UTF-8 Hashing

[starryrendezv...@gmail.com]

I got a bug filed for my extension, since I am using the native hash
functionalities right from the XPCOM (@mozilla.org/security/hash;1)
without any code from me between it, I wonder how to solve this:

md5 hash a UTF-8 encoded string:

"您好"(it means "hello" in Chinese), it yields a different result from
python hashlib and unix md5sum when being processed by the XPCOM
object  @mozilla.org/security/hash;1

Any thought how to go about this?
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Re: UTF-8 Hashing

[starryrendezv...@gmail.com]

If it helps, here is the code I currently utilize;

hash: function(str,method) {

   var hash_engine = Components.classes["@mozilla.org/security/hash;
1"].createInstance().QueryInterface
(Components.interfaces.nsICryptoHash);

switch(method) {
case 'MD5':
hash_engine.init(hash_engine.MD5);
break;
case 'SHA1':
hash_engine.init(hash_engine.SHA1);
break;
case 'SHA256':
hash_engine.init(hash_engine.SHA256);
break;
}

   var charcodes = [];
   for (var i = 0; i < str.length; i++){
 charcodes.push(str.charCodeAt(i));
   }
   hash_engine.update(charcodes, str.length);
   return TOOLS.convert('bin2hex',hash_engine.finish(false));
},
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Re: UTF-8 Hashing

[starryrendezv...@gmail.com]

On Apr 23, 3:39 pm, Jean-Marc Desperrier  wrote:
> Nelson B Bolyard wrote:
> > Is that python code?  I thought it was JavaScript.
>
> Yes, you're right, I had a really too quick look at it :-)

On a second thought, I just had a look at this page:
https://developer.mozilla.org/En/NsICryptoHash
Where it states that one must use the scriptable unicode converter
first to get bytes back that were UTF-8 encoded:

var converter =
Components.classes["@mozilla.org/intl/scriptableunicodeconverter"].
createInstance(Components.interfaces.nsIScriptableUnicodeConverter);

// we use UTF-8 here, you can choose other encodings.
converter.charset = "UTF-8";

I guess that's what I missed?

/rvdh
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Re: UTF-8 Hashing

[starryrendezv...@gmail.com]

Right, this seems to work very well. I consider it solved.


Here is the corrected code:

hash: function(str,method) {

var converter = Components.classes["@mozilla.org/intl/
scriptableunicodeconverter"].createInstance
(Components.interfaces.nsIScriptableUnicodeConverter);
converter.charset = "UTF-8";
var result = {};
var data = converter.convertToByteArray(str, result);
var hash_engine = Components.classes["@mozilla.org/security/hash;
1"].createInstance().QueryInterface
(Components.interfaces.nsICryptoHash);

switch(method) {
case 'MD5':
hash_engine.init(hash_engine.MD5);
break;
case 'SHA1':
hash_engine.init(hash_engine.SHA1);
break;
case 'SHA256':
hash_engine.init(hash_engine.SHA256);
break;
}

   hash_engine.update(data, result.value);
   return TOOLS.convert('bin2hex',hash_engine.finish(false));
},
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