import hashlib f = open('input.txt', 'r') dat = f.read() f.close() out = open('hashed.txt', 'w') letters = set(list(dat)) hashDict = {} backDict = {} for c in letters : hashDict[c] = hashlib.md5(str(c)).hexdigest() backDict[hashDict[c]] = c res = '' for c in dat : res += hashDict[c] + '\n' out.write(res) out.close() checkWork = '' for tmp in res.split('\n') : if tmp == '' : continue checkWork += backDict[tmp] print checkWork