2
APL, 39 bytes, cracked by Mauris
"Helo, Wrd!"[0,1,2,2,3,4,5,6,3,7,2,8,9]
Efficiency is everything.
This works in the ngn-apl online interpreter (permalink).
I was hoping the double quotes, commas and zero-based indexing would be enough to cause some confusion, as they're not normally used in...