Relay Response (SIM) processing based on POST

[Scott5859]

My transactions are posting to my designated URL and I can access the Request.Form values. My question is how do I know this really came from AuthorizeNet? I want to do some processing based on a successful Payment Form transaction. Thanks

[RaynorC1emen7 · Accepted solution]

http://developer.authorize.net/api/upgrade_guide/

http://www.authorize.net/content/dam/authorize/documents/SIM_guide.pdf

Read the "Using the MD5 Hash Feature"