A digital signature of a message originator of a message is validated by a processor on message retrieval by a message recipient as a first-tier validation of the message. In response to a successful first-tier validation of the digital signature of the message originator, a transaction token and a message originator identifier are extracted from a message payload of the message. Communication is initiated with a verification service within a secure messaging environment of the message originator as a second-tier validation of the message using the extracted transaction token and the extracted message originator identifier to confirm whether the secure messaging environment of the message originator generated the transaction token and inserted the transaction token into the message payload. Results of the second-tier validation of the message with the verification service within the secure messaging environment of the message originator are determined.