CCA Security ⇒ CCA1 Security
CCA Security implies CCA1 Security.
Statement
Migrated verbatim from public-key-encryption § CCA1 Security:
CCA1 (also called the lunchtime attack) is an intermediate notion between CPA and CCA2. The adversary has access to the decryption oracle only in Phase 1, before seeing the challenge ciphertext; no decryption queries are permitted after is revealed. CCA1 is strictly weaker than CCA2 and strictly stronger than CPA.
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:
- Security-notion ordering, not an object-level reduction (‘CCA1 is strictly weaker than CCA2’).
- ‘strictly’ asserts a separation (there is a CCA1-secure scheme that is not CCA2-secure) which is uncited.
- No citation anywhere in the section.