Three may keep counsel, if two be away.

Meaning: Secrets survive only when fewer mouths know them; a third person inevitably spreads what two shared.

Origin: This is the older and gentler English form: three people can keep a secret only if two of them are absent. Benjamin Franklin, who liked to sharpen proverbs he found in earlier collections, darkened it in Poor Richard's Almanack (1735): "Three may keep a secret, if two of them are dead."