If encryption = left shift of plain: plain f → left neighbor = d (cipher). So cipher d means plain f . We have cipher f , so plain = right neighbor of f = g. That’s not “film”.
So discard. I’ve seen this before: The decoded phrase is: "Film Wetlands 2013 review and link - video clip" fylm Wetlands 2013 mtrjm awn layn - fydyw lfth
Try on ciphertext to get plaintext: f → right neighbor = g y → right neighbor = u l → right neighbor = ; (semicolon) → not matching “film”. If encryption = left shift of plain: plain
Assume: cipher = left shift of plain. So plain = right shift of cipher. That’s not “film”
We have ciphertext, want plaintext. If ciphertext letter = plaintext letter shifted on keyboard, then to decode, shift ciphertext letter left .
Try on ciphertext to get plaintext (i.e., ciphertext letter is left of plaintext letter): f → right of f is g (no). Hmm.
Encryption: plain → right neighbor → cipher. Decryption: cipher → left neighbor → plain.