Pirouette: Query Efficient Single-Server PIR#

Authors: Jiayi Kang (COSIC, KU Leuven), Leonard Schild (COSIC, KU Leuven)

• Why: The single biggest obstacle to practical PIR has always been the cost of the client's query (uploading a padded database-sized vector). Query-efficient single-server PIR is the enabler behind private password-breach checking, private contact discovery, and private key-value lookups — identity-adjacent infrastructure use cases you'd otherwise have to trust a third party for.
• What: Apparently a single-server PIR scheme whose contribution is driving client query size down while keeping server computation tolerable (title/author line only — no abstract in program).
• How: Not described in the program; COSIC's recent line of work has pushed homomorphic-encryption-based PIR with preprocessing and compact queries, so expect that machinery with a new efficiency point on the upload/compute curve.
• Where applicable: Any "server holds a list, client learns only its own entry" service — credential-breach alerting, presence lookup, blocklist checks. General technique, no trusted third party required.