Add problem statement

src/Python/Problem059.py

@@ -15,7 +15,32 @@ from utils import timeit
 @timeit("Problem 59")
 def compute():
     """
-    # Statement
+    Each character on a computer is assigned a unique code and the preferred 
+    standard is ASCII (American Standard Code for Information Interchange). 
+    For example, uppercase A = 65, asterisk (*) = 42, and lowercase k = 107.
+
+    A modern encryption method is to take a text file, convert the bytes to 
+    ASCII, then XOR each byte with a given value, taken from a secret key. 
+    The advantage with the XOR function is that using the same encryption key 
+    on the cipher text, restores the plain text; for example, 65 XOR 42 = 107, 
+    then 107 XOR 42 = 65.
+
+    For unbreakable encryption, the key is the same length as the plain text 
+    message, and the key is made up of random bytes. The user would keep the 
+    encrypted message and the encryption key in different locations, and 
+    without both "halves", it is impossible to decrypt the message.
+
+    Unfortunately, this method is impractical for most users, so the modified 
+    method is to use a password as a key. If the password is shorter than the 
+    message, which is likely, the key is repeated cyclically throughout the 
+    message. The balance for this method is using a sufficiently long password 
+    key for security, but short enough to be memorable.
+
+    Your task has been made easy, as the encryption key consists of three 
+    lower case characters. Using p059_cipher.txt, a file containing the 
+    encrypted ASCII codes, and the knowledge that the plain text must contain 
+    common English words, decrypt the message and find the sum of the ASCII 
+    values in the original text.
     """
 
     # Your code goes here