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Handling of CryptoOperationData needs to be defined

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Wed, 23 Apr 2014 15:40:59 -0400
Message-ID: <5358174B.3050801@mit.edu>
To: "public-webcrypto@w3.org" <public-webcrypto@w3.org>
As far as I can tell, nothing actually defines the handling of 
CryptoOperationData arguments.

For example, looking at 
https://dvcs.w3.org/hg/webcrypto-api/raw-file/tip/spec/Overview.html#dfn-SubtleCrypto-method-encrypt 
it just says:

   Let ciphertext be the result of performing the encrypt operation
   specified by normalizedAlgorithm using algorithm and key and with
   data as plaintext.

but nothing ever defines the type of "plaintext" here.  I assume it's 
meant to be some sort of byte array, right?

If so, the following need to be clearly defined:

1)  How do extract a byte array from an ArrayBufferView.  Presumably 
this is a matter of looking at the underlying buffer and taking 
byteLength bytes starting at byteOffset.  And presumably this uses the 
canonical getters for those properties, not whatever is on the prototype 
(so the [[ViewedArrayBuffer]], [[ByteLength]], and [[ByteOffset]] 
internal slots of the object).  Note that at least one implementor just 
used all the bytes of the underlying ArrayBuffer instead, so this 
clearly does need defining.

2) The exact point when the snapshot of the data is taken.  This 
matters, because the data is not immutable.  Presumably there's some 
sort of data copy before step 3 of 
https://dvcs.w3.org/hg/webcrypto-api/raw-file/tip/spec/Overview.html#dfn-SubtleCrypto-method-encrypt 
for example?

-Boris
Received on Wednesday, 23 April 2014 19:41:36 UTC

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