This is a monoalphabet
C LS HKWCUG TXSD ELUYXS HDIH OMCZM OCRR VD DUZEKWHDY FTCUG L JDEK ODLP ZCWMDE C MXWD HMLH KXF OCRR VD LVRD HX VEDLP CH
Please don't spoil the puzzle by posting a solution. Post help, by all means - but be circumspect.
A solution will appear in one week.