actor "Data Broker" as broker
actor "Data Owner 1" as owner1
actor "Data Owner 2" as owner2
actor "Data Owner 3" as owner3
owner1 -> broker: Send summary statistics
owner2 -> broker: Send summary statistics
owner3 -> broker: Send summary statistics
broker --> owner1: Send pooled statistics
broker --> owner2: Send pooled statistics
broker --> owner3: Send pooled statistics
owner1 -> broker: Encrypt and share ciphertext
owner2 -> broker: Encrypt and share ciphertext
owner3 -> broker: Encrypt and share ciphertext
broker -> owner1: Share concatenated ciphertext
broker -> owner2: Share concatenated ciphertext
broker -> owner3: Share concatenated ciphertext