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My weekend project - AES encryption for Gmail or anything else
- jvehent 15y agoNicely done. Roundcubemail has been struggling with email encryption for a while now. I would love to see you solution in a plugin: http://trac.roundcube.net/wiki/Plugin_Repository http://trac.roundcube.net/wiki/Plugin_Repository
- zitterbewegung 15y agoThats pretty neat since you have of the encryption done client side. Which mode of AES do you use?
- eran 15y agoI use counter mode with 256 bit key Key is generated as sha256 hash of the user password
- tptacek 15y agoThat's also not a secure way of generating an AES key; those crypto keys can be cracked quickly. The problem you're trying to solve is the entire reason for PBKDF2. You should also use SJCL's AES.
- bdhe 15y agoYou should also use SJCL's AES. Here's the link: http://bitwiseshiftleft.github.com/sjcl/ http://bitwiseshiftleft.github.com/sjcl/
- e-dard 15y agoThis is neat. Would it be possible to extend it such that you could drop a key file into the password box to do the encryption/decryption?
- eran 15y agoSure, but on modern browsers only (utilizing html5 file API). I am thinking about implementing RSA private key generation and online public key registry in future.
- scrrr 15y agoVery cool. Something like that for GPG encrypted emails would be great.
- Inufu 15y agoSee http://news.ycombinator.com/item?id=2654065 http://news.ycombinator.com/item?id=2654065
- megamark16 15y agoThis is great, I was just thinking the other day that it should be possible to encrypt gmail messages. Now you should make it possible to encrypt GChat messages automatically when I hit Send, and then decrypt them when they are received, that way they are encrypted end to end, instead of just between my browser and the server :-)
- evanw 15y agoIf you use Pidgin, you can do just that with the Pidgin-Encryption plugin. Both parties need the plugin installed, though. http://pidgin-encrypt.sourceforge.net/ http://pidgin-encrypt.sourceforge.net/
- mkelly 15y agoOTR supports this for pidgin, and has a proxy for other clients: http://www.cypherpunks.ca/otr/ http://www.cypherpunks.ca/otr/
- pixdamix 15y agojavascript:(function(){document.body.appendChild(document.createElement('script')).src='http://encipher.it/javascripts/inject.js';})(); You should consider moving to https. After all, what's the point in providing this kind of script if anyone can MITM it ? Besides that, this is pretty cool. Could you provide a standalone bookmarlet which doesn't need to download any scripts ?
- eran 15y agoYes, I will install ssl cert in future (at least self signed), understand the risk. Standalone bookmark is great idea, but I am not sure if I can fit script to 2048 bytes. Maybe, I'll make html5 cache manifest to avoid network access.
- tptacek 15y agoEven if you could somehow minify all of AES into a bookmarklet, you'd still lose any time any page this ran from requested HTML or JS from a non-HTTPS link, since any of those requests could poison the runtime.
- nextparadigms 15y agoWould using SPDY help?
- amalcon 15y agoNot in and of itself. Google runs SPDY over SSL, just as they also run HTTP over SSL (HTTPS). It's the SSL that makes it secure. Once you're running one protocol over SSL, you might as well run all of them over SSL. The basic problem here is that JS is too dynamic to ensure this type of security. Any script running on the page can rebind any value, monitor or trigger any event, or a number of other things. Without SSL or similar, an attacker can inject any script they want into the page. The simplest variant of such an attack would be a script that replaces your AES function with a ROT13 or other useless cipher. There are variations on this theme, and in the end it's impossible to defend against all of them.
- woodall 15y ago>Weekend project >encryption Choose one.
- hollerith 15y agoAlso: "Browser-based." "Secure." Choose one.
- agentultra 15y agoWhile I won't point out the technical reasons why encryption is hard, I will say that I think this project is cool. I think encryption is something more people might use if it were accessible. But it's hard enough as it is without making it so easy that Joe Sixpack could use it -- especially since implementations as we know it require Joe Sixpack to understand what he's doing or else the encryption fails. However, tools like this at least give us prototypes for ideas that could one-day bridge the gap. Good job, dude. Hope you stick with it and find a way to make it better.
- Shenglong 15y agoI found your "Joe Sixpack" reference extremely comical.
- Ixiaus 15y agoI feel like this would be better as a browser extension instead of a bookmarklet... I get a bit queasy about the potential for MITM with this implementation. An extension that could bring GPG to the mix, would be VERY awesome (if that doesn't exist, I actually haven't tried searching for that...). Cool project though :)
- jgrahamc 15y agoYour key derivation function is pretty weak. Looking at your code you are doing SHA256(password entered by user). You should take a look at using http://en.wikipedia.org/wiki/PBKDF2 http://en.wikipedia.org/wiki/PBKDF2 for the key derivation. SHA256 is really fast and given that you are getting entropy from some user entered password (which is likely to be badly chosen) you want something _slow_ to derive the key. Hence PBKDF2 with lots of iterations.
- eran 15y agoThank you point me out. Definitely, I need to implement PBKDF2 (and add salt to password). I planning this, but weekend is too short and finally I just put SHA256 for key derivation. But, until you describe, I do not recognize what the principal difference between hash and password based key derivation function, thanks.
- Xk 15y agoI assume you know that the reason you add a salt is to prevent rainbow table attacks. Without a salt, if someone obtains the hash then they need to just run it through a single rainbow table and with very high probability, obtain the password. A SHA{1,2,3,128,256,512} hash is very VERY VERY fast. So fast, in fact, that an attacker who has the hash could easily run through all 8 character passwords given a few GPU machine clusters. PBKDF2 is very much like a SHA hash, but it is repeated over and over. Instead of just salt||SHA1(password||salt) you compute salt||SHA1(SHA1(SHA1(SHA1(SHA1(password||salt))))). This makes it so an attacker with the hash has to do much more work in order to brute force the password. Now, that's not exactly how it works, but just read the wikipedia article for that.
- pjscott 15y agoWhat you described is essentially PBKDF1, which is similar to PBKDF2, but only supports a fixed output key length. It's also a decent option; just not as flexible as PBKDF2.
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- Erwin 15y agoNote that Gmail automatically saves your draft as you type it. So while this will offer some protection for the message while it's in transit from Google's server to your destination, your unencrypted message draft will still be sent to Google's servers (and given Google Apps' distributed architecture, I'm not sure you can determine where that unencrypted copy could end up or when it'd be erased). Perhaps a way around that could be to enhance a text input field so that only the final encrypted message is written to it, so Google's app does not see the plain text.
- niels_olson 15y agoFiregpg used to support disabled drafts
- moe 15y agoWouldn't it make more sense to revive FireGPG[1] and, while you're at it, port it to all other major browsers? I am still disappointed that PGP in the browser never gained traction. Not only would it help with e-mail security, it could also be used for passwordless website logins, portable web identities, all that jazz[2]. One proper, user-friendly browser plugin could put an end to all those nasty kludges called OAuth, OpenID, LastPass, etc... [1] http://getfiregpg.org/s/home http://getfiregpg.org/s/home [2] http://en.wikipedia.org/wiki/Web_of_trust http://en.wikipedia.org/wiki/Web_of_trust
- IgorPartola 15y agoAre there any webmail providers out there that support PGP? GMail never will since it needs the ability to read your email to show you ads.
- eli 15y agoHushMail and Countermail do. I think it never really caught on because if you really care about end-to-end security, you wouldn't be using a webmail provider.
- biafra 15y agoIf you had a working (and secure) crypto on the client side you could use a webmail provider and still be secure. I can imagine an extension for Chrome or Firefox that will not be updated without my knowledge and has been peer reviewed like gnupg.
- IgorPartola 15y agoAs long as the extension does not then place the cleartext back into the DOM. I would also want support on my Android phone too. So I guess basically, it's never happening.
- eli 15y agoIf I can't safely check my mail from random computers anyway, I'd just as soon remove the browser from the equation and use a GPG-compatible mail client.
- antihero 15y agoThis is an awesome way of doing things. I'm going to be doing a slightly different implementation of this for my WIRE project on the advice of a bunch of people (more intense key differentiation, for a start), but it's good to know people are starting to do this :)
- antihero 15y agoEdit: Just finished implementing this using the Stanford library - check it out (non-SSL test site) http://wire.0xf.nl http://wire.0xf.nl
- eskimoYoYo 15y agoGotta say, awesome work so far! Encryption aside, this is a great concept.
- VMG 15y agohttp://news.ycombinator.com/item?id=639647 http://news.ycombinator.com/item?id=639647 Typing The Letters A-E-S Into Your Code? You’re Doing It Wrong
- fduran 15y agoThis tool is interesting and the page has a nice design. I also created recently a weekend project based on client-side encryption: https://whisperpassword.com https://whisperpassword.com , I need to learn about design though ;-)
- js4all 15y agoThis is interesting, but s/mime is the proper way to encrypt and/or sign emails. I am not sure though, if it is possible to create a multipart message using JavaScript in gmail.
- mtogo 15y agoHmm, testing it out it constantly confuses weather it should be encrypting or decrypting. I've tried to enter a message and had it request a decryption password. That combined with the poor crypto practices makes it rather unusable, but it's a fantastic concept! Just needs a bit of work.
- jahmed 15y agoVery nice. I've been thinking of something like this for my project as well. The problem I face is how do you securely exchange the key.
- jrockway 15y agoWho are you protecting the message from when you do this? Gmail? But they can just send the cleartext to the server before you click "encrypt it", and in fact they do (drafts). Don't type stuff into a program you didn't write if you don't want the author to see it.
- drdaeman 15y agoObligatory link to Nate Lawson's article on in-page crypto: http://rdist.root.org/2010/11/29/final-post-on-javascript-crypto/ http://rdist.root.org/2010/11/29/final-post-on-javascript-cr...
- coverband 15y agoYou might also want to fix the typo: "Firefox or Goole Chrome:" (missing _g_ in Google)
- sweis 15y agoThis implementation is broken. It concatenates a hash of the plaintext to a CTR-mode ciphertext. That's weakly authenticated and leaks information about the plaintext. It would be better to HMAC the ciphertext with a second key value.
- eran 15y agoFixed. Thank you for advice about HMAC, now I am use it.
- nextparadigms 15y agoCheck this out and see if it can help in any way (at least for Chrome): http://blog.chromium.org/2011/06/new-chromium-security-features-june.html http://blog.chromium.org/2011/06/new-chromium-security-featu...
- nopassrecover 15y agoI'm pretty amateur on cryptography, and this is cool and everything for basic security, but for those more in the know does the fact that the algorithm knows a password is "wrong" weaken the cryptography (I realise it's a cool feature of this app, I'm talking generally)? Presumably you would have to test each decrypted result for language words etc. otherwise to know if you had decrypted it correctly.
- yan 15y agoOr prepend a known header to the plaintext you're encrypting..