No reduction from Binding + Hiding to COM

A reduction of class unstated from Binding together with Hiding to COM would imply a contradiction.

Statement

Migrated verbatim from commitment-scheme § Properties / Binding:

Note: Perfect (simultaneously statistically hiding and statistically binding) commitment schemes are impossible by a simple entropy argument. The four regimes are: (1) perfectly binding / computationally hiding, (2) computationally binding / statistically hiding, (3) computationally binding / computationally hiding, and (4) perfectly binding / perfectly hiding — which is impossible.

Notes

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

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

• NO CITATION and no folklore marker. CLAUDE.md requires either a citation or an explicit ’— standard’ / ’— folklore’ label; this has neither, it just asserts ‘by a simple entropy argument’.
• A genuine unconditional two-hypothesis impossibility ({statistically hiding, statistically binding} ⇒ contradiction) — a good barrier-page candidate, and one of the few on the wiki with an actual proof idea attached.
• The four-regime enumeration that follows is useful taxonomy, but regime (4) ‘perfectly binding / perfectly hiding — which is impossible’ restates the first sentence, an anti-pattern.