The Message Integrity Check(s) (one-way hash) of the EDI message.
In the Send Adapter, the MDNMICValue is computed using the algorithm expected in the Received-Content-MIC of the signed receipt. This will be the same as the signature algorithm used for signed messages, or SHA1 otherwise.
In the Receive Adapter, the MDNMICValue is calculated using the algorithm used on the incoming message's signature, or SHA-1 if the incoming message is not signed.
The MIC will be base64 encoded and reported with the algorithm name as specified in RFC 3335; e.g., "w7AguNJEmhF/qIjJw6LnnA==, md5".