Messaging systems and methods

A computer program product comprising one or more non-transitory computer-readable storage media having stored thereon computer-executable instructions that, when executed by one or more processors of a computer system, cause the computer system to implement a method, comprising:

• establishing a group that includes a plurality of group members, wherein membership in the group establishes a first trust level among the plurality of group members that enables each of the plurality of group members to send and/or receive group messages without a trust challenge;
• establishing a second trust level between one or more subscribers that are not one of the plurality of group members and the group;
• receiving a message from a sender that is intended for the group;
• determining a trust level between the sender and the group based on whether the sender is a group member or a subscriber;
• in response to the sender being a group member and the trust level between the sender and the group is the first trust level, sending the message to the group members;
• in response to the sender being a subscriber and the trust level between the sender and the group is the second trust level, determining if a trust relationship exists between the sender and each member of the group,
• if no trust relationship exists between a particular member of the group and the sender, delivering the message to the particular member of the group only if the sender passes a trust challenge;
• and
• if a trust relationship exists between the particular member of the group and the sender, delivering the message to the particular member of the group without the trust challenge;
• and
• in response to the sender being neither a group member nor a subscriber and there is no trust level between the sender and the group, blocking the message from being delivered to the group.

A computer system, comprising:

• one or more processors;
• and one or more non-transitory computer-readable media having stored thereon computer-executable instructions that, when executed by the one or more processors, cause the computer system to implement a method, comprising:
• establishing a group that includes a plurality of group members, wherein membership in the group establishes a first trust level among the plurality of group members that enables each of the plurality of group members to send and/or receive group messages without a trust challenge;
• establishing a second trust level between one or more subscribers that are not one of the plurality of group members and the group;
• receiving a message from a sender that is intended for the group;
• determining a trust level between the sender and the group based on whether the sender is a group member or a subscriber;
• in response to the sender being a group member and the trust level between the sender and the group is the first trust level, sending the message to the group members;
• in response to the sender being a subscriber and the trust level between the sender and the group is the second trust level, determining if a trust relationship exists between the sender and each member of the group,
• if no trust relationship exists between a particular member of the group and the sender˜delivering the message to the particular member of the group only if the sender passes a trust challenge;
• and
• if a trust relationship exists between the particular member of the group and the sender, delivering the message to the particular member of the group without the trust challenge;
• and
• in response to the sender being neither a group member nor a subscriber and there is no trust level between the sender and the group, blocking the message from being delivered to the group.