Convert binary data to hex representation and back

hextostr.py

import string

def BinToHex(a):
	return "".join(["%02x" % ord(ch) for ch in a])

def HexToBin(a):
	out = []
	for i in range(0, len(a), 2):
		twoChrs = a[i:i+2]
		v = string.atoi(twoChrs, 16)
		out.append(chr(v))
	return "".join(out)