Abstract: Systems and methods for reducing the number of challenge messages that are sent in response to an incoming message in situations where the incoming message is likely not unsolicited. The systems and methods include evaluating the behavior of a sender with regard to one or more federated messaging services and determining if the sender is approved or unapproved. If the sender is approved, the incoming message is deliver to a recipient's inbox without issuing a challenge message. Unapproved senders are required to respond to a challenge message.

Abstract: Systems and methods for allowing challenge messages to be sent directly to a recipient's inbox where normally the challenge message would be sent to a pending folder or deleted. Challenge messages sent between federated messaging services contain a federated token which can be identified, authenticated and validated to determine whether the challenge message should be sent to a recipient's inbox. The federated token can include an authentication portion and a validation portion. Authentication methods for the authentication portion can include, for example, checksums, salts, hashes and digital signatures. Once a federated token is authenticated by decrypting the authentication portion according to one or more of these authentication methods, the federated token is validated by determining the defined use-base and determining whether the receipt of the federated token satisfies the defined use.

Abstract: A recipient computer system may receive one or more electronic messages. The recipient computer system may send one, two, or more challenge messages to the sender of the electronic messages in determining whether to deliver the electronic message. The recipient computer system may accept or reject an electronic message based on the response, or lack of response, to the challenge messages. The recipient computer system may send two or more challenge messages at intervals. A sender computer system may record activity of the sender computer system for a recipient computer system to use in determining whether to deliver an electronic message. A sender computer system may provide a summary of that activity with an electronic message. A sender computer system may provide an authorization key for a recipient computer system to use in determining whether to deliver an electronic message. The authorization key may be generated by a third party.