# Source code for onelogin.saml2.utils

    # -*- coding: utf-8 -*-

    """ OneLogin_Saml2_Utils class

    MIT License

    Auxiliary class of Python Toolkit.

    """

    import base64
    from copy import deepcopy
    from datetime import datetime
    import calendar
    from hashlib import sha1, sha256, sha384, sha512
    from isodate import parse_duration as duration_parser
    from lxml import etree
    from os.path import basename, dirname, join
    import re
    from sys import stderr
    from tempfile import NamedTemporaryFile
    from textwrap import wrap
    from urllib import quote_plus
    from urlparse import urlsplit, urlunsplit
    from uuid import uuid4
    from xml.dom.minidom import Document, Element
    from defusedxml.minidom import parseString
    from functools import wraps

    import zlib

    import dm.xmlsec.binding as xmlsec
    from dm.xmlsec.binding.tmpl import EncData, Signature

    from onelogin.saml2.constants import OneLogin_Saml2_Constants
    from onelogin.saml2.errors import OneLogin_Saml2_Error, OneLogin_Saml2_ValidationError
    from onelogin.saml2.xmlparser import tostring, fromstring

    if not globals().get('xmlsec_setup', False):
        xmlsec.initialize()
        globals()['xmlsec_setup'] = True

    def return_false_on_exception(func):
        """
        Decorator. When applied to a function, it will, by default, suppress any exceptions
        raised by that function and return False. It may be overridden by passing a
        "raise_exceptions" keyword argument when calling the wrapped function.
        """
        @wraps(func)
        def exceptfalse(*args, **kwargs):
            if not kwargs.pop('raise_exceptions', False):
                try:
                    return func(*args, **kwargs)
                except Exception:
                    return False
            else:
                return func(*args, **kwargs)
        return exceptfalse

    def print_xmlsec_errors(filename, line, func, error_object, error_subject, reason, msg):
        """
        Auxiliary method. It overrides the default xmlsec debug message.
        """

        info = []
        if error_object != "unknown":
            info.append("obj=" + error_object)
        if error_subject != "unknown":
            info.append("subject=" + error_subject)
        if msg.strip():
            info.append("msg=" + msg)
        if reason != 1:
            info.append("errno=%d" % reason)
        if info:
            print("%s:%d(%s)" % (filename, line, func), " ".join(info))

    class OneLogin_Saml2_Utils(object):
        """

        Auxiliary class that contains several utility methods to parse time,
        urls, add sign, encrypt, decrypt, sign validation, handle xml ...

        """

        RESPONSE_SIGNATURE_XPATH = '/samlp:Response/ds:Signature'
        ASSERTION_SIGNATURE_XPATH = '/samlp:Response/saml:Assertion/ds:Signature'

        TIME_FORMAT = "%Y-%m-%dT%H:%M:%SZ"
        TIME_FORMAT_2 = "%Y-%m-%dT%H:%M:%S.%fZ"
        TIME_FORMAT_WITH_FRAGMENT = re.compile(r'^(\d{4,4}-\d{2,2}-\d{2,2}T\d{2,2}:\d{2,2}:\d{2,2})(\.\d*)?Z?$')

        @staticmethod
        def decode_base64_and_inflate(value):
            """
            base64 decodes and then inflates according to RFC1951
            :param value: a deflated and encoded string
            :type value: string
            :returns: the string after decoding and inflating
            :rtype: string
            """
            decoded = base64.b64decode(value)
            # We try to inflate
            try:
                result = zlib.decompress(decoded, -15)
            except Exception:
                result = decoded

            return result.decode('utf-8')

        @staticmethod
        def deflate_and_base64_encode(value):
            """
            Deflates and then base64 encodes a string
            :param value: The string to deflate and encode
            :type value: string
            :returns: The deflated and encoded string
            :rtype: string
            """
            return base64.b64encode(zlib.compress(value.encode('utf-8'))[2:-4])

        @staticmethod
        def validate_xml(xml, schema, debug=False):
            """
            Validates a xml against a schema
            :param xml: The xml that will be validated
            :type: string|DomDocument
            :param schema: The schema
            :type: string
            :param debug: If debug is active, the parse-errors will be showed
            :type: bool
            :returns: Error code or the DomDocument of the xml
            :rtype: string
            """
            assert isinstance(xml, basestring) or isinstance(xml, Document) or isinstance(xml, etree._Element)
            assert isinstance(schema, basestring)

            if isinstance(xml, Document):
                xml = xml.toxml()
            elif isinstance(xml, etree._Element):
                xml = tostring(xml, encoding='unicode')

            # Switch to lxml for schema validation
            try:
                dom = fromstring(xml.encode('utf-8'), forbid_dtd=True)
            except Exception:
                return 'unloaded_xml'

            schema_file = join(dirname(__file__), 'schemas', schema)
            f_schema = open(schema_file, 'r')
            schema_doc = etree.parse(f_schema)
            f_schema.close()
            xmlschema = etree.XMLSchema(schema_doc)

            if not xmlschema.validate(dom):
                if debug:
                    stderr.write('Errors validating the metadata')
                    stderr.write(':\n\n')
                    for error in xmlschema.error_log:
                        stderr.write('%s\n' % error.message)

                return 'invalid_xml'

            return parseString(tostring(dom, encoding='unicode').encode('utf-8'), forbid_dtd=True, forbid_entities=True, forbid_external=True)

        @staticmethod
        def element_text(node):
            # Double check, the LXML Parser already removes comments
            etree.strip_tags(node, etree.Comment)
            return node.text

        @staticmethod
        def format_cert(cert, heads=True):
            """
            Returns a x509 cert (adding header & footer if required).

            :param cert: A x509 unformatted cert
            :type: string

            :param heads: True if we want to include head and footer
            :type: boolean

            :returns: Formatted cert
            :rtype: string
            """
            x509_cert = cert.replace('\x0D', '')
            x509_cert = x509_cert.replace('\r', '')
            x509_cert = x509_cert.replace('\n', '')
            if len(x509_cert) > 0:
                x509_cert = x509_cert.replace('-----BEGIN CERTIFICATE-----', '')
                x509_cert = x509_cert.replace('-----END CERTIFICATE-----', '')
                x509_cert = x509_cert.replace(' ', '')

                if heads:
                    x509_cert = "-----BEGIN CERTIFICATE-----\n" + "\n".join(wrap(x509_cert, 64)) + "\n-----END CERTIFICATE-----\n"

            return x509_cert

        @staticmethod
        def format_private_key(key, heads=True):
            """
            Returns a private key (adding header & footer if required).

            :param key A private key
            :type: string

            :param heads: True if we want to include head and footer
            :type: boolean

            :returns: Formatted private key
            :rtype: string
            """
            private_key = key.replace('\x0D', '')
            private_key = private_key.replace('\r', '')
            private_key = private_key.replace('\n', '')
            if len(private_key) > 0:
                if private_key.find('-----BEGIN PRIVATE KEY-----') != -1:
                    private_key = private_key.replace('-----BEGIN PRIVATE KEY-----', '')
                    private_key = private_key.replace('-----END PRIVATE KEY-----', '')
                    private_key = private_key.replace(' ', '')
                    if heads:
                        private_key = "-----BEGIN PRIVATE KEY-----\n" + "\n".join(wrap(private_key, 64)) + "\n-----END PRIVATE KEY-----\n"
                else:
                    private_key = private_key.replace('-----BEGIN RSA PRIVATE KEY-----', '')
                    private_key = private_key.replace('-----END RSA PRIVATE KEY-----', '')
                    private_key = private_key.replace(' ', '')
                    if heads:
                        private_key = "-----BEGIN RSA PRIVATE KEY-----\n" + "\n".join(wrap(private_key, 64)) + "\n-----END RSA PRIVATE KEY-----\n"
            return private_key

        @staticmethod
        def redirect(url, parameters={}, request_data={}):
            """
            Executes a redirection to the provided url (or return the target url).

            :param url: The target url
            :type: string

            :param parameters: Extra parameters to be passed as part of the url
            :type: dict

            :param request_data: The request as a dict
            :type: dict

            :returns: Url
            :rtype: string
            """
            assert isinstance(url, basestring)
            assert isinstance(parameters, dict)

            if url.startswith('/'):
                url = '%s%s' % (OneLogin_Saml2_Utils.get_self_url_host(request_data), url)

            # Verify that the URL is to a http or https site.
            if re.search('^https?://', url) is None:
                raise OneLogin_Saml2_Error(
                    'Redirect to invalid URL: ' + url,
                    OneLogin_Saml2_Error.REDIRECT_INVALID_URL
                )

            # Add encoded parameters
            if url.find('?') < 0:
                param_prefix = '?'
            else:
                param_prefix = '&'

            for name, value in parameters.items():

                if value is None:
                    param = quote_plus(name)
                elif isinstance(value, list):
                    param = ''
                    for val in value:
                        param += quote_plus(name) + '[]=' + quote_plus(val) + '&'
                    if len(param) > 0:
                        param = param[0:-1]
                else:
                    param = quote_plus(name) + '=' + quote_plus(value)

                if param:
                    url += param_prefix + param
                    param_prefix = '&'

            return url

        @staticmethod
        def get_self_url_host(request_data):
            """
            Returns the protocol + the current host + the port (if different than
            common ports).

            :param request_data: The request as a dict
            :type: dict

            :return: Url
            :rtype: string
            """
            current_host = OneLogin_Saml2_Utils.get_self_host(request_data)
            port = ''
            if OneLogin_Saml2_Utils.is_https(request_data):
                protocol = 'https'
            else:
                protocol = 'http'

            if 'server_port' in request_data and request_data['server_port'] is not None:
                port_number = str(request_data['server_port'])
                port = ':' + port_number

                if protocol == 'http' and port_number == '80':
                    port = ''
                elif protocol == 'https' and port_number == '443':
                    port = ''

            return '%s://%s%s' % (protocol, current_host, port)

        @staticmethod
        def get_self_host(request_data):
            """
            Returns the current host.

            :param request_data: The request as a dict
            :type: dict

            :return: The current host
            :rtype: string
            """
            if 'http_host' in request_data:
                current_host = request_data['http_host']
            elif 'server_name' in request_data:
                current_host = request_data['server_name']
            else:
                raise Exception('No hostname defined')

            if ':' in current_host:
                current_host_data = current_host.split(':')
                possible_port = current_host_data[-1]
                try:
                    possible_port = float(possible_port)
                    current_host = current_host_data[0]
                except ValueError:
                    current_host = ':'.join(current_host_data)

            return current_host

        @staticmethod
        def is_https(request_data):
            """
            Checks if https or http.

            :param request_data: The request as a dict
            :type: dict

            :return: False if https is not active
            :rtype: boolean
            """
            is_https = 'https' in request_data and request_data['https'] != 'off'
            is_https = is_https or ('server_port' in request_data and str(request_data['server_port']) == '443')
            return is_https

        @staticmethod
        def get_self_url_no_query(request_data):
            """
            Returns the URL of the current host + current view.

            :param request_data: The request as a dict
            :type: dict

            :return: The url of current host + current view
            :rtype: string
            """
            self_url_host = OneLogin_Saml2_Utils.get_self_url_host(request_data)
            script_name = request_data['script_name']
            if script_name:
                if script_name[0] != '/':
                    script_name = '/' + script_name
            else:
                script_name = ''
            self_url_no_query = self_url_host + script_name
            if 'path_info' in request_data:
                self_url_no_query += request_data['path_info']

            return self_url_no_query

        @staticmethod
        def get_self_routed_url_no_query(request_data):
            """
            Returns the routed URL of the current host + current view.

            :param request_data: The request as a dict
            :type: dict

            :return: The url of current host + current view
            :rtype: string
            """
            self_url_host = OneLogin_Saml2_Utils.get_self_url_host(request_data)
            route = ''
            if 'request_uri' in request_data.keys() and request_data['request_uri']:
                route = request_data['request_uri']
                if 'query_string' in request_data.keys() and request_data['query_string']:
                    route = route.replace(request_data['query_string'], '')

            return self_url_host + route

        @staticmethod
        def get_self_url(request_data):
            """
            Returns the URL of the current host + current view + query.

            :param request_data: The request as a dict
            :type: dict

            :return: The url of current host + current view + query
            :rtype: string
            """
            self_url_host = OneLogin_Saml2_Utils.get_self_url_host(request_data)

            request_uri = ''
            if 'request_uri' in request_data:
                request_uri = request_data['request_uri']
                if not request_uri.startswith('/'):
                    match = re.search('^https?://[^/]*(/.*)', request_uri)
                    if match is not None:
                        request_uri = match.groups()[0]

            return self_url_host + request_uri

        @staticmethod
        def generate_unique_id():
            """
            Generates an unique string (used for example as ID for assertions).

            :return: A unique string
            :rtype: string
            """
            return 'ONELOGIN_%s' % sha1(uuid4().hex).hexdigest()

        @staticmethod
        def parse_time_to_SAML(time):
            r"""
            Converts a UNIX timestamp to SAML2 timestamp on the form
            yyyy-mm-ddThh:mm:ss(\.s+)?Z.

            :param time: The time we should convert (DateTime).
            :type: string

            :return: SAML2 timestamp.
            :rtype: string
            """
            data = datetime.utcfromtimestamp(float(time))
            return data.strftime(OneLogin_Saml2_Utils.TIME_FORMAT)

        @staticmethod
        def parse_SAML_to_time(timestr):
            r"""
            Converts a SAML2 timestamp on the form yyyy-mm-ddThh:mm:ss(\.s+)?Z
            to a UNIX timestamp. The sub-second part is ignored.

            :param time: The time we should convert (SAML Timestamp).
            :type: string

            :return: Converted to a unix timestamp.
            :rtype: int
            """
            try:
                data = datetime.strptime(timestr, OneLogin_Saml2_Utils.TIME_FORMAT)
            except ValueError:
                try:
                    data = datetime.strptime(timestr, OneLogin_Saml2_Utils.TIME_FORMAT_2)
                except ValueError:
                    elem = OneLogin_Saml2_Utils.TIME_FORMAT_WITH_FRAGMENT.match(timestr)
                    if not elem:
                        raise Exception("time data %s does not match format %s" % (timestr, r'yyyy-mm-ddThh:mm:ss(\.s+)?Z'))
                    data = datetime.strptime(elem.groups()[0] + "Z", OneLogin_Saml2_Utils.TIME_FORMAT)

            return calendar.timegm(data.utctimetuple())

        @staticmethod
        def now():
            """
            :return: unix timestamp of actual time.
            :rtype: int
            """
            return calendar.timegm(datetime.utcnow().utctimetuple())

        @staticmethod
        def parse_duration(duration, timestamp=None):
            """
            Interprets a ISO8601 duration value relative to a given timestamp.

            :param duration: The duration, as a string.
            :type: string

            :param timestamp: The unix timestamp we should apply the duration to.
                              Optional, default to the current time.
            :type: string

            :return: The new timestamp, after the duration is applied.
            :rtype: int
            """
            assert isinstance(duration, basestring)
            assert timestamp is None or isinstance(timestamp, int)

            timedelta = duration_parser(duration)
            if timestamp is None:
                data = datetime.utcnow() + timedelta
            else:
                data = datetime.utcfromtimestamp(timestamp) + timedelta
            return calendar.timegm(data.utctimetuple())

        @staticmethod
        def get_expire_time(cache_duration=None, valid_until=None):
            """
            Compares 2 dates and returns the earliest.

            :param cache_duration: The duration, as a string.
            :type: string

            :param valid_until: The valid until date, as a string or as a timestamp
            :type: string

            :return: The expiration time.
            :rtype: int
            """
            expire_time = None

            if cache_duration is not None:
                expire_time = OneLogin_Saml2_Utils.parse_duration(cache_duration)

            if valid_until is not None:
                if isinstance(valid_until, int):
                    valid_until_time = valid_until
                else:
                    valid_until_time = OneLogin_Saml2_Utils.parse_SAML_to_time(valid_until)
                if expire_time is None or expire_time > valid_until_time:
                    expire_time = valid_until_time

            if expire_time is not None:
                return '%d' % expire_time
            return None

        @staticmethod
        def query(dom, query, context=None, tagid=None):
            """
            Extracts nodes that match the query from the Element

            :param dom: The root of the lxml objet
            :type: Element

            :param query: Xpath Expresion
            :type: string

            :param context: Context Node
            :type: DOMElement

            :param tagid: Tag ID
            :type: string

            :returns: The queried nodes
            :rtype: list
            """
            if context is None:
                source = dom
            else:
                source = context

            if tagid is None:
                return source.xpath(query, namespaces=OneLogin_Saml2_Constants.NSMAP)
            else:
                return source.xpath(query, tagid=tagid, namespaces=OneLogin_Saml2_Constants.NSMAP)

        @staticmethod
        def delete_local_session(callback=None):
            """
            Deletes the local session.
            """

            if callback is not None:
                callback()

        @staticmethod
        def calculate_x509_fingerprint(x509_cert, alg='sha1'):
            """
            Calculates the fingerprint of a formatted x509cert.

            :param x509_cert: x509 cert formatted
            :type: string

            :param alg: The algorithm to build the fingerprint
            :type: string

            :returns: fingerprint
            :rtype: string
            """
            assert isinstance(x509_cert, basestring)

            lines = x509_cert.split('\n')
            data = ''
            inData = False

            for line in lines:
                # Remove '\r' from end of line if present.
                line = line.rstrip()
                if not inData:
                    if line == '-----BEGIN CERTIFICATE-----':
                        inData = True
                    elif line == '-----BEGIN PUBLIC KEY-----' or line == '-----BEGIN RSA PRIVATE KEY-----':
                        # This isn't an X509 certificate.
                        return None
                else:
                    if line == '-----END CERTIFICATE-----':
                        break

                    # Append the current line to the certificate data.
                    data += line

            if not data:
                return None

            decoded_data = base64.b64decode(data)

            if alg == 'sha512':
                fingerprint = sha512(decoded_data)
            elif alg == 'sha384':
                fingerprint = sha384(decoded_data)
            elif alg == 'sha256':
                fingerprint = sha256(decoded_data)
            else:
                fingerprint = sha1(decoded_data)

            return fingerprint.hexdigest().lower()

        @staticmethod
        def format_finger_print(fingerprint):
            """
            Formats a fingerprint.

            :param fingerprint: fingerprint
            :type: string

            :returns: Formatted fingerprint
            :rtype: string
            """
            formated_fingerprint = fingerprint.replace(':', '')
            return formated_fingerprint.lower()

        @staticmethod
        def generate_name_id(value, sp_nq, sp_format=None, cert=None, debug=False, nq=None):
            """
            Generates a nameID.

            :param value: fingerprint
            :type: string

            :param sp_nq: SP Name Qualifier
            :type: string

            :param sp_format: SP Format
            :type: string

            :param cert: IdP Public Cert to encrypt the nameID
            :type: string

            :param debug: Activate the xmlsec debug
            :type: bool

            :param nq: IDP Name Qualifier
            :type: string

            :returns: DOMElement | XMLSec nameID
            :rtype: string
            """
            doc = Document()
            name_id_container = doc.createElementNS(OneLogin_Saml2_Constants.NS_SAML, 'container')
            name_id_container.setAttribute("xmlns:saml", OneLogin_Saml2_Constants.NS_SAML)

            name_id = doc.createElement('saml:NameID')
            if sp_nq is not None:
                name_id.setAttribute('SPNameQualifier', sp_nq)
            if nq is not None:
                name_id.setAttribute('NameQualifier', nq)
            if sp_format is not None:
                name_id.setAttribute('Format', sp_format)
            name_id.appendChild(doc.createTextNode(value))
            name_id_container.appendChild(name_id)

            if cert is not None:
                xml = name_id_container.toxml()
                elem = fromstring(xml, forbid_dtd=True)

                error_callback_method = None
                if debug:
                    error_callback_method = print_xmlsec_errors
                xmlsec.set_error_callback(error_callback_method)

                # Load the public cert
                mngr = xmlsec.KeysMngr()
                file_cert = OneLogin_Saml2_Utils.write_temp_file(cert)
                key_data = xmlsec.Key.load(file_cert.name, xmlsec.KeyDataFormatCertPem, None)
                key_data.name = basename(file_cert.name)
                mngr.addKey(key_data)
                file_cert.close()

                # Prepare for encryption
                enc_data = EncData(xmlsec.TransformAes128Cbc, type=xmlsec.TypeEncElement)
                enc_data.ensureCipherValue()
                key_info = enc_data.ensureKeyInfo()
                # enc_key = key_info.addEncryptedKey(xmlsec.TransformRsaPkcs1)
                enc_key = key_info.addEncryptedKey(xmlsec.TransformRsaOaep)
                enc_key.ensureCipherValue()

                # Encrypt!
                enc_ctx = xmlsec.EncCtx(mngr)
                enc_ctx.encKey = xmlsec.Key.generate(xmlsec.KeyDataAes, 128, xmlsec.KeyDataTypeSession)

                edata = enc_ctx.encryptXml(enc_data, elem[0])

                newdoc = parseString(tostring(edata, encoding='unicode').encode('utf-8'), forbid_dtd=True, forbid_entities=True, forbid_external=True)

                if newdoc.hasChildNodes():
                    child = newdoc.firstChild
                    child.removeAttribute('xmlns')
                    child.removeAttribute('xmlns:saml')
                    child.setAttribute('xmlns:xenc', OneLogin_Saml2_Constants.NS_XENC)
                    child.setAttribute('xmlns:dsig', OneLogin_Saml2_Constants.NS_DS)

                nodes = newdoc.getElementsByTagName("*")
                for node in nodes:
                    if node.tagName == 'ns0:KeyInfo':
                        node.tagName = 'dsig:KeyInfo'
                        node.removeAttribute('xmlns:ns0')
                        node.setAttribute('xmlns:dsig', OneLogin_Saml2_Constants.NS_DS)
                    else:
                        node.tagName = 'xenc:' + node.tagName

                encrypted_id = newdoc.createElement('saml:EncryptedID')
                encrypted_data = newdoc.replaceChild(encrypted_id, newdoc.firstChild)
                encrypted_id.appendChild(encrypted_data)
                return newdoc.saveXML(encrypted_id)
            else:
                return doc.saveXML(name_id)

        @staticmethod
        def get_status(dom):
            """
            Gets Status from a Response.

            :param dom: The Response as XML
            :type: Document

            :returns: The Status, an array with the code and a message.
            :rtype: dict
            """
            status = {}

            status_entry = OneLogin_Saml2_Utils.query(dom, '/samlp:Response/samlp:Status')
            if len(status_entry) != 1:
                raise OneLogin_Saml2_ValidationError(
                    'Missing Status on response',
                    OneLogin_Saml2_ValidationError.MISSING_STATUS
                )

            code_entry = OneLogin_Saml2_Utils.query(dom, '/samlp:Response/samlp:Status/samlp:StatusCode', status_entry[0])
            if len(code_entry) != 1:
                raise OneLogin_Saml2_ValidationError(
                    'Missing Status Code on response',
                    OneLogin_Saml2_ValidationError.MISSING_STATUS_CODE
                )
            code = code_entry[0].values()[0]
            status['code'] = code

            status['msg'] = ''
            message_entry = OneLogin_Saml2_Utils.query(dom, '/samlp:Response/samlp:Status/samlp:StatusMessage', status_entry[0])
            if len(message_entry) == 0:
                subcode_entry = OneLogin_Saml2_Utils.query(dom, '/samlp:Response/samlp:Status/samlp:StatusCode/samlp:StatusCode', status_entry[0])
                if len(subcode_entry) == 1:
                    status['msg'] = subcode_entry[0].values()[0]
            elif len(message_entry) == 1:
                status['msg'] = OneLogin_Saml2_Utils.element_text(message_entry[0])

            return status

        @staticmethod
        def decrypt_element(encrypted_data, key, debug=False, inplace=False):
            """
            Decrypts an encrypted element.

            :param encrypted_data: The encrypted data.
            :type: lxml.etree.Element | DOMElement | basestring

            :param key: The key.
            :type: string

            :param debug: Activate the xmlsec debug
            :type: bool

            :param inplace: update passed data with decrypted result
            :type: bool

            :returns: The decrypted element.
            :rtype: lxml.etree.Element
            """
            if isinstance(encrypted_data, Element):
                encrypted_data = fromstring(str(encrypted_data.toxml()), forbid_dtd=True)
            elif isinstance(encrypted_data, basestring):
                encrypted_data = fromstring(str(encrypted_data), forbid_dtd=True)
            elif not inplace and isinstance(encrypted_data, etree._Element):
                encrypted_data = deepcopy(encrypted_data)

            error_callback_method = None
            if debug:
                error_callback_method = print_xmlsec_errors
            xmlsec.set_error_callback(error_callback_method)

            mngr = xmlsec.KeysMngr()

            key = xmlsec.Key.loadMemory(key, xmlsec.KeyDataFormatPem, None)
            mngr.addKey(key)
            enc_ctx = xmlsec.EncCtx(mngr)

            return enc_ctx.decrypt(encrypted_data)

        @staticmethod
        def write_temp_file(content):
            """
            Writes some content into a temporary file and returns it.

            :param content: The file content
            :type: string

            :returns: The temporary file
            :rtype: file-like object
            """
            f_temp = NamedTemporaryFile(delete=True)
            f_temp.file.write(content)
            f_temp.file.flush()
            return f_temp

        @staticmethod
        def add_sign(xml, key, cert, debug=False, sign_algorithm=OneLogin_Saml2_Constants.RSA_SHA256, digest_algorithm=OneLogin_Saml2_Constants.SHA256):
            """
            Adds signature key and senders certificate to an element (Message or
            Assertion).

            :param xml: The element we should sign
            :type: string | Document

            :param key: The private key
            :type: string

            :param cert: The public
            :type: string

            :param debug: Activate the xmlsec debug
            :type: bool

            :param sign_algorithm: Signature algorithm method
            :type sign_algorithm: string

            :param digest_algorithm: Digest algorithm method
            :type digest_algorithm: string

            :returns: Signed XML
            :rtype: string
            """
            if xml is None or xml == '':
                raise Exception('Empty string supplied as input')
            elif isinstance(xml, etree._Element):
                elem = xml
            elif isinstance(xml, Document):
                xml = xml.toxml()
                elem = fromstring(xml.encode('utf-8'), forbid_dtd=True)
            elif isinstance(xml, Element):
                xml.setAttributeNS(
                    unicode(OneLogin_Saml2_Constants.NS_SAMLP),
                    'xmlns:samlp',
                    unicode(OneLogin_Saml2_Constants.NS_SAMLP)
                )
                xml.setAttributeNS(
                    unicode(OneLogin_Saml2_Constants.NS_SAML),
                    'xmlns:saml',
                    unicode(OneLogin_Saml2_Constants.NS_SAML)
                )
                xml = xml.toxml()
                elem = fromstring(xml.encode('utf-8'), forbid_dtd=True)
            elif isinstance(xml, basestring):
                elem = fromstring(xml.encode('utf-8'), forbid_dtd=True)
            else:
                raise Exception('Error parsing xml string')

            error_callback_method = None
            if debug:
                error_callback_method = print_xmlsec_errors
            xmlsec.set_error_callback(error_callback_method)

            sign_algorithm_transform_map = {
                OneLogin_Saml2_Constants.DSA_SHA1: xmlsec.TransformDsaSha1,
                OneLogin_Saml2_Constants.RSA_SHA1: xmlsec.TransformRsaSha1,
                OneLogin_Saml2_Constants.RSA_SHA256: xmlsec.TransformRsaSha256,
                OneLogin_Saml2_Constants.RSA_SHA384: xmlsec.TransformRsaSha384,
                OneLogin_Saml2_Constants.RSA_SHA512: xmlsec.TransformRsaSha512
            }
            sign_algorithm_transform = sign_algorithm_transform_map.get(sign_algorithm, xmlsec.TransformRsaSha1)

            signature = Signature(xmlsec.TransformExclC14N, sign_algorithm_transform, nsPrefix='ds')

            issuer = OneLogin_Saml2_Utils.query(elem, '//saml:Issuer')
            if len(issuer) > 0:
                issuer = issuer[0]
                issuer.addnext(signature)
                elem_to_sign = issuer.getparent()
            else:
                entity_descriptor = OneLogin_Saml2_Utils.query(elem, '//md:EntityDescriptor')
                if len(entity_descriptor) > 0:
                    elem.insert(0, signature)
                else:
                    elem[0].insert(0, signature)
                elem_to_sign = elem

            elem_id = elem_to_sign.get('ID', None)
            if elem_id is not None:
                if elem_id:
                    elem_id = '#' + elem_id
            else:
                generated_id = generated_id = OneLogin_Saml2_Utils.generate_unique_id()
                elem_id = '#' + generated_id
                elem_to_sign.attrib['ID'] = generated_id

            xmlsec.addIDs(elem_to_sign, ["ID"])

            digest_algorithm_transform_map = {
                OneLogin_Saml2_Constants.SHA1: xmlsec.TransformSha1,
                OneLogin_Saml2_Constants.SHA256: xmlsec.TransformSha256,
                OneLogin_Saml2_Constants.SHA384: xmlsec.TransformSha384,
                OneLogin_Saml2_Constants.SHA512: xmlsec.TransformSha512
            }
            digest_algorithm_transform = digest_algorithm_transform_map.get(digest_algorithm, xmlsec.TransformSha1)

            ref = signature.addReference(digest_algorithm_transform)
            if elem_id:
                ref.attrib['URI'] = elem_id

            ref.addTransform(xmlsec.TransformEnveloped)
            ref.addTransform(xmlsec.TransformExclC14N)

            key_info = signature.ensureKeyInfo()
            key_info.addX509Data()

            dsig_ctx = xmlsec.DSigCtx()
            sign_key = xmlsec.Key.loadMemory(key, xmlsec.KeyDataFormatPem, None)

            file_cert = OneLogin_Saml2_Utils.write_temp_file(cert)
            sign_key.loadCert(file_cert.name, xmlsec.KeyDataFormatCertPem)
            file_cert.close()

            dsig_ctx.signKey = sign_key
            dsig_ctx.sign(signature)

            return tostring(elem, encoding='unicode').encode('utf-8')

        @staticmethod
        @return_false_on_exception
        def validate_sign(xml, cert=None, fingerprint=None, fingerprintalg='sha1', validatecert=False, debug=False, xpath=None, multicerts=None):
            """
            Validates a signature (Message or Assertion).

            :param xml: The element we should validate
            :type: string | Document

            :param cert: The pubic cert
            :type: string

            :param fingerprint: The fingerprint of the public cert
            :type: string

            :param fingerprintalg: The algorithm used to build the fingerprint
            :type: string

            :param validatecert: If true, will verify the signature and if the cert is valid.
            :type: bool

            :param debug: Activate the xmlsec debug
            :type: bool

            :param xpath: The xpath of the signed element
            :type: string

            :param multicerts: Multiple public certs
            :type: list

            :param raise_exceptions: Whether to return false on failure or raise an exception
            :type raise_exceptions: Boolean
            """
            if xml is None or xml == '':
                raise Exception('Empty string supplied as input')
            elif isinstance(xml, etree._Element):
                elem = xml
            elif isinstance(xml, Document):
                xml = xml.toxml()
                elem = fromstring(str(xml), forbid_dtd=True)
            elif isinstance(xml, Element):
                xml.setAttributeNS(
                    unicode(OneLogin_Saml2_Constants.NS_SAMLP),
                    'xmlns:samlp',
                    unicode(OneLogin_Saml2_Constants.NS_SAMLP)
                )
                xml.setAttributeNS(
                    unicode(OneLogin_Saml2_Constants.NS_SAML),
                    'xmlns:saml',
                    unicode(OneLogin_Saml2_Constants.NS_SAML)
                )
                xml = xml.toxml()
                elem = fromstring(str(xml), forbid_dtd=True)
            elif isinstance(xml, basestring):
                elem = fromstring(str(xml), forbid_dtd=True)
            else:
                raise Exception('Error parsing xml string')

            error_callback_method = None
            if debug:
                error_callback_method = print_xmlsec_errors
            xmlsec.set_error_callback(error_callback_method)

            xmlsec.addIDs(elem, ["ID"])

            if xpath:
                signature_nodes = OneLogin_Saml2_Utils.query(elem, xpath)
            else:
                signature_nodes = OneLogin_Saml2_Utils.query(elem, OneLogin_Saml2_Utils.RESPONSE_SIGNATURE_XPATH)

                if len(signature_nodes) == 0:
                    signature_nodes = OneLogin_Saml2_Utils.query(elem, OneLogin_Saml2_Utils.ASSERTION_SIGNATURE_XPATH)

            if len(signature_nodes) == 1:
                signature_node = signature_nodes[0]

                if not multicerts:
                    return OneLogin_Saml2_Utils.validate_node_sign(signature_node, elem, cert, fingerprint, fingerprintalg, validatecert, debug, raise_exceptions=True)
                else:
                    # If multiple certs are provided, I may ignore cert and
                    # fingerprint provided by the method and just check the
                    # certs multicerts
                    fingerprint = fingerprintalg = None
                    for cert in multicerts:
                        if OneLogin_Saml2_Utils.validate_node_sign(signature_node, elem, cert, fingerprint, fingerprintalg, validatecert, False, raise_exceptions=False):
                            return True
                    raise OneLogin_Saml2_ValidationError('Signature validation failed. SAML Response rejected.')
            else:
                raise OneLogin_Saml2_ValidationError('Expected exactly one signature node; got {}.'.format(len(signature_nodes)), OneLogin_Saml2_ValidationError.WRONG_NUMBER_OF_SIGNATURES)

        @staticmethod
        @return_false_on_exception
        def validate_metadata_sign(xml, cert=None, fingerprint=None, fingerprintalg='sha1', validatecert=False, debug=False):
            """
            Validates a signature of a EntityDescriptor.

            :param xml: The element we should validate
            :type: string | Document

            :param cert: The pubic cert
            :type: string

            :param fingerprint: The fingerprint of the public cert
            :type: string

            :param fingerprintalg: The algorithm used to build the fingerprint
            :type: string

            :param validatecert: If true, will verify the signature and if the cert is valid.
            :type: bool

            :param debug: Activate the xmlsec debug
            :type: bool

            :param raise_exceptions: Whether to return false on failure or raise an exception
            :type raise_exceptions: Boolean
            """
            if xml is None or xml == '':
                raise Exception('Empty string supplied as input')
            elif isinstance(xml, etree._Element):
                elem = xml
            elif isinstance(xml, Document):
                xml = xml.toxml()
                elem = fromstring(str(xml), forbid_dtd=True)
            elif isinstance(xml, Element):
                xml.setAttributeNS(
                    unicode(OneLogin_Saml2_Constants.NS_MD),
                    'xmlns:md',
                    unicode(OneLogin_Saml2_Constants.NS_MD)
                )
                xml = xml.toxml()
                elem = fromstring(str(xml), forbid_dtd=True)
            elif isinstance(xml, basestring):
                elem = fromstring(str(xml), forbid_dtd=True)
            else:
                raise Exception('Error parsing xml string')

            error_callback_method = None
            if debug:
                error_callback_method = print_xmlsec_errors
            xmlsec.set_error_callback(error_callback_method)

            xmlsec.addIDs(elem, ["ID"])

            signature_nodes = OneLogin_Saml2_Utils.query(elem, '/md:EntitiesDescriptor/ds:Signature')

            if len(signature_nodes) == 0:
                signature_nodes += OneLogin_Saml2_Utils.query(elem, '/md:EntityDescriptor/ds:Signature')

                if len(signature_nodes) == 0:
                    signature_nodes += OneLogin_Saml2_Utils.query(elem, '/md:EntityDescriptor/md:SPSSODescriptor/ds:Signature')
                    signature_nodes += OneLogin_Saml2_Utils.query(elem, '/md:EntityDescriptor/md:IDPSSODescriptor/ds:Signature')

            if len(signature_nodes) > 0:
                for signature_node in signature_nodes:
                    OneLogin_Saml2_Utils.validate_node_sign(signature_node, elem, cert, fingerprint, fingerprintalg, validatecert, debug, raise_exceptions=True)
                return True
            else:
                raise Exception('Could not validate metadata signature: No signature nodes found.')

        @staticmethod
        @return_false_on_exception
        def validate_node_sign(signature_node, elem, cert=None, fingerprint=None, fingerprintalg='sha1', validatecert=False, debug=False):
            """
            Validates a signature node.

            :param signature_node: The signature node
            :type: Node

            :param xml: The element we should validate
            :type: Document

            :param cert: The public cert
            :type: string

            :param fingerprint: The fingerprint of the public cert
            :type: string

            :param fingerprintalg: The algorithm used to build the fingerprint
            :type: string

            :param validatecert: If true, will verify the signature and if the cert is valid.
            :type: bool

            :param debug: Activate the xmlsec debug
            :type: bool

            :param raise_exceptions: Whether to return false on failure or raise an exception
            :type raise_exceptions: Boolean
            """
            error_callback_method = None
            if debug:
                error_callback_method = print_xmlsec_errors
            xmlsec.set_error_callback(error_callback_method)

            xmlsec.addIDs(elem, ["ID"])

            if (cert is None or cert == '') and fingerprint:
                x509_certificate_nodes = OneLogin_Saml2_Utils.query(signature_node, '//ds:Signature/ds:KeyInfo/ds:X509Data/ds:X509Certificate')
                if len(x509_certificate_nodes) > 0:
                    x509_certificate_node = x509_certificate_nodes[0]
                    x509_cert_value = OneLogin_Saml2_Utils.element_text(x509_certificate_node)
                    x509_cert_value_formatted = OneLogin_Saml2_Utils.format_cert(x509_cert_value)
                    x509_fingerprint_value = OneLogin_Saml2_Utils.calculate_x509_fingerprint(x509_cert_value_formatted, fingerprintalg)

                    if fingerprint == x509_fingerprint_value:
                        cert = x509_cert_value_formatted

            # Check if Reference URI is empty
            # reference_elem = OneLogin_Saml2_Utils.query(signature_node, '//ds:Reference')
            # if len(reference_elem) > 0:
            #    if reference_elem[0].get('URI') == '':
            #        reference_elem[0].set('URI', '#%s' % signature_node.getparent().get('ID'))

            if cert is None or cert == '':
                raise OneLogin_Saml2_Error(
                    'Could not validate node signature: No certificate provided.',
                    OneLogin_Saml2_Error.CERT_NOT_FOUND
                )

            file_cert = OneLogin_Saml2_Utils.write_temp_file(cert)

            if validatecert:
                mngr = xmlsec.KeysMngr()
                mngr.loadCert(file_cert.name, xmlsec.KeyDataFormatCertPem, xmlsec.KeyDataTypeTrusted)
                dsig_ctx = xmlsec.DSigCtx(mngr)
            else:
                dsig_ctx = xmlsec.DSigCtx()
                dsig_ctx.signKey = xmlsec.Key.load(file_cert.name, xmlsec.KeyDataFormatCertPem, None)

            file_cert.close()

            dsig_ctx.setEnabledKeyData([xmlsec.KeyDataX509])

            try:
                dsig_ctx.verify(signature_node)
            except Exception as err:
                raise OneLogin_Saml2_ValidationError(
                    'Signature validation failed. SAML Response rejected. %s',
                    OneLogin_Saml2_ValidationError.INVALID_SIGNATURE,
                    err.__str__()
                )

            return True

        @staticmethod
        @return_false_on_exception
        def validate_binary_sign(signed_query, signature, cert=None, algorithm=OneLogin_Saml2_Constants.RSA_SHA1, debug=False):
            """
            Validates signed binary data (Used to validate GET Signature).

            :param signed_query: The element we should validate
            :type: string

            :param signature: The signature that will be validate
            :type: string

            :param cert: The public cert
            :type: string

            :param algorithm: Signature algorithm
            :type: string

            :param debug: Activate the xmlsec debug
            :type: bool

            :param raise_exceptions: Whether to return false on failure or raise an exception
            :type raise_exceptions: Boolean
            """
            error_callback_method = None
            if debug:
                error_callback_method = print_xmlsec_errors
            xmlsec.set_error_callback(error_callback_method)

            dsig_ctx = xmlsec.DSigCtx()

            file_cert = OneLogin_Saml2_Utils.write_temp_file(cert)
            dsig_ctx.signKey = xmlsec.Key.load(file_cert.name, xmlsec.KeyDataFormatCertPem, None)
            file_cert.close()

            # Sign the metadata with our private key.
            sign_algorithm_transform_map = {
                OneLogin_Saml2_Constants.DSA_SHA1: xmlsec.TransformDsaSha1,
                OneLogin_Saml2_Constants.RSA_SHA1: xmlsec.TransformRsaSha1,
                OneLogin_Saml2_Constants.RSA_SHA256: xmlsec.TransformRsaSha256,
                OneLogin_Saml2_Constants.RSA_SHA384: xmlsec.TransformRsaSha384,
                OneLogin_Saml2_Constants.RSA_SHA512: xmlsec.TransformRsaSha512
            }
            sign_algorithm_transform = sign_algorithm_transform_map.get(algorithm, xmlsec.TransformRsaSha1)

            dsig_ctx.verifyBinary(signed_query, sign_algorithm_transform, signature)
            return True

        @staticmethod
        def get_encoded_parameter(get_data, name, default=None, lowercase_urlencoding=False):
            """Return a URL encoded get parameter value
            Prefer to extract the original encoded value directly from query_string since URL
            encoding is not canonical. The encoding used by ADFS 3.0 is not compatible with
            python's quote_plus (ADFS produces lower case hex numbers and quote_plus produces
            upper case hex numbers)
            """

            if name not in get_data:
                return OneLogin_Saml2_Utils.case_sensitive_urlencode(default, lowercase_urlencoding)
            if 'query_string' in get_data:
                return OneLogin_Saml2_Utils.extract_raw_query_parameter(get_data['query_string'], name)
            return OneLogin_Saml2_Utils.case_sensitive_urlencode(get_data[name], lowercase_urlencoding)

        @staticmethod
        def extract_raw_query_parameter(query_string, parameter, default=''):
            m = re.search('%s=([^&]+)' % parameter, query_string)
            if m:
                return m.group(1)
            else:
                return default

        @staticmethod
        def case_sensitive_urlencode(to_encode, lowercase=False):
            encoded = quote_plus(to_encode)
            return re.sub(r"%[A-F0-9]{2}", lambda m: m.group(0).lower(), encoded) if lowercase else encoded

        @staticmethod
        def normalize_url(url):
            """
            Returns normalized URL for comparison.
            This method converts the netloc to lowercase, as it should be case-insensitive (per RFC 4343, RFC 7617)
            If standardization fails, the original URL is returned
            Python documentation indicates that URL split also normalizes query strings if empty query fields are present

            :param url: URL
            :type url: String

            :returns: A normalized URL, or the given URL string if parsing fails
            :rtype: String
            """
            try:
                scheme, netloc, path, query, fragment = urlsplit(url)
                normalized_url = urlunsplit((scheme.lower(), netloc.lower(), path, query, fragment))
                return normalized_url
            except Exception:
                return url