Hash function ⇒ MAC

Hash function implies MAC.

Statement

Migrated verbatim from impagliazzos-five-worlds § Breaking up Cryptomania:

Early work of GKM+00 lays out how these different primitives relate to each other. Importantly, there is a large gap between OWF and TDP in Cryptomania: OWFs imply PRGs, PRFs, SKE, MACs, and digital signatures, but not public-key encryption. TDPs (equivalently, the existence of PKE or OT) unlock the full power of asymmetric cryptography. OT is complete for all of MPC, so Cryptomania is also the world where general secure computation is possible.

Migrated verbatim from symmetric-key-encryption § Other results:

  • CCA-secure SKE can be built from OWF: combine a CPA-secure SKE with a MAC using the encrypt-then-MAC paradigm

Notes

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

This relation is stated on 2 pages; the statements above are all of them.

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

  • DISJUNCTIVE BUNDLE: “OWFs imply PRGs, PRFs, SKE, MACs, and digital signatures” is five separate one-hypothesis reductions; this record isolates OWF MAC. Must not be stored as one hyperedge with five conclusions.
  • No citation on the clause — the canonical sources (HILL99 for OWFPRG, GGM86 for PRGPRF, Rom90/NY89 for OWFsignatures) are absent. GKM+00 is cited earlier in the paragraph but for a different claim.
  • None of the five conclusions is wikilinked here — they are bare abbreviations in prose.
  • Hypothesis OWF is only reachable via the hash-function page alias.
  • Uncited; the route actually goes through PRFs (hash-function.md:101, pseudorandom-function.md:119) and is compressed to one link here.
  • ‘OWF’ unlinked on this bullet.
  • MISSING CITATION entirely — encrypt-then-MAC is BN00 (Bellare-Namprempre); no citation and no folklore label, which the page’s own citation policy requires.
  • COMPOSITE and CONJUNCTIVE at once: OWF CPA-SKE, OWF MAC, then {CPA-SKE, MAC} CCA-SKE.
  • ‘OWF’ here has no wikilink at all (line 125 links it to hash-function; line 126 leaves it bare) — inconsistent within four lines.
  • The conclusion is a security level of SKE, not a distinct object; the graph needs security-level-qualified nodes or this edge becomes SKE SKE.
  • REPAIR PATCH: Arity sweep. Wiki L126: “CCA-secure SKE can be built from OWF: combine a CPA-secure SKE with a [[message-authentication-code|MAC]] using the encrypt-then-MAC paradigm”. The critic cites this record as a calibration example of CORRECT modelling and it is — except for the flag: the top-level edge has ONE hypothesis (OWF) and the genuine conjunction {SKE, MAC} lives in splitInto[2], where it belongs. Repair: conjunctive:false at top level. Sub-edges need their own conjunctive flag (schema defect 6.1) or this conjunction is lost on split.