ciphertext="AGHFXK{5ai5b1cee10z}"As the challenge named as "Shifter salad", I think it would be a " vignere cipher"  as it contains salad. After using *vignere cipher*,I used AFFCTF as key. It prints first 6 letters as ABCDEF. May be this will be a hint. So, I used ABCDEFGHIJKLM. until I get the flag. Then the flag is finallyas AFFCTF{5ub5t1tut10n}.Then, wrap it *AFFCTF{5ub5t1tut10n}*