The centuries-old technique of deciphering a secret code, also called cryptanalysis, allows people to decipher or break all sorts of secret codes for all sorts of reasons. Whether you want to intercept a secret message from an opposing team or simply find out the meaning of a coded riddle, following a few steps will help you break the secret code.
Compile all the information you know about the message starting with from whom it came and to whom the secret code was sent. On this basis, guess the most likely language (such as English or Spanish) of the secret code so you can start to decipher it.
Find out the list of most frequently occurring letters in the language you think the message was originally written in before it was coded. In English, for instance, the letter "E" is the most frequently occurring letter in text and conversation, followed by "T," "A" and so on.
Count the number of times any given symbol appears in the secret code and make a tally of each symbol. Then, replace all instances of the most frequently occurring letter with the most frequently occurring letter in the language you think the secret code was originally written in. Do the same for second, third and fourth most frequently occurring letters.
Try to find words in the secret code that are partially broken, in the sense that most of the letters are revealed by the previous steps. Alternatively, look at words that have only a few letters revealed but look as if they couldn't be anything else. Write the full word that you think is most likely for one such word. Then, look at the new letter-symbol relationship you deciphered and apply the cypher to the rest of the text to see if it makes sense.
Go back to a partially deciphered word if your application of the cypher doesn't make sense, and try to find a different word that you can make out of it that reveals new relationships between the symbols of the secret code and the letters of the language. Continue to do this until you find a configuration that successfully deciphers more and more of the secret code.