Synnefo

from django.conf import settings

from synnefo.userdata import asn1

from Crypto.PublicKey import RSA

from Crypto.Util.number import inverse

import binascii

import base64

SSH_KEY_LENGTH = getattr(settings, 'UI_SSH_KEY_LENGTH', 1024)

def generate_key_pair(request):

    """

    Response to generate private/public RSA key pair

    """

    key = RSA.generate(SSH_KEY_LENGTH)

    # generate private content in PEM format

    seq = asn1.DerSequence()

    seq[:] = [ 0, key.n, key.e, key.d, key.p, key.q, key.d % (key.p-1), key.d % (key.q-1), inverse(key.q, key.p)]

    pem = asn1.b("-----BEGIN PRIVATE KEY-----\n")

    binaryKey = seq.encode()

    chunks = [ binascii.b2a_base64(binaryKey[i:i+48]) for i in range(0, len(binaryKey), 48) ]

    pem += asn1.b('').join(chunks)

    pem += asn1.b("-----END PRIVATE KEY-----\n")

    # generate public content

    seq = asn1.DerSequence()

    ssh_rsa = '00000007' + base64.b16encode('ssh_rsa')

    exponent = '%x' % (key.e, )

    if len(exponent) % 2:

        exponent = '0' + exponent

    ssh_rsa += '%08x' % (len(exponent) / 2, )

    ssh_rsa += exponent

    modulus = '%x' % (key.n, )

    if len(modulus) % 2:

        modulus = '0' + modulus

    if modulus[0] in '89abcdef':

        modulus = '00' + modulus

    ssh_rsa += '%08x' % (len(modulus) / 2, )

    ssh_rsa += modulus

    public = 'ssh-rsa %s' % (base64.b64encode(base64.b16decode(ssh_rsa.upper())),)

    print pem

    print

    print

    print public

    data = {'private': pem, 'public': public}

    return http.HttpResponse(json.dumps(data), mimetype="application/json")