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Re: Request for feedback: DOMCrypt API proposal

From: Anders Rundgren <anders.rundgren@telia.com>
Date: Sun, 05 Jun 2011 09:52:29 +0200
Message-ID: <4DEB35BD.1080107@telia.com>
To: David Dahl <ddahl@mozilla.com>
CC: public-web-security@w3.org
I have a question which I brought up in the "Identity in the Browser" WS:

If you do private/secret key operations that target keys that reside
in the platform, doesn't that require a GUI like crypto.signText()?

My experiences with Microsoft's "CertEnroll" indicates that exposing
platform crypto modules to untrusted browser code is a surefire way
of getting into trouble.

I don't see that statically installed ActiveX controls and JavaScript
are any different in this respect.

Anders

On 2011-06-02 15:46, David Dahl wrote:
> Hello public-web-security members,
> 
> (I wanted to post this proposed draft spec for the DOMCrypt API ( https://wiki.mozilla.org/Privacy/Features/DOMCryptAPISpec/Latest ) to this list - if there is a more fitting mailing list, please let me know)
> 
> I recently posted this draft spec for a crypto API for browsers to the whatwg (see: http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2011-May/031741.html) and wanted to get feedback from W3C as well.
> 
> Privacy and user control on the web is of utter importance. Tracking, unauthorized user data aggregation and personal information breaches are becoming so commonplace you see a new headline almost daily. (It seems).
> 
> We need crypto APIs in browsers to allow developers to create more secure communications tools and web applications that don’t have to implicitly trust the server, among other use cases.
> 
> The DOMCrypt API is a good start, and more feedback and discussion will really help round out how all of this should work – as well as how it can work in any browser that will support such an API.
> 
> This API will provide each web browser window with a ‘cipher’ property[1] that facilitates:
> 
>     asymmetric encryption key pair generation
>     public key encryption
>     public key decryption
>     symmetric encryption
>     signature generation
>     signature verification
>     hashing
>     easy public key discovery via meta tags or an ‘addressbookentry’ tag
> 
> [1] There is a bit of discussion around adding this API to window.navigator or consolidation within window.crypto
> 
> I have created a Firefox extension that implements most of the above, and am working on an experimental patch that integrates this API into Firefox.
> 
> The project originated in an extension I wrote, the home page is here: http://domcrypt.org
> 
> The source code for the extension is here: https://github.com/daviddahl/domcrypt
> 
> The Mozilla bugs are here:
> 
> https://bugzilla.mozilla.org/show_bug.cgi?id=649154
> https://bugzilla.mozilla.org/show_bug.cgi?id=657432
> 
> Firefox "feature wiki page": https://wiki.mozilla.org/Privacy/Features/DOMCryptAPI
> 
> You can test the API by installing the extension hosted at domcrypt.org, and going to http://domcrypt.org
> 
> A recent blog post updating all of this is posted here: http://monocleglobe..wordpress.com/2011/06/01/domcrypt-update-2011-06-01/
> 
> The API:
> 
> window.cipher = {
>  // Public Key API
>  pk: {
>    set algorithm(algorithm){ },
>    get algorithm(){ },
> 
>   // Generate a keypair and then execute the callback function
>   generateKeypair: function ( function callback( aPublicKey ) { } ) {  },
> 
>   // encrypt a plainText
>   encrypt: function ( plainText, function callback (cipherMessageObject) ) {  } ) {  },
> 
>   // decrypt a cipherMessage
>   decrypt: function ( cipherMessageObject, function callback ( plainText ) { } ) {  },
> 
>   // sign a message
>   sign: function ( plainText, function callback ( signature ) { } ) {  },
> 
>   // verify a signature
>   verify: function ( signature, plainText, function callback ( boolean ) { } ) {  },
> 
>   // get the JSON cipherAddressbook
>   get addressbook() {},
> 
>   // make changes to the addressbook
>   saveAddressbook: function (JSONObject, function callback ( addresssbook ) { }) {  }
>   },
> 
>   // Symmetric Crypto API
>   sym: {
>   get algorithm(),
>   set algorithm(algorithm),
> 
>   // create a new symmetric key
>   generateKey: function (function callback ( key ){ }) {  },
> 
>   // encrypt some data
>   encrypt: function (plainText, key, function callback( cipherText ){ }) {  },
> 
>   // decrypt some data
>   decrypt: function (cipherText, key, function callback( plainText ) { }) {  },
>   },
> 
>   // hashing
>   hash: {
>     SHA256: function (function callback (hash){}) {  }
>   }
> }
> 
> Your feedback and criticism will be invaluable.
> 
> Best regards,
> 
> David Dahl
> 
> Firefox Engineer, Mozilla Corp.
> 
> 
> 
> 
Received on Sunday, 5 June 2011 07:53:26 GMT

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