How can you store a rsa key pair in a django model / sqlite db

Question

i am using PyCrypto within Django (Python 2.7, Django 1.5m SQLite), i would like to create a field to store an RSAkey object. How can i do this? Converting to a string and back seems pretty error prone and since random bytes are in there, i would not trust that to be a good approach. I was able to store random keys in a charfield by base-64 encoding it (like this: Random.new().read(16).encode('base64')). But a keypair? I saw in the current dev version of Django, a binary field is incorporated, but we need to stick to 1.5.

Any help would really be appreciated.

Thanks Gerd

Answer 1

you just need to store the private key, because you always can generate the public key from the private one.

>>> from Crypto.PublicKey import RSA
>>> RSAkey = RSA.generate(1024)

The public key can be exported with

>>> RSAkey.publickey().exportKey()

To save the private key you might want to convert it to a text with the exportKey() method and store it in a django-TextField:

>>> RSAkey.exportKey()
'-----BEGIN RSA PRIVATE KEY-----\nMI...-----END'

Converting the text back to a RSA key object is easy too:

>>> RSA.importKey('-----BEGIN RSA PRIVATE KEY--- ....')

gets you a RSAobj like the one I generated at first.

You might also try the "hard way" by creating your own model field class, if you intend to use the functionality in other areas as well. See https://docs.djangoproject.com/en/1.5/howto/custom-model-fields/