But if : w(23)-3=20→t, k(11)-3=8→h, h(8)-3=5→e, r(18)-3=15→p? No, 15→p, m(13)-3=10→k — "thepk" — no.
Given the difficulty, maybe the cipher is for the whole string: Download- shrmwtt tjyb shyqha ydklha ksha wkhrm ...
Given the pattern, this might be (A↔Z, B↔Y, etc.). Let's test first word: But if : w(23)-3=20→t
Here is a short on the topic: Title: Breaking Simple Ciphers – A Practical Approach this might be (A↔Z
"hsindgg" — no. But noticing the string ends with "wkhrm" — in ROT3 (shift +3): wkhrm becomes "thank" ? Let's check: w(23)+3=26→z? Wait, no. w+3=26 mod26=0? Let's recalc properly: w=23, +3=26, 26 mod26=0→A (but if 0=a). k=11, +3=14→n. h=8+3=11→l? r=18+3=21→v. m=13+3=16→q. "anlvq" — no.
But let’s try (or –15) sometimes used: No.