Data communication between a group of users

A computer-implemented method, comprising:

• receiving, by a device of a user in a group of users in a communication system, a quorum portion of a group signing key;
• communicating, by the device, a group data output to devices of other users in the group of users;
• generating, by the device, a portion of a group digital signature by digitally signing the group data output based at least on the received quorum portion of the group signing key;
• encrypting, by the device, the generated portion of a group digital signature using a public group encryption key;
• and
• transmitting, by the device, the encrypted portion of the group digital signature to a server in the communication system, wherein the server reconstructs a group digital signature from a predetermined minimum number of encrypted portions of the group digital signature generated by respective devices of the group of users.

A system for implementing communication of data between a group of users in a communication system, the system comprising a computer processor configured to perform a method of:

• generating, by a server of the communication system, a plurality of quorum portions of a group signing key;
• providing, by the server, at least one of said plurality of quorum portions of the group signing key to each of a plurality of devices of the group of users, to configure each device to become operable to generate an encrypted portion of a group digital signature using a corresponding quorum portion of the group signing key;
• receiving, by the server, a predetermined minimum number of encrypted portions of the group digital signature, each generated by a respective device of the group of users;
• and
• combining, by the server, the predetermined minimum number of encrypted portions of the group digital signature to construct an encrypted group digital signature.

A non-transitory computer-readable medium comprising computer-executable instructions that when executed on a computing device perform a method for implementing communication of data between a group of users in a communication system, the method comprising:

• generating, by a server of the communication system, a plurality of quorum portions of a group signing key;
• providing, by the server, at least one of said plurality of quorum portions of the group signing key to each of a plurality of devices of the group of users, to configure each device to become operable to generate an encrypted portion of a group digital signature using a corresponding quorum portion of the group signing key;
• receiving, by the server, a predetermined minimum number of encrypted portions of the group digital signature, each generated by a respective device of the group of users;
• and
• combining, by the server, the predetermined minimum number of encrypted portions of the group digital signature to construct an encrypted group digital signature.