security flaw?

[sunneydev]

do sqids protect from someone just collecting lots of different ids and just combining the characters from there to then match your "unique character set" ?

[4kimov]

Not sure what unique character set is referring to, but security and sqids do not go together in any combination, so the answer is probably no.

Edit: If you're referring to someone recreating the alphabet by simply observing IDs, yes it's possible. But the characters in the alphabet are not as important as the order of those characters.