Python AES String Encryption & Decryption

#=====================================#
#==============MODULES================#
#=====================================#

from Crypto.Cipher import *
from Crypto import Random
import base64

#=====================================#
#==============VARIABLES==============#
#=====================================#

menus = ["(1) AES-16 ", "(2) AES-24 ", "(3) AES-32 "]
modes = ["(1) ECB    ", "(2) CBC    ", "(3) CFB    "]
mtypes = ["(1) Encrypt", "(2) Decrypt", "(3) Exit   "]
iv_size = 16
block_size = 16

#=====================================#
#==============FUNCTIONS==============#
#=====================================#

#creates menus
def menu(parameter):
    print "     +===========+"
    print "     |    MENU   |"
    print "     |-----------|"
    for word in parameter:
        print "     |%s|" %word
        print "     |-----------|"

#define encryption algorithm
def enc(key_size, block_size, iv_size, mode):

    #get key and pad if necessary
    key = raw_input("Please enter a key: ")
    key += (key_size - len(key) % key_size) * chr(key_size - len(key) % key_size)

    #get data and pad if necessary
    data = raw_input("Please enter a string to encrypt: ")
    pad = lambda data: data + (block_size - len(data) % block_size) * chr(block_size - len(data) % block_size)

    #pad data
    data = pad(data)

    # generate random IV
    iv = Random.new().read(iv_size)

    #Est. what is needed for AES Encryption
    cipher = AES.new(key, mode, iv)

    #Combine IV and Data string and encode using base64
    output = base64.b64encode(iv + cipher.encrypt(data))

    #final encryption has IV[:16] and Data[16:]
    print "The encrypted message is: ", output

#define decryption algorithm
def dec(key_size, block_size, iv_size, mode):

    #get key & pad if necessary
    key = raw_input("Please enter a key: ")
    key += (key_size - len(key) % key_size) * chr(key_size - len(key) % key_size)

    #get data with IV & decode base64
    data = raw_input("Please enter a string to decrypt: ")
    data = base64.b64decode(data)

    #get IV
    iv = data[:iv_size]

    #strip padding
    strippad = lambda data: data[0:-ord(data[-1])]

    #define what is needed for AES
    cipher = AES.new(key, mode, iv)

    #strip off padding and decrypt data
    output = strippad(cipher.decrypt(data[iv_size:]))

    print output
#=====================================#
#===========MAIN PROGRAM==============#
#=====================================#

def main():
    menu(mtypes)

    mtypes_choice = input("Please select to encrypt, decrypt or exit (1-3): ")

    #Encryption
    if mtypes_choice == 1:
        menu(menus)
        menus_choice = input("Please select an type of AES encryption scheme(1-3): ")

        #AES-16 ENCRYPTION
        if menus_choice == 1:
            key_size = 16
            menu(modes)
            modes_choice = input("Please select a mode of encryption(1-3): ")
            if modes_choice == 1:
                mode = AES.MODE_ECB
                enc(key_size, block_size, iv_size, mode)
            elif modes_choice == 2:
                mode = AES.MODE_CBC
                enc(key_size, block_size, iv_size, mode)
            elif modes_choice == 3:
                mode = AES.MODE_CFB
                enc(key_size, block_size, iv_size, mode)

        #AES-24 ENCRYPTION
        elif menus_choice == 2:
            key_size = 24
            menu(modes)
            modes_choice = input("Please select a mode of encryption(1-3): ")
            if modes_choice == 1:
                mode = AES.MODE_ECB
                enc(key_size, block_size, iv_size, mode)
            elif modes_choice == 2:
                mode = AES.MODE_CBC
                enc(key_size, block_size, iv_size, mode)
            elif modes_choice == 3:
                mode = AES.MODE_CFB
                enc(key_size, block_size, iv_size, mode)

        #AES-32 ENCRYPTION
        elif menus_choice == 3:
            key_size = 32
            menu(modes)
            modes_choice = input("Please select a mode of encryption(1-3): ")
            if modes_choice == 1:
                mode = AES.MODE_ECB
                enc(key_size, block_size, iv_size, mode)
            elif modes_choice == 2:
                mode = AES.MODE_CBC
                enc(key_size, block_size, iv_size, mode)
            elif modes_choice == 3:
                mode = AES.MODE_CFB
                enc(key_size, block_size, iv_size, mode)


    #Decryption
    elif mtypes_choice == 2:
    menu(menus)
    menus_choice = input("Please select a type of AES encryption scheme(1-3): ")

        #AES-16 DECRYPTION
        if menus_choice == 1:
            key_size = 16
            menu(modes)
            modes_choice = input("Please select a mode of encryption(1-3): ")
            if modes_choice == 1:
                mode = AES.MODE_ECB
                dec(key_size, block_size, iv_size, mode)
            elif modes_choice == 2:
                mode = AES.MODE_CBC
                dec(key_size, block_size, iv_size, mode)
            elif modes_choice == 3:
                mode = AES.MODE_CFB
                dec(key_size, block_size, iv_size, mode)

        #AES-24 DECRYPTION
        elif menus_choice == 2:
            key_size = 24
            menu(modes)
            modes_choice = input("Please select a mode of encryption(1-3): ")
            if modes_choice == 1:
                mode = AES.MODE_ECB
                dec(key_size, block_size, iv_size, mode)
            elif modes_choice == 2:
                mode = AES.MODE_CBC
                dec(key_size, block_size, iv_size, mode)
            elif modes_choice == 3:
                mode = AES.MODE_CFB
                dec(key_size, block_size, iv_size, mode)

        #AES-32 DECRYPTION
        elif menus_choice == 3:
            key_size = 32
            menu(modes)
            modes_choice = input("Please select a mode of encryption(1-3): ")
            if modes_choice == 1:
                mode = AES.MODE_ECB
                dec(key_size, block_size, iv_size, mode)
            elif modes_choice == 2:
                mode = AES.MODE_CBC
                dec(key_size, block_size, iv_size, mode)
            elif modes_choice == 3:
                mode = AES.MODE_CFB
                dec(key_size, block_size, iv_size, mode)

    #Exit
    elif mtypes_choice == 3:
        print "Exiting Program. Goodbye."
        return