I would like to encrypt a secret text by public-key and decrypt it by private-key in Python.
I can achieve that with the openssl command:
echo "secrettext/2011/09/14 22:57:23" | openssl rsautl -encrypt -pubin -inkey public.pem | base64 data.cry
base64 -D data.cry | openssl rsautl -decrypt -inkey private.pem
How would one implement that in Python?
#!/usr/bin/env python
import fileinput
from M2Crypto import RSA
rsa = RSA.load_pub_key("public.pem")
ctxt = rsa.public_encrypt(fileinput.input().read(), RSA.pkcs1_oaep_padding)
print ctxt.encode('base64')
#!/usr/bin/env python
import fileinput
from M2Crypto import RSA
priv = RSA.load_key("private.pem")
ctxt = fileinput.input().read().decode('base64')
print priv.private_decrypt(ctxt, RSA.pkcs1_oaep_padding)
See also How to encrypt a string using the key and What is the best way to encode string by public-key in python.
Probably the easiest way to get exactly the same behaviour would be using pyOpenSSL - it's a thin Python wrapper for OpenSSL itself.
The m2crypto module(s) expose much of OpenSSL's functionality to Python, including public/private encryption, decryption, and signing.
Most Linux distribution provide the m2crypto module as a native package.
