IND-sID-CPA Security (Selective) ⇒ IND-ID-CPA Security

IND-sID-CPA Security (Selective) implies IND-ID-CPA Security.

Statement

Migrated verbatim from identity-based-encryption:

is negligible. Any IND-ID-CPA-secure scheme is also IND-sID-CPA-secure; the converse requires a complexity-leveraging argument that incurs a polynomial security loss in .

Notes

source: folklore: the claim carried no citation on the page it was migrated from, and none was invented.

class: unstated: no citing page says which notion of reduction is meant. Recording a class the wiki does not state would add a claim.

Recorded during migration and not fixed — these are claims about the source text, not changes to it:

  • SUSPECT MATH: ‘the converse requires a complexity-leveraging argument that incurs a polynomial security loss in |I|‘. Complexity leveraging loses a factor of |I|, which is exponential in the identity length - describing it as a ‘polynomial security loss’ is at best misleading and reads as an error. Report only; do not fix.
  • Complexity leveraging also requires sub-exponential hardness, which is not stated as a hypothesis.
  • No citation.