In an example, a system and method are provided for validating the sender of a message, such as an e-mail, text message, voice mail, network message, internet posting, or other electronic message. An authenticity server engine may first prescreen the message with anti-spam, anti-malware, and other filters. The screened message is then provided to the end user. If the end user deems the message suspicious, he may request additional validation. The authenticity server engine may then apply an example four-phase validation scheme, including analyzing header data for consistency with the message body, analyzing public data sources, analyzing private data sources, and receiving a result of an off-channel challenge to the sender. The server may then assign the message a sender validity confidence score.