IND-sID-CPA Security (Selective) ⇒ HIBE

Standard model · GKR25, DG17b

Statement

From any IND-sID-CPA-secure IBE there is an adaptively secure (IND-HIBE-CPA) HIBE in the standard model — GKR25. A selectively secure HIBE supporting arbitrarily many delegations was known earlier from the same hypothesis — DG17b.

Notes

• The HIBE supports identities of unbounded length and an unbounded number of delegation levels, and the construction extends to an adaptively secure anonymous HIBE under CDH or LWE — GKR25.