diff --git a/twik/twik.py b/twik/twik.py
index f147bfd..ff364db 100644
--- a/twik/twik.py
+++ b/twik/twik.py
@@ -29,80 +29,87 @@ from util import Util
 import hmac
 import getpass
 import argparse
-
-def enum(**enums):
-    return type('Enum', (), enums)
-
-def injectcharacter(mhash, offset, reserved, seed, length, cstart, cnum):
-    pos0 = seed % length
-    pos = (pos0 + offset) % length
-    for i in range(0, length - reserved):
-        tmp = (pos0 + reserved + i) % length
-        char = ord(mhash[tmp])
-        if char >= ord(cstart) and char < ord(cstart) + cnum:
-            return mhash
-    head = mhash[:pos] if pos > 0 else ""
-    inject = ((seed + ord(mhash[pos])) % cnum) + ord(cstart)
-    tail = mhash[pos+1:] if (pos + 1 < len(mhash)) else mhash
-    return head + chr(inject) + tail
+import sys
 
 
-def removespecialcharacters(mhash, seed, length):
-    inputchars = list(mhash)
-    pivot = 0
-    for i in range(0, length):
-        if not inputchars[i].isdigit() and not inputchars[i].isalpha():
-            inputchars[i] = chr(((seed + pivot) % 26 + ord('A')))
-            pivot = i + 1
-    return "".join(inputchars)
-
-def converttodigits(mhash, seed, length):
-    inputchars = list(mhash)
-    pivot = 0
-    for i in range(0, length):
-        if not inputchars[i].isdigit():
-            inputchars[i] = chr(((seed + ord(inputchars[pivot])) % 10 +
-                ord('0')))
-            pivot = i + 1
-    return "".join(inputchars)
-
-def generatehash(tag, key, length, password_type):
-    digest = hmac.new(key, tag, sha1).digest()
-    mhash = digest.encode('base64')[:-2]
-
-    seed = 0
-    for i in range(0, len(mhash)):
-        seed += ord(mhash[i])
-
-    if password_type == PASSWORDTYPE.NUMERIC:
-        mhash = converttodigits(mhash, seed, length)
-    else:
-        mhash = injectcharacter(mhash, 0, 4, seed, length, '0', 10)
-        if password_type == PASSWORDTYPE.ALPHANUMERIC_AND_SPECIAL_CHARS:
-            mhash = injectcharacter(mhash, 1, 4, seed, length, '!', 15)
-        mhash = injectcharacter(mhash, 2, 4, seed, length, 'A', 26)
-        mhash = injectcharacter(mhash, 3, 4, seed, length, 'a', 26)
-
-        if password_type == PASSWORDTYPE.ALPHANUMERIC:
-            mhash = removespecialcharacters(mhash, seed, length)
-
-    return mhash[:length]
+class Twik(object):
+    def injectcharacter(self, mhash, offset, reserved, seed, length, cstart, cnum):
+        pos0 = seed % length
+        pos = (pos0 + offset) % length
+        for i in range(0, length - reserved):
+            tmp = (pos0 + reserved + i) % length
+            char = ord(mhash[tmp])
+            if char >= ord(cstart) and char < ord(cstart) + cnum:
+                return mhash
+        head = mhash[:pos] if pos > 0 else ""
+        inject = ((seed + ord(mhash[pos])) % cnum) + ord(cstart)
+        tail = mhash[pos+1:] if (pos + 1 < len(mhash)) else mhash
+        return head + chr(inject) + tail
 
 
-def getpassword(tag, private_key, master_key, length, password_type):
-    mhash = generatehash(private_key, tag, 24, 1)
-    password = generatehash(mhash, master_key, length, password_type)
-    print "Your password is %s" % password
+    def removespecialcharacters(self, mhash, seed, length):
+        inputchars = list(mhash)
+        pivot = 0
+        for i in range(0, length):
+            if not inputchars[i].isdigit() and not inputchars[i].isalpha():
+                inputchars[i] = chr(((seed + pivot) % 26 + ord('A')))
+                pivot = i + 1
+        return "".join(inputchars)
+
+    def converttodigits(self, mhash, seed, length):
+        inputchars = list(mhash)
+        pivot = 0
+        for i in range(0, length):
+            if not inputchars[i].isdigit():
+                inputchars[i] = chr(((seed + ord(inputchars[pivot])) % 10 +
+                    ord('0')))
+                pivot = i + 1
+        return "".join(inputchars)
+
+    def generatehash(self, tag, key, length, password_type):
+        digest = hmac.new(key, tag, sha1).digest()
+        mhash = digest.encode('base64')[:-2]
+
+        seed = 0
+        for i in range(0, len(mhash)):
+            seed += ord(mhash[i])
+
+        """NUMERIC"""
+        if password_type == 3:
+            mhash = self.converttodigits(mhash, seed, length)
+        else:
+            mhash = self.injectcharacter(mhash, 0, 4, seed, length, '0', 10)
+            """ALPHANUMERIC_AND_SPECIAL_CHARS"""
+            if password_type == 1:
+                mhash = self.injectcharacter(mhash, 1, 4, seed, length, '!', 15)
+            mhash = self.injectcharacter(mhash, 2, 4, seed, length, 'A', 26)
+            mhash = self.injectcharacter(mhash, 3, 4, seed, length, 'a', 26)
+
+            """ALPHANUMERIC"""
+            if password_type == 2:
+                mhash = self.removespecialcharacters(mhash, seed, length)
+
+        return mhash[:length]
+
+
+    def getpassword(self, tag, private_key, master_key, length, password_type):
+        if length > 26 or length < 4:
+            return None
+        mhash = self.generatehash(private_key, tag, 24, 1)
+        password = self.generatehash(mhash, master_key, length, password_type)
+        return password
 
 def main():
-    global PASSWORDTYPE
-    PASSWORDTYPE = enum(ALPHANUMERIC_AND_SPECIAL_CHARS=1, ALPHANUMERIC=2,
-        NUMERIC=3)
+    """
+    ALPHANUMERIC_AND_SPECIAL_CHARS=1
+    ALPHANUMERIC=2
+    NUMERIC=3
+    """
     parser = argparse.ArgumentParser()
     parser.add_argument("tag", type=str,
             help="generate password for a specified tag")
     parser.add_argument("-c", "--chars", type=int, default=-1,
-            help="length of generated password. Default: 12")
+            help="length of generated password [4-26]. Default: 12")
     parser.add_argument("-p", "--profile", type=str, default='Profile',
             help="profile to use. Default:'Profile'")
     parser.add_argument("-t", "--passwordtype", type=int, choices=[1, 2, 3],
@@ -115,13 +122,20 @@ def main():
             ''')
     args = parser.parse_args()
 
+    if args.chars > 26 or args.chars < 4:
+        print "Invalid password length [4-26]"
+        sys.exit(2)
+
     util = Util(args.tag, args.chars, args.passwordtype, args.profile)
 
     master_key = getpass.getpass(prompt='Master Key: ')
 
-    getpassword(args.tag, util.get_privatekey(), master_key,
+    twik = Twik()
+    password = twik.getpassword(args.tag, util.get_privatekey(), master_key,
             util.get_chars(), util.get_passord_type())
 
+    print "Your password is %s" % password
+
 if __name__ == "__main__":
     main()