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Re: Javascript Cryptography Considered Harmful

From: David Dahl <ddahl@mozilla.com>
Date: Wed, 21 Sep 2011 13:36:03 -0700 (PDT)
To: John Kemp <john@jkemp.net>
Cc: Henry Story <henry.story@bblfish.net>, public-identity@w3.org
Message-ID: <715796116.95858.1316637363642.JavaMail.root@zimbra1.shared.sjc1.mozilla.com>

A key generated for origin A can never be used for origin B. In fact, the private keys are inaccessible to content JS entirely.

No doubt there are still issues, regardless. Web devs are leading here with very unsafe all-in-JS crypto primitives - and key handling. The main point is that DOMCrypt gives developers well-worn crypto primitives that have been in browsers for years. 



----- Original Message -----
From: "John Kemp" <john@jkemp.net>
To: "David Dahl" <ddahl@mozilla.com>
Cc: "Henry Story" <henry.story@bblfish.net>, public-identity@w3.org
Sent: Wednesday, September 21, 2011 3:12:30 PM
Subject: Re: Javascript Cryptography Considered Harmful

On Sep 21, 2011, at 3:55 PM, David Dahl wrote:

> I provided feedback through this blog post: http://monocleglobe.wordpress.com/2011/08/30/javascript-and-crypto/

One of the concerns of the blog post is that if you trust the server to deliver you code for doing crypto, why don't you trust the server to "just" do SSL? 

In the DOMCrypt proposal, can an origin generate a key and tell the client to use it? If so, how does that deal with the MITM which tells the browser to create a key for some origin, and then encrypt the user's password and send it to the server with that origin?


- John

> Regards,
> David
> ----- Original Message -----
> From: "Henry Story" <henry.story@bblfish.net>
> To: public-identity@w3.org
> Sent: Wednesday, September 21, 2011 2:22:52 PM
> Subject: Javascript Cryptography Considered Harmful
> An interesting article. I have not yet read it through in detail. I was wondering what people made of it here.
> http://www.matasano.com/articles/javascript-cryptography/
> Henry
> Social Web Architect
> http://bblfish.net/
Received on Wednesday, 21 September 2011 20:36:32 UTC

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