How Clipperz works
Clipperz lets you submit confidential information into your browser, but your data are locally encrypted by the browser itself before being uploaded. The key for the encryption processes is a passphrase that never gets sent or saved to the server! Therefore no one except you can access your data.
Clipperz is simply in charge of delivering the Ajax code to your browser and then storing your data in an encrypted form on its servers. All encryption and decryption operations take place inside your browser.
Zero-knowledge
Clipperz password manager is the first zero-knowledge web application. This means that Clipperz knows nothing about its users and their data. Not even their usernames!
Clipperz exploits Ajax and browser-based cryptography to build applications that users can wholeheartedly adopt to manage their private data.
Trust and transparency
We got used to trust third parties with our data (photos, documents, spreadsheets, …) to enjoy the convenience of online services. Clipperz proves that this is not always necessary: users can finally benefit from a web application without the need to share their data with the web application provider.
But how users can be sure that their data cannot be read by others, not even by Clipperz?
The short answer is: do not trust Clipperz, but check for yourself or rely on the community of users and experts instead!
Clipperz believes in complete transparency, therefore the whole source code of the application is freely available for security reviews.
Why Ajax?
Ajax holds the key to pure browser-based data encryption and decryption. Standard cryptography algorithms could be implemented with Javascript and executed within the browser, but Javascript can’t remember data between page loads. This causes an annoying issue since it forces the user to re-enter the passphrase each time.
An app developed with Ajax sends requests to the server in background and uses the power of DHTML to write updates to the page, i.e. it tends to not actually do page transitions, hence solving the problem of keeping a persistent key to perform crypto operations.
128-bit security level
Clipperz password manager is a cryptographic system with a 128-bit security level. This means that to be successfully attacked it will require the attacker to perform at least 2128 “steps” of some kind of work. It’s a vague definition since each step could be as simple as a table lookup or as complex as performing an involved computation task. But it’s good enough to design a strong cryptographic system.
Cryptographers agree that a 128-bit security level will be sufficient against brute-force attacks into the foreseeable future. But, of course, no aspect of a system design should be overlooked, from the choice of algorithms to usage policies.
But why using AES-256 or SHA-256? Because there is not a one-to-one relationship between the security level and the main parameter of a cryptographic primitive (e.g.: key size for ciphers, output size for hash functions, …). Read also this blog post.
Other security features
No dynamic code download
Clipperz is a huge Javascript program. However the whole source code is downloaded to your browser before you login. Not a single line of Javascript code is moved to your browser afterward. more …
Password strength indicators
Could you gauge the strength of your passwords? Luckily Clipperz provides visual indicators. You can spot weak passwords and substitute them with strong ones. more …
Application locking
Users can manually or automatically lock-up the Clipperz interface and their data.
SSL secure connection
All data is encrypted and decrypted inside your browser and only encrypted data is ever sent over the Internet. Nonetheless encrypted data is delivered via an SSL connection to make things even more secure.
One-time passphrase
It works like your regular passphrase, but it can be used only once. When logging to Clipperz from public computers it’s strongly advisable to use one-time passphrases.
Mask for password fields
Passwords fields are displayed with the usual stars, but if needed, users can copy the actual password to the clipboard by simply selecting the stars.
Password generator
A very simple and secure tool to generate long and complex passwords. It helps to never re-use the same password over and over.
Automatic updates
Cryptographic algorithms evolve with the times. Clipperz can upgrade its crypto foundations without the users even notice it.

Third party evaluation?
I’d be interested in seeing a third party evaluation of the security of this.
3rd party eval
I too would be interested in a obviously professional and in-depth 3rd party review/audit of all of the code, system, and people behind it.
I can likely trust it for everyday website logins, but before any proud geek uses it to store credit card info, we want independent verification… multiple, reliable sources if possible.
Great work you are putting out there. Seriously. I had the same exact idea in my head for the past 1.5 years, but never acted on attempting anything. If you win the trust of people, it will be a big success, not small. Best of luck.
Professional reviews vs. community reviews
Any third party review is certainly welcome, but there are some problems:
we cannot afford the relevant amount of money that a security professional will ask; and since we frequently release new versions …
conflict of interests: will your trust level increase if we pay a 3rd party to analyze Clipperz security?
We opted since the beginning of this venture for complete transparency and community reviews. This is why we provide instructions about how to download our source code.
This is also why we released the core crypto functions under a
BSDAGPL license. See ourClipperzJavascript Crypto Library.What do you think of our approach? Any suggestion?
Thanks, Marco
Security and user trust ideas
I think that you are presenting the concern near the best that you can with your resources (although, you may want to spell out your resources, see bullet below). Your ideas are huge leaps in the right direction, but there is always more that you can do.
Here are some thoughts and ideas to provide cheap security peace of mind to potential users:
First, by professional, I did not necessarily mean paid. Eventually, there are going to be open source advocate organizations, security focus groups, conferences, etc, that will see these new online password management projects. I consider some groups, and people like the above to be ‘professional’. Many non-profit groups, conferences, and security web sites, do handle a budget, donations, etc. This is very much professional, and also their public credibility go a long way.
Local vs server password
Is the same password used when logging in at clipperz.com as is used when encrypting the data locally?
Re: Local vs server password
The short answer is “no”.
The long answer is too long to be tell on a comment, but I will try to point out the main elements:
If you are interested in more details, please join our discussion group
[1] the full formula is srp_password = sha-d256(passphrase + username); you can find it on the source file src/js/Clipperz/PM/Connection.js, at line 503
can this be cracked?
simple question - simple YES / NO appreciated! I imagine (not an expert) the answer is YES but only through Brute Force?
Ask the community!
Dear Sam, what about posting your question to forums and discussion groups focused on security and cryptography?
Clipperz, as any security system, is not just a collection of crypto algorithms, but it consists of many other components including the users!
Therefore it would be very interesting to have more people with different skills answer your question. However I doubt it could a yes/no answer.
Thanks, Marco
Thanks for the response
Thanks for the response Marco although you didnt really answer my question ;) - frankly I am an “average user” thus have no interest in exploring the in-depth nature of cryptography on various forums - most of your users will be like me! I am however interested in using Clipperz and would expect you to have a view on my question rather than tell me to go elswhere since YOU are asking for my passwords.
Asking around, I believe this like really anything can be cracked - probably at present through brute force and wouldnt be worth the effort if someone did manage to get a hold of your severs. This to me seems an acceptable level of risk and is not something you should be afraid of explaining to your users!
All the best Sam
Every seller praises his wares ...
Dear Sam, we are not asking our users to trust us, but to check for themselves or ask the community of security experts.
This is why I did not answer your question, after all every seller praises his wares, so my answer wouldn’t be of any help …
We believe Clipperz is a strong cryptographic system that can greatly enhance the security of its users (otherwise I would never ask your passwords and confidential data).
That said, even if you are an average user you should put more values in a third party evaluation of Clipperz than in any declaration from its developers.
Regards, Marco
Continued Service Availability
I love the Clipperz service.
My questions has to deal with continued availability. If I spend a bunch of time to input data into the system, how can I ensure that the service will be there a year from now? Obviously, I can download a local copy regularly to protect myself.
Here’s the deal. Clipperz doesn’t have contact information for it’s users. This is a real selling point of the service.
As a result, there is no way for Clipperz to send out an email warning users that the service is going away and to instruct people to pull down their data.
One idea might be to allow users to subscribe to some sort of company news list, which is separate and apart from the user list. This might be confusing to people.
We are perfectly aware of
We are perfectly aware of this communication issue; this is why we have set up a forum even before starting advertising the service.
We encourage all our users to subscribe to the forum, as it is a nice way to keep up to date with the evolution (and sometimes also shortcomings) of our service.
It is highly patrolled (even if we are only a two guys shop, we really care about our users), and you can see by yourself the rate and responsiveness of our replies.
But we have also other options to keep our users updated.
We are now investigating how to notify our users of relevant updates through the application itself, but we are very careful about it as we really don’t want to weaken the security of the application doing it.
Hope this addresses some of your concerns.
Using Clipperz on a shared PC
I’m just getting into using Clipperz and find the anonymity and ‘zero-knowledge’ aspect really appealing. However, as I am not technically-minded enough to understand all the cryptograhic aspects of the site can you reassure me on something? When I use Clipperz on my PC at home I understand that all the confidential information is encrypted by my browser. That’s fine. However, how secure is this when I using, say, a PC in an Internet Cafe or my local Public Library? In such situations it is not ‘my’ browser…
Hoping you can put my mind at rest! btw- I prefer your site to PassPack!
Some advices
Dear Paul,
thanks for your kind words!
When accessing Clipperz from a public PC, I would recommend the following measures:
Avoid using any installed browser by bringing with you Portable Firefox, launch it from your USB drive or iPod.
Sign in to Clipperz using a one-time passphrase and not your regular passphrase. (this long-awaited feature will be released next week!)
And, if the untrusted PC does not have an Internet connection, move to the USB drive also your offline copy.
best regards,
Marco
What about publishing all code under gpl?
i understand that the reason for not opening code is the great opportunity to make some money and obviously need for some payoff for all the resources and work which you put into the development…
is there any other reason which you found for not publishing all the code under gpl?
Who would benefits from a GPL license?
Sorry, but I can not understand who could benefit from our code being released under GPL licence.
Could you share some interesting cases that are not achievable with the current license, but would be possible using a GPL licence?
application locking
by manipulating the DOM, it was easy to override the locking (by simply removing the elements off the page). The “Nuke anything” extension for firefox makes this a 5 second job.
re: application locking
The current implementation of the locking feature is very “thin”, security wise.
This is one of the reasons we have not implemented yet an auto-lock in the main interface (the compact version, if used in a sidebar, is somewhat more secure, as the browsers plug-ins can not access its content as easily; nothing rock solid, but a little more secure).
We are aware of this weakness, and we are planning for a much more solid solution in a future release of the application.
PS: thanks for the pointer to the interesting Firefox plug-in.
How exactly my passpharse can never be sent to server?
When I download index.html to my computer, I must enter passphrase in order to access the data. Therefore, this passphrase must be checked against something. And this “something” must be included in the index.html, which is downloaded from the server.
How does server know what to check, if it never receives the passphrase?
Sorry if this is obvious, but I’m really stuck :)
Thanks, Aleksey.
Re: How exactly my passpharse can never be sent to server?
Aleksey,
first let me fix a wrong assumption you wrote in your comment:
This is not correct. The index.html file is a static file, and it is the same for everybody. No personal information is stored in it; this is not the case for the offline version, but I don’t think this is relevant for the moment.
Your credentials are compared with some data stored on the server, but thanks to the SRP protocol we can achieve this without sending the passphrase itself to the server. Only derivate values are transmitted; if you like some algebra, look here.
"Delete account" feature
A bit of questions: - Does Clipperz allow me to delete my account later? - If yes, will Clipperz delete every information in my account?
Sorry if these are already covered, I am just a bit concerned to even try Clipperz if I don’t have the answers to these questions. Thanks.
Re: "Delete account" feature
You need to go to “account” -> “delete your account”.
We ask for your username and passphrase (just to be sure that is not somebody else trying to delete your account left open on your computer) and we will delete everything from our online DB, access history included.
The only data left will be the one on the backups.
I see. Thanks for the
I see. Thanks for the answer. :)
Am I right, that if you want
Am I right, that if you want to, you could change your JS and your checksums and you get all the passwords from every user enters its registration data?
Re: Am I right, that if you want
The short answer is YES; we could change the JS in order to collect all our users’ username and passphrase.
What we are hoping is going to happen, is that as soon as the checksum changes, someone will compare the current version of the application with the previous one (we have all the code of all the different versions of the application readily downloadable) and check that the changed code will do no harm to the security of the whole system.
Keeping all the version always available also allow anybody to check if in the past we have tried to do scary things.
We perfectly understand that not everybody will be able to perform an accurate assessment of the code; but it will be enough for just a single person to find a problem, for the whole project to be immediately dismantled.
I don’t know if this is a sound enough answer to your question, but we have no other definitive answer right now.
Double access technique / double data security
I’m currently a Passpack user and I guess I chose Passpack over Clipperz partly because of the double data security - one password to get the data and another to unpack it. I’m starting to wonder if this really improves security (much) … Could you please comment on this?
Off-topic: I assume Clipperz isn’t supporting HTTP Basic Auth yet - at least that is the biggest drawback for me when using Passpack. Do you have any plans to do so or any ideas on how to do it?
HTTP Auth supported
@ Hans Frederik
I cannot comment on Passpack’s implementation because the source code is not available, at least not in an intelligible form. The authentication protocol where the first password is used is not known to me. Similarly I have no info about the key derivation algorithm that processes the second password.
I can only say that remembering one long and strong password is easier then remembering two long and strong passwords. :-)
HTTP Basic Auth is definitely supported by Clipperz! You can easily have a 1-click login to any web site that uses HTTP Auth. There is a dedicated tool to quickly create such a link.
Marco
Too complicated.
Too complicated.
Excelente
It’s a excellent program. Congratulations.
Error
I heard all about clipperz and tried it a few days ago and had problems hope everything was taken care of.Will try again in the future.
I believe Clipperz is a
I believe Clipperz is a strong cryptographic system that can greatly enhance the security of its users.
Password Security
To Further enhance password security I like your password generator. Problem is that your password generator doesn’t seem to generate a certain number of characters and Numbers are missing…
I would love it if you downloaded the code for cryptnos.
It’s open source :
http://www.cryptnos.com/online/
It’s a great Idea basically you come up with a unique passphrase and a site and encryption parameters and hit generate and it generates your passwords.
Can you imagine even further zero knowledge you save the passphrase “Master Password” in the password card and all the user has to do is remember the parameters to generate their actual password.
For the paranoid. Or like I said above a better random password generator.
It’s free and I just saw it today and figured you guys could easily implement it.
http://www.cryptnos.com
@Josh Cryptnos is quite
@Josh
Cryptnos is quite similar to the original PwdHash from Stanford. It’s a smart idea, but it ‘s something different from a password generator.
Why are you saying that Clipperz password generator “doesn’t seem to generate a certain number of characters …”? Can you elaborate more on this? If you have evidence of a misbehavior we would like to fix it! Thans.
RE: @Josh Cryptnos is quite
On the provided password generator, try Choosing Low, Upper, Special and Numbers.
Tell me all the time the amount of everything.
The amount of #’s is somehow always shorter.. sometimes even non-existent.
I am not here to criticize your password generator.
I just like choice.
I may also be a little bit on the paranoid side.
And while I understand that Cryptnos is not a Random password generator you can store your cryptnos (non-encrypted) passphrase in the password field inside your clipperz card.
All the user has to remember are the encryption parameters and know what site they want a password for. They then take the (non-encrypted) password inside their clipperz card and put it in the ‘Passphrase’ field of cryptnos and hit generate to generate their ‘REAL’ password. It uses a freely available source and it’s even another layer of security inside of clipperz. It also makes it even more “zero knowledge”.
Thanks Josh. We will
Thanks Josh. We will certainly verify the wrong behavior you are reporting and get back to you.
Being slightly paranoid is a very much appreciated virtue here! :-)
Browser base encryption
Browser base encryption techniques are much better & safe, as here in the case of Clipperz. I’ve not yet used this tool but after going through this article I must try it.
Now data security is a major issue because many online crime occurring through data theft. I’ve already used password management & quite happy with its service still I want to try new ones. I hope Clipperz will be a nice & useful tool for me.
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