Decrypting Epsilon Note encoded notes with python (given the password)

decrypt-en.py

#!/usr/bin/python

######################################################################
#  Decrypt an Epsilon Note encoded file given the password.
#
#  This file is in the public domain.
#
#  Dov Grobgeld <[email protected]>
#  2017-02-17 Fri
######################################################################

import sys,StringIO,base64,hashlib
from Crypto.Cipher import AES

def unpad(s):
  return s[0:-ord(s[-1])]

def filetob64(handle):
  b64 = ''
  within = False
  for line in handle:
    if '~~~~~~~~~~' in line:
      within = not within
      continue
    if within:
      b64 += line[:-1]
  return b64

def en_decrypt(handle, password):
  raw = base64.b64decode(filetob64(handle))
  enc_text,iv = raw[:-16],raw[-16:]
  key = hashlib.sha256(password).digest()[:16]
  aes = AES.new(key, AES.MODE_CBC, iv)
  return unpad(aes.decrypt(enc_text))

if len(sys.argv) > 1:
  handle = open(sys.argv[1])
  password = sys.argv[2]
else:
  # test below
  encrypted_text = '''
~~~~~~~~~~encrypted
D2gQe2He6bgKqYe4ijqoD96KORqBNbtgcAyaMYq+gROr3Qp3KG87Ti0JMdXdBh0vk4yVXlAraRGQLZnQuiCuzht03O4QBN//p4NziDyDuvM=
~~~~~~~~~~
'''
  password = 'password'
  handle = StringIO.StringIO(encrypted_text)

print en_decrypt(handle, password),

Hi, I have updated this script for python3 and aes256 (seems in 2017 epsilon used only 128bit).
https://gist.github.com/zettelding/eba76cdf702ec12cb0fb7307d149a5d9

I have also created bash-oneliner to do the same https://gist.github.com/zettelding/4f4eea0941ef94a83c0b75caab75a722

enjoy!