1. Modern authentication
techniques in Python web
applications
Artur Barseghyan
Goldmund, Wyldebeast & Wunderliebe
http://www.goldmund-wyldebeast-wunderliebe.nl/
artur.barseghyan@gmail.com
https://github.com/barseghyanartur

2. Part 1
Single Sign-on
using
Central Authentication Service

3. A single framework/application
User base
Framework/application
Authentication system
Other importants parts not
related to this talk

4. Typical framework/application authentication flow
User requests content
requiring authentication
User gets the
content requested
Is user
authenticated?
Authenticate
user
User provides credentials
(login page)
Are
credentials
correct?
Yes
No Yes
No

5. Multiple web frameworks/applications
User base 1
Framework/application 1
Authentication
system 1
Other importants parts
not related to this talk
User base 2
Framework/application 2
Authentication
system 2
Other importants parts
not related to this talk
User base N
Framework/application N
Authentication
system N
Other importants parts
not related to this talk
...
Web portal (ex. DMS, intranet, wiki, etc.)

6. Without Single Sign-on...
● Use a single framework/application and write lots of
apps OR
● Use multiple frameworks/applications and:
○ Hack their authentication systems OR
○ Expect users to login into each of them OR
○ Make them communicate via customly built API
● More (bad) ideas?

7. With Single Sign-on...
● User logs in once and gains access to all systems
without being prompted to log in again.

8. (JaSig) CAS
Enterprise Single Sign-on solution
● Open source
● Well documented
● Scalable
● Modular and highly pluggable (MySQL,
PostgreSQL, Oracle, LDAP, SPINEGO,
RADIUS, etc.)
● Lots of ready-to-use clients and plugins

9. (JaSig) CAS
CAS involves at least three parties:
● A client web browser
● Web application requesting authentication
● The CAS server
It also optionally may involve:
● Back-end service, such as a database server

10. CAS authentication flow

11. CAS authentication schema
User requests content which
requires authentication
User is asked to
provide credentials
(login page)
Create SSO token
and redirect
User gets the
content requested
No
Yes
No
Yes
Is user
authenticated
into app?
No
Yes
Authenticate
user (CAS)
CAS server
Authenticate
user (locally)
Are
credentials
correct?
Is user
authenticated
into CAS?
CAS client (web application)

12. Pros of CAS
Pros
● Centralised authentication for all frameworks/applications.
● Actively maintained and developed. Large community.
● Modular and highly pluggable (MySQL, PostgreSQL, Oracle, Active
Directory, LDAP, SPINEGO, RADIUS, etc.).
● Lots of ready-to-use packages for many frameworks/applications.
● Less passwords to retype, remember and recover.
● More of your own code is reusable.
● Happier end-users.
● REST API.

13. Cons of CAS
Cons
● SSO availability becomes critical.
● SSO security becomes critical.

14. Our use case
Dashboard app
● Django
Server A
CAS server
Server C
User base
● Active Directory
Server D
VPN
● Apache
● Tomcat
● Debian
● Java
● CAS
● OpenVPN
● AJP
● Python
● Django
● Plone
More to come
Server X
DMS
● Plone
Server B

15. Conclusion

16. CAS alternatives
1 / n
JOSSO http://www.josso.org
OpenAM (formerly known as OpenSSO) http://openam.forgerock.org
Pubcookie http://www.pubcookie.org
CoSign http://weblogin.org

17. Linkodrome
1 / n
Software packages
JaSig CAS http://www.jasig.org/cas
Django CAS client https://github.com/Goldmund-Wyldebeast-Wunderliebe/django-cas-consumer
Plone CAS client https://github.com/collective/anz.casclient
Detailed installation instructions
http://bit.ly/1uuk2BS

18. Part 2
Two-step verification
(Two-factor authentication)

19. Standard authentication flow
User requests content
requiring authentication
User gets the
content requested
Is user
authenticated?
Authenticate
user
User provides credentials
(login page)
Are
credentials
correct?
Yes
Yes
No
No

20. ● Knowledge factor ("something only the user
knows"): a password or a PIN.
● Possession factor ("something only the user has"):
ATM card, smart card, mobile phone.
● Inherence factor ("something only the user is"):
Fingerprint or voiceprint.
Standard authentication factors

21. Common advises on remembering
many passwords
● Use complex passwords and have them saved in
password managers.
● Use complex passwords, write them on paper and
carry them in your wallet.
Passwords aren’t enough!

22. Two-factor authentication
● Knowledge factor ("something only the user knows"):
a password or a PIN.
● Possession factor ("something only the user has"):
ATM card, smart card, mobile phone.
● Inherence factor ("something only the user is"):
Fingerprint or voiceprint.

23. Standard authentication flow
User requests
content requiring
authentication
User
provides
credentials
No
Yes
Is user
authenticated
?
Authenticate
user
Yes
No
Are
credentials
correct?
User gets
the content
requested

24. Two-factor authentication flow
User requests
content requiring
authentication
User
provides
credentials
No
Yes
User
provides
second
factor
token
Is
token
correct
?
Yes
No
Second factor
Is user
authenticated
?
Authenticate
user
Yes
No
Are
credentials
correct?
User gets
the content
requested

25. (Common) solutions
● SMS authentication
● Google Authenticator (mobile app)
● Hardware token generators

26. Google Authenticator

27. Hardware token generators

28. Our use cases
● collective.googleauthenticator (uses Google
Authenticator app)
● collective.smsauthenticator (login codes sent by SMS)

29. collective.googleauthenticator

30. Setup two-step verification

31. Authenticate

32. Verify

33. Conclusion

34. Alternatives
● Risk-based authentication (based on behavioral
biometrics, keystroke dynamics, etc.)
● Strong authentication
● Reliance authentication

35. Linkodrome
Plone
● collective.googleauthenticator (two-factor authentication using Google Authenticator app)
https://pypi.python.org/pypi/collective.googleauthenticator
● collective.smsauthenticator (two-factor authentication using login codes sent by SMS)
https://pypi.python.org/pypi/collective.smsauthenticator
Django
● django-two-factor-auth (two-factor authentication using Google Authenticator or login codes sent
by SMS)
https://pypi.python.org/pypi/django-two-factor-auth
● django-otp (pluggable framework for adding two-factor authentication using OTP.)
https://pypi.python.org/pypi/django-otp

36. Questions?

37. Thank you!
Artur Barseghyan
Goldmund, Wyldebeast & Wunderliebe
artur.barseghyan@gmail.com
https://github.com/barseghyanartur