This will be handled by the API library class, but here is a basic description in pseudo-code:
# 56 bytes as explained the_56_bytes = account_no + hash_method + custom_data # associating account with recipient and API account without exposing protected_data = account_id + recipient_email + the_56_bytes # HMAC hash of protected data, using Hash Method and API Account Key hmac_hash = hmac_binary_digest( hash=hash_method, data=protected_data, key=account_key ) # encode in base64 for transportation encoded_identifier = base64_encode(the_56_bytes + hmac_hash) # make valid Message-ID message_id = "<" + encoded_identifier + "@replypush.com>"
What is hmac? It is a code or hash that verifies a message or your data, kind of like a transportable, secure checksum, with private credentials.
This will be used by the replyPUSH server and your Notification code to verify the data.
In the next section reply notification key/values we will cover what is "pushed", when there is a reply.