AS2 for B2B communications. However, the evolving digital landscape and the need for versatile solutions have seen a rise in the adoption of SFTP, with platforms like SFTP To Go providing enhanced features.

Can SFTP be used for B2B communications?

Absolutely! SFTP is not only suitable for B2B communications but is also preferred for its ease of use and security. Solutions like SFTP To Go further enhance the experience by offering advanced security and management features tailored to B2B needs.

What are the infrastructure requirements for AS2?

AS2 demands both parties to have an AS2-capable solution, digital certificates, and a stable internet connection. On the other hand, SFTP, especially when integrated with SFTP To Go, simplifies the setup process, making it more accessible for businesses of all sizes.

Do I need special software to use SFTP?

While you do need an SFTP client, platforms like SFTP To Go streamline the process, offering a comprehensive solution that caters to both beginners and experts, ensuring secure and efficient file transfers.