A plurality of sender-driven group messages 770 may correspond to one solution to sending group messages—messages directed to more than one recipient—using the messaging system 750. The sender client device 720-2 may transmit a sender-driven group message to each of the recipient client devices 720-4, 720-5, and 720-6 through an individual submission of each of the sender-driven group messages 770 to the messaging system 750 for each of the recipient client devices 720-4, 720-5, and 720-6. It will be appreciated that more than three recipient client devices may be specified. Each of the sender-driven group messages 770 may be encrypted using an encryption key, specific to each of the plurality of recipient client devices, one encryption key for each from a plurality of encryption keys corresponding to a plurality of recipient client devices. This may prevent the messaging system 750 from reading the contents of any of the sender-driven group messages 770. Because each of the sender-driven group messages 770 was individually addressed to and for delivery to a particular recipient client device, a public key for each of the recipient client devices 720-4, 720-5, and 720-6 may be forwarded from the recipient client devices 720-4, 720-5, and 720-6 to the sender client device 720-2 by the messaging system 750, with each of the recipient client devices 720-4, 720-5, and 720-6 remaining the only device capable of decrypting the particular sender-driven group message transmitted to it by virtue of maintaining the private key corresponding to its shared public key as a secret.