oblivious-prf · research · also OPRF

Oblivious pseudorandom function

An oblivious pseudorandom function protocol lets a client obtain a keyed function's output while hiding the input from the server and the server key from the client.

Related Observatory article: Oblivious pseudorandom function on hesela.com

RFC 9497 specifies prime-order-group OPRF variants; verifiable OPRFs additionally bind evaluations to a known public key. It is an Informational IRTF publication, not an IETF standard. This primitive does not by itself provide application authentication or query quotas. [1] Storage use must document the surrounding trust model. [2]

Relations

related

convergent-encryption, deduplication, cryptographic-hash

Citations

1. RFC 9497: Oblivious Pseudorandom Functions (OPRFs) Using Prime-Order Groups (2023), sections 1 and 7. Informational IRTF publication. (accessed 2026-10-18)
2. Hesela: Encrypted deduplication: who can test a file guess? (accessed 2026-10-18)

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