picoCTF 2014: Substitution (Cryptography) Write-up

Solve:

There's an authorization code for some Thyrin Labs information here, along with someone's favorite song. But it's been encrypted! Find the authorization code.
encrypted.txt

encrypted.txt:

kve fqkvsnojfkosd rspe ol hebnebfnep

o deten kvsquvk vaedfl elledkofc
kveane rnqpe fdp qdlbefxfhca bcfod
hqk mfahe kveate f ucommen sz bskedkofc
oz fccoep ks ma tolosd fdp hnfod

o xdsg kvfk asqn bsgenl sz nekedkosd
fne fl gek fl f gfnkvsul hfrxlope
hqk kvorx fl asq fne bfa fkkedkosd
ma gsnpl fne f mfkken sz bnope  
...[snip]...

Hint:

You may want to look at what the relative frequencies of letters in english text are.

Solution:
          When I read a hint and solve, I see a text so interest, frequencies, substitution, That's as may be means substitution cipher. I think I should find online tool to decode some messages in encrypted.txt and I found http://rumkin.com/tools/cipher/cryptogram-solver.php and select some messages (o xdsg kvfk asqn bsgenl sz nekedkosd) input and click "Solve The Cryptogram"

          When I have the results, I select some result to search in google.com and found song lyrics of "The Lion King - Be Prepared", I back to read this problem are favorite song and I think I got a flag. :)

Flag: Be Prepared