1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
import base64
import cgi
try:
from Crypto.Cipher import AES
except:
raise Exception ("You need the pycrpyto library: http://cheeseshop.python.org/pypi/pycrypto/")
MAIL_HIDE_BASE="http://www.google.com/recaptcha/mailhide"
def asurl (email,
public_key,
private_key):
"""Wraps an email address with reCAPTCHA mailhide and
returns the url. public_key is the public key from reCAPTCHA
(in the base 64 encoded format). Private key is the AES key, and should
be 32 hex chars."""
cryptmail = _encrypt_string (email, base64.b16decode (private_key, casefold=True), '\0' * 16)
base64crypt = base64.urlsafe_b64encode (cryptmail)
return "%s/d?k=%s&c=%s" % (MAIL_HIDE_BASE, public_key, base64crypt)
def ashtml (email,
public_key,
private_key):
"""Wraps an email address with reCAPTCHA Mailhide and
returns html that displays the email"""
url = asurl (email, public_key, private_key)
(userpart, domainpart) = _doterizeemail (email)
return """%(user)s<a href='%(url)s' onclick="window.open('%(url)s', '', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,height=300'); return false;" title="Reveal this e-mail address">...</a>@%(domain)s""" % {
'user' : cgi.escape (userpart),
'domain' : cgi.escape (domainpart),
'url' : cgi.escape (url),
}
def _pad_string (str, block_size):
numpad = block_size - (len (str) % block_size)
return str + numpad * chr (numpad)
def _encrypt_string (str, aes_key, aes_iv):
if len (aes_key) != 16:
raise Exception ("expecting key of length 16")
if len (aes_iv) != 16:
raise Exception ("expecting iv of length 16")
return AES.new (aes_key, AES.MODE_CBC, aes_iv).encrypt (_pad_string (str, 16))
def _doterizeemail (email):
"""replaces part of the username with dots"""
try:
[user, domain] = email.split ('@')
except:
# handle invalid emails... sorta
user = email
domain = ""
if len(user) <= 4:
user_prefix = user[:1]
elif len(user) <= 6:
user_prefix = user[:3]
else:
user_prefix = user[:4]
return (user_prefix, domain)
|