Vigenère cipher python functions

vigenere.py

from string import ascii_lowercase

def buildmap():
	table = {}
	for x in range(0,len(ascii_lowercase)):
		row = {}
		c = 0
		for y in range(0,len(ascii_lowercase)):
			row[ascii_lowercase[y]] = ascii_lowercase[x+y+c]
			if x+y > 24:
				c = -26
			
		
		table[ascii_lowercase[x]] = row
		
	return table
			

def build_mask(password,lenx):
	mask = ""
	x = 0
	c = 0
	while x < lenx:
		mask = mask + password[c]
		x = x + 1
		c = c + 1
		if c >= len(password):
			c = 0	
	return mask


def crypt(clear,password):
	mask = build_mask(password,len(clear))
	out = ""
	low_clear = clear.lower()
	table = buildmap()
	for x in range(0,len(clear)):
		out = out  + table[mask[x]][low_clear[x]]
	
	return out

def decrypt(hashed,password):
	mask = build_mask(password,len(hashed))
	out = ""
	low_hashed = hashed.lower()
	table = buildmap()
	for x in range(0,len(low_hashed)):
		for c in table[mask[x]]:
			if table[mask[x]][c] == low_hashed[x]:
				out = out + c
	return out