[oxfeed65261]

c.f. Judges 12:5-6 (https://www.bible.com/bible/114/JDG.12.5-6.NKJV):

> The Gileadites seized the fords of the Jordan before the Ephraimites arrived. And when any Ephraimite who escaped said, “Let me cross over,” the men of Gilead would say to him, “Are you an Ephraimite?” If he said, “No,” then they would say to him, “Then say, ‘Shibboleth’!” And he would say, “Sibboleth,” for he could not pronounce it right. Then they would take him and kill him at the fords of the Jordan. There fell at that time forty-two thousand Ephraimites.

[barbarbar]

Haha - This is and the comment above are awesome. But not really a backdoor.