simple encrypt/decrypt lib in python with private key

http://www.dlitz.net/software/pycrypto/ should do what you want.

Taken from their docs page.

>>> from Crypto.Cipher import DES
>>> obj=DES.new('abcdefgh', DES.MODE_ECB)
>>> plain="Guido van Rossum is a space alien."
>>> len(plain)
34
>>> obj.encrypt(plain)
Traceback (innermost last):
  File "<stdin>", line 1, in ?
ValueError: Strings for DES must be a multiple of 8 in length
>>> ciph=obj.encrypt(plain+'XXXXXX')
>>> ciph
'\021,\343Nq\214DY\337T\342pA\372\255\311s\210\363,\300j\330\250\312\347\342I\3215w\03561\303dgb/\006'
>>> obj.decrypt(ciph)
'Guido van Rossum is a space alien.XXXXXX'

pyDES is a DES and Triple-DES implementation completely written in python.

Here's a simple and portable example that should be secure enough for basic string encryption needs. Just put the pyDES module in the same folder as your program and try it out:

Sender's computer

>>> from pyDES import *  # pyDes if installed from pip
>>> ciphertext = triple_des('a 16 or 24 byte password').encrypt("secret message", padmode=2)  #plain-text usually needs padding, but padmode = 2 handles that automatically
>>> ciphertext
')\xd8\xbfFn#EY\xcbiH\xfa\x18\xb4\xf7\xa2'  #gibberish

Recipient's computer

>>> from pyDES import *
>>> plain_text = triple_des('a 16 or 24 byte password').decrypt(')\xd8\xbfFn#EY\xcbiH\xfa\x18\xb4\xf7\xa2', padmode=2)
>>> plain_text
"secret message"

---

You might get an error in Python3 from code of Recipient's computer

ValueError: pyDes can only work with encoded strings, not Unicode.

from pyDes import *

a = b')\xd8\xbfFn#EY\xcbiH\xfa\x18\xb4\xf7\xa2'
plain_text = triple_des('a 16 or 24 byte password').decrypt(a, padmode=2)
print(plain_text)

Just Add b at the beginning of the encrypted text. For clearer code, assign it to a new variable (in this case, it's a, and decrypt a in a normal way).

for python 2, you should use keyczar http://www.keyczar.org/

for python 3, until keyczar is available, i have written simple-crypt http://pypi.python.org/pypi/simple-crypt

i'm answering this two years late as things have changed since the question was asked.

note that the previous answers to this question use weak ciphers (by today's standards) and don't have any key strengthening. the two recommendations here are likely more secure.