CDH ⇒ DDH
Statement
Migrated verbatim from decisional-diffie-hellman § Decisional Diffie-Hellman:
The Decisional Diffie-Hellman (DDH) assumption is a central assumption in cryptography, and one of the first used to construct key exchange DH76. It is implied by the CDH assumption. In other words, an adversary which can solve the CDH problem can also solve DDH in the same group.
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:
- SUSPECTED MATHEMATICAL ERROR: It is implied by the CDH assumption is backwards — DDH hardness implies CDH hardness, not the reverse. The very next sentence (an adversary solving CDH also solves DDH) states the correct relation and contradicts it.
- Uncited.
- computational-diffie-hellman.md line 12 contains the mirrored version of the same confusion.