A device for facilitating communication between a plurality of nodes (105-1, 105-M) of a compute cluster, the device comprising a coprocessor (115-M) of a particular node (105-M) of said plurality of nodes (105-1, 105-M), the coprocessor (115-M) comprising: enqueue circuitry; said enqueue circuitry being coupled to a memory (120-M) of said particular node (105-M); said enqueue circuitry being a hardwired circuit or a persistently programmed ASIC or a persistently programmed FPGA configured to: receive , from another node (105-1) of said plurality of nodes (105-1, 105-M), an enqueue command that comprises a key with an encrypted hash code derived from a base secret, wherein: the key identifies a particular queue (300, 140-M) in said memory (120-M), the key has previously been created at said particular node (105-M) and sent from said particular node (105-M) to said other node (105-1), and the enqueue command includes a payload to be stored in the particular queue (300, 140-M); authenticate the enqueue command, comprising decrypting the encrypted hash code using said base secret stored in said coprocessor (115-M) and determining if the hash code is valid; and enqueue a queue entry (332-1, 332-2), in which said payload is stored, to the particular queue (300, 140-M) identified by the received enqueue command in response to receiving said enqueue command if the enqueue command was successfully authenticated. enqueue circuitry; said enqueue circuitry being coupled to a memory (120-M) of said particular node (105-M); said enqueue circuitry being a hardwired circuit or a persistently programmed ASIC or a persistently programmed FPGA configured to: receive , from another node (105-1) of said plurality of nodes (105-1, 105-M), an enqueue command that comprises a key with an encrypted hash code derived from a base secret, wherein: the key identifies a particular queue (300, 140-M) in said memory (120-M), the key has previously been created at said particular node (105-M) and sent from said particular node (105-M) to said other node (105-1), and the enqueue command includes a payload to be stored in the particular queue (300, 140-M); authenticate the enqueue command, comprising decrypting the encrypted hash code using said base secret stored in said coprocessor (115-M) and determining if the hash code is valid; and enqueue a queue entry (332-1, 332-2), in which said payload is stored, to the particular queue (300, 140-M) identified by the received enqueue command in response to receiving said enqueue command if the enqueue command was successfully authenticated. receive , from another node (105-1) of said plurality of nodes (105-1, 105-M), an enqueue command that comprises a key with an encrypted hash code derived from a base secret, wherein: the key identifies a particular queue (300, 140-M) in said memory (120-M), the key has previously been created at said particular node (105-M) and sent from said particular node (105-M) to said other node (105-1), and the enqueue command includes a payload to be stored in the particular queue (300, 140-M); the key identifies a particular queue (300, 140-M) in said memory (120-M), the key has previously been created at said particular node (105-M) and sent from said particular node (105-M) to said other node (105-1), and the enqueue command includes a payload to be stored in the particular queue (300, 140-M); authenticate the enqueue command, comprising decrypting the encrypted hash code using said base secret stored in said coprocessor (115-M) and determining if the hash code is valid; and enqueue a queue entry (332-1, 332-2), in which said payload is stored, to the particular queue (300, 140-M) identified by the received enqueue command in response to receiving said enqueue command if the enqueue command was successfully authenticated. <EOS>