You may have heard that Google recently was able to compromise the SHA-1 hashing algorithm, which is commonly used in AS2 communication.  You can review these helpful articles below on the SHA-1 vulnerability:

https://security.googleblog.com/2014/09/gradually-sunsetting-sha-1.html

https://security.googleblog.com/2017/02/announcing-first-sha1-collision.html

https://techcrunch.com/2017/02/23/security-researchers-announce-first-practical-sha-1-collision-attack/

We are asking customers to either use a more secure, supported hashing algorithm, such as SHA2 (224 bit, 256 bit, 384 bit or 512 bit), or migrate to another of Dsco's integration options, such as flat file exchange or API integration. All customers currently using SHA-1 should make the switch by February 1, 2018.

Due to security considerations, any AS2 integration still using SHA-1 after February 1, 2018 will be removed.  

Thank you for your understanding and help keeping AS2 communications secure. If you have any questions, please don't hesitate to contact our support team at support@dsco.io.

Best regards,

The Dsco Team