def get_public_key(cookie, tokens):
url = '<STR_LIT>'.join([<EOL>const.PASSPORT_BASE, '<STR_LIT>',<EOL>'<STR_LIT>', tokens['<STR_LIT>'],<EOL>'<STR_LIT>', util.timestamp(),<EOL>])<EOL>headers={<EOL>'<STR_LIT>': cookie.header_output(),<EOL>'<STR_LIT>': const.REFERER,<EOL>}<EOL>req = net.urlopen(url, headers=headers)<EOL>if req:<EOL><INDENT>data = req.data<EOL>return util.json_loads_single(req.data.decode())<EOL><DEDENT>return None<EOL>
获取RSA公钥, 这个用于加密用户的密码

    返回的数据如下:
    {"errno":'0',"msg":'',"pubkey":'-----BEGIN PUBLIC KEY-----\nMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDk\/ufXg3IBW8+h5i8L8NoXUzcN\nMeKrh4zEupGBkyrURIPUXKDFLWjrv4n2j3RpMZ8GQn\/ETcfoIHGBoCUKJWcfcvmi\nG+OkYeqT6zyJasF0OlKesKfz0fGogMtdCQ6Kqq7X2vrzBPL+4SNU2wgU31g\/tVZl\n3zy5qAsBFkC70vs5FQIDAQAB\n-----END PUBLIC KEY-----\n',"key":'lwCISJnvs7HRNCTxpX7vi25bV9YslF2J'}