Substitution cipher fun...

Here is one of the crypto puzzles I got from my friend Cactus a while back. This was fun to play with and resolve. It looks really hard at first, but if you know how substitution ciphers work, learn a couple of tricks, and have some tool that helps you out, then it is not that hard... It is definitely worth trying... So, here it is...

Below is a substitution cipher text of an English plain text in which all white spaces and punctuation have been removed prior to encoding.

FCHIMUSZHIKNIFMFKFMYQWMSCHTMIRWMSCHTFCRFCRINHHQMQKIHAYTURQBCKQVTHVIYABHRTIMFNRIMWRZZBWYQIMIFIYAIKNIFMFKFMQPHJHTBSZRMQFHDFWCRTRWFHTAYTRVMAAHTHQFWMSCHTFHDFWCRTRWFHTMFVMAAHTIATYUFCHWRHIRTWMSCHTMQFCRFFCHWMSCHTRZSCRNHFMIQYFIMUSZBFCHRZSCRNHFICMAFHVMFMIWYUSZHFHZBEKUNZHVFCHIMUSZHIKNIFMFKFMYQWMSCHTYAAHTIJHTBZMFFZHWYUUKQMWRFMYQIHWKTMFBRQVMIXKMFHHRIBFYNTHRLMFWRQNHNTYLHQHJHQNBCRQVHISHWMRZZBRIFCHUHIIRPHINHWYUHUYTHFCRQIHJHTRZCKQVTHVWMSCHTFHDFWCRTRWFHTIRWTBSFRQRZBIFCRIFYAMQVFCHLHBFCRFORIKIHVFYHQWTBSFFCHUHIIRPHOCMWCUHRQIAMQVMQPFCHURSSMQPAYTHRWCWCRTRWFHTHJHQFCYKPCFCHQKUNHTYALHBIMIRTHRZZBNMPQKUNHTFCHTHMIRZYFYATHVKQVRQWBRQVYFCHTIFRFMIFMWRZSTYSHTFMHIYAHQPZMICFHDFFCRFURLHMFXKMFHHRIBFYVHFHTUMQHRTHRIYQRNZBPYYVLHBFCHAMTIFIFHSMIFYWRZWKZRFHFCHATHXKHQWBVMIFTMNKFMYQYAFCHZHFFHTIMQFCHWMSCHTFHDFFCMIWYQIMIFIYAWYKQFMQPCYOURQBFMUHIHRWCZHFFHTRSSHRTIQRFKTRZHQPZMICFHDFCRIRJHTBVMIFMQWFVMIFTMNKFMYQFCRFWRQNHKIHVFYCHZSWTRWLWYVHIFCMIVMIFTMNKFMYQWRQNHHRIMZBAYKQVMQMQFHTQHFICYTFSMHWHIYAFHDFYAFHQQHHVUYTHHDSHTFMIHFYWTRWLMAFCHYTMPMQRZSKQWFKRFMYQHDMIFIMQFCHUHIIRPHFCHQMFMISYIIMNZHFYKIHATHXKHQFFOYFCTHHRQVAYKTZHFFHTOYTVIFYPKHIIIYUHYAFCHOYTVIFCHQKIMQPFCMIMQAYTURFMYQSTYWHHVOMFCPKHIIMQPZYQPHTOYTVIKIKRZZBCYOHJHTSKQWFKRFMYQMQWMSCHTFHDFMITHUYJHVRQVFCHWMSCHTFHDFMISKFMQFYNZYWLIYTMQFCHUYIFVMAAMWKZFWRIHRIYQHNZYWLYAWCRTRWFHTIOMFCYKFRQBSKQWFKRFMYQMQFCHIHWRIHIURQBYFCHTWCRTRWFHTMIFMWIYAFCHHQPZMICZRQPKRPHWRQNHKFMZMGHVIKWCRIUYIFATHXKHQFVMPTRSCIYTFTMPTRSCIUYIFWYUUYQVYKNZHIYTUYIFATHXKHQFAMQRZZHFFHTI

You must find the key that was used to encode the plain text. Fun, isn't it? :)