USENIX Security '22 - Orca: Blocklisting in Sender-Anonymous Messaging

USENIX Security '22 - Orca: Blocklisting in Sender-Anonymous Messaging

Nirvan Tyagi and Julia Len, Cornell University; Ian Miers, University of Maryland; Thomas Ristenpart, Cornell Tech

Sender-anonymous end-to-end encrypted messaging allows sending messages to a recipient without revealing the sender's identity to the messaging platform. Signal recently introduced a sender anonymity feature that includes an abuse mitigation mechanism meant to allow the platform to block malicious senders on behalf of a recipient.We explore the tension between sender anonymity and abuse mitigation. …

anonymous blocklisting messaging orca security usenix