Businesses of all sizes need secure and scalable methods for sharing information, but it's not always clear what the best protocols and solutions are for each use case. Two of the most commonly used data transfer protocols are Applicability Standard 2 (AS2) and Secure File Transfer Protocol (SFTP).

While AS2 is a protocol-based standard that's most often used for data transfers that require proof of receipt, SFTP is a more commonly used protocol for secure, scalable file transfer.

Before we dive in, here's a quick look at the key differences between them:

  • AS2 operates on the HTTP or HTTPS foundational protocol and SFTP runs on the SSH protocol.
  • AS2 relies more heavily on digital signatures and certificates, which makes it a great option for non-repudiation requirements.
  • AS2 is not always considered a protocol but rather a specification that runs on a protocol; SFTP is a protocol.
  • SFTP works for both B2B and B2C data transactions, whereas AS2's digital certificate requirements make it almost exclusive to B2B interactions.
  • SFTP is typically a better option for large file and document transfers.

In this article, we will discuss when it is best to use AS2 and SFTP, how each protocol works, and the benefits of each. We'll also explain what organizations need to consider when deciding which one is the right fit for their needs. 

Table of Contents

What Is AS2?

Applicability Statement 2 (AS2) is a networking protocol and secure data exchange standard that is built on the Hypertext Transfer Protocol (HTTP). With the support of HTTP, AS2 is used to securely transport and share structured data across business environments.

AS2 is most frequently used in industries like e-commerce and retail that require proof of compliant data transfers. With its reliance on digital signatures and message disposition notifications (MDNs), AS2 provides proof of whether or not the sender sent a message and if the receiver received it.

How Does AS2 Work?

To begin the AS2 exchange process, users must first make sure data is in a compatible format, such as EDI or XML. Then, the sender will send their message over the HTTP protocol with their personal digital signature, which will indicate to the receiver who the message is from and that it has been authenticated.

EDI is typically encrypted with a public key that the recipient can only decrypt with their private key. Though not necessary, many senders ask for a receipt called a message disposition notification (MDN).

The MDN will automatically be generated by the receiver's server and sent back to the sender through the same HTTP protocol and then verified with the receiver's original public key.

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Benefits of AS2

AS2 is a highly secure and collaborative approach to electronic data transfers that is used by businesses of all backgrounds. However, it's particularly favored by retail organizations that must meet EDI standards and require proof of receipt for multiple transactions.

The main reason most users select AS2 is its compatibility with non-repudiation requirements. It's both secure and communicative, using mandatory digital signatures to meet non-repudiation rules; both the sender and the recipient must acknowledge whether or not they've sent or received a message.

What Is SFTP?

Secure file transfer protocol (SFTP) is a more secure version of FTP and is used when stronger encryption and security features are necessary for file transfers. It relies on the secure shell (SSH) networking protocol and both private-key and public-key encryption.

Many people choose to use SFTP for file-sharing because it maintains high levels of security and is compatible with various compliance regulations. It's also less difficult and resource-intensive to set up than many other protocols. It can also be used to share data with either business or non-business users, making it a more flexible data and file-sharing mechanism.

How Does SFTP Work?

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SFTP works through a client-server relationship that is set up on the Secure Shell protocol. To configure SFTP, the client will need to initiate a connection with the server in question. From there, the client and server will establish encryption standards for the upcoming file exchange and authenticate each other before moving forward.

The authentication process is what sets up the secure channel between the client and server. Now, the client can send SFTP commands to the server for various tasks, including uploading files based on their location. A transaction is complete once the server accepts the client's request and decrypts the message.

Benefits of SFTP

Similar to AS2, SFTP aligns with many security and compliance requirements with its focus on data encryption and frequent data integrity checks. It's also a flexible protocol option that allows users to transfer multiple files to multiple servers at once, even non-business servers.

In general, SFTP is considered a flexible and easy-to-manage protocol that doesn't require highly technical users to set up and manage it. It's also one of the most frequently used protocols, which means the sender and the receiver are more likely to be familiar with SFTP procedures.

AS2 vs. SFTP: Key Similarities

Here are the key similarities between AS2 and SFTP:

  • Both AS2 and SFTP frequently use public- and private-key cryptography.
  • Both protocols are designed for secure data exchanges and can support different regulatory compliance requirements.
  • Both AS2 and SFTP can be used for B2B data and file exchanges.
  • Both are encrypted at the transport layer.
  • Both have built-in mechanisms to track and mitigate any attempts at tampering with data, which protects data integrity.

Looking to learn more? Compare SFTP to FTP or compare SFTP to additional protocols.

AS2 vs. SFTP: Key Differences

Here are the key differences between AS2 and SFTP:

  • Depending on who you ask, AS2 may not be considered a protocol like SFTP. Instead, many refer to AS2 as a collection of rules for how EDI data can be transported over the HTTPS protocol.
  • AS2 operates on the HTTP or HTTPS foundational protocol and SFTP runs on the SSH protocol; HTTPS has more of a cross-network focus while SSH works well for both internal and cross-network data and file transfers.
  • AS2 helps users meet non-repudiation requirements with MDN, digital signatures, acknowledgments, and other features that help users track sent and delivered messages.
  • AS2 can't really be used for consumer-facing transactions because of the digital signature and MDN features; SFTP is more flexible and can be used to share and receive data from non-business entities.
  • SFTP is easier to set up and scale for multiple transactions, which makes it a more frequently selected option, especially for large and frequent transfer projects.




  • Many consider AS2 a collection of rules for EDI data transport
  • Often referred to as a protocol

Foundational Protocol

  • Operates on the HTTP or HTTPS protocol
  • Runs on the SSH protocol

Network Focus

  • More of a cross-network focus
  • Works well for both internal and cross-network data transfers

Non-Repudiation Features

  • Provides MDN, digital signatures, and acknowledgments for tracking
  • Does not inherently provide such features

Consumer Transactions

  • Not suitable due to digital signatures and MDN features
  • Flexible; can be used with non-business entities

Setup and Scalability

  • More complex to set up
  • Easier to set up and scale, preferred for frequent transfers

AS2 vs. SFTP: Which Protocol Is Best?

If you're working in a highly regulated industry or are otherwise interested in maintaining a detailed ledger of receipts, AS2 is probably a better fit. However, if you require a protocol that's more scalable, easier to set up, and generally more affordable, SFTP may be the better option.

Most businesses opt for a protocol like SFTP, especially because of how well it works with ETL and CDC, but it all depends on your specific requirements for file and data transfers. offers several features that support smoother SFTP operations. Bi-directional data sharing, hundreds of data transformation components, and many automation features are available to streamline the data preparation and SFTP process.

Try Today for Secure & Reliable Data Sharing is a strong solution for businesses that need to automate SFTP file-sharing and data ingestion processes. Want to learn more? Book a demo with the team today.