W3C home > Mailing lists > Public > public-webcrypto@w3.org > January 2013

Re: An initial editor's draft: high-level API

From: Ryan Sleevi <sleevi@google.com>
Date: Mon, 28 Jan 2013 10:33:20 -0800
Message-ID: <CACvaWvb9OXUDjYP6djJTTrHA59U-3GzM=CznpixNu4Ow9wYvzg@mail.gmail.com>
To: David Dahl <ddahl@mozilla.com>
Cc: public-webcrypto <public-webcrypto@w3.org>
On Mon, Jan 28, 2013 at 7:50 AM, David Dahl <ddahl@mozilla.com> wrote:
> Hello All,
> An initial high-level API draft is here: https://dvcs.w3.org/hg/webcrypto-highlevel/raw-file/tip/Overview.html
> Naturally, this draft is missing a few things, details, etc. Some early feedback indicates that "sign" and "verify" are redundant with encryptAndSign and verifyAndDecrypt.
> The object and method naming needs work as well. Your feedback and criticism is eagerly awaited.

I am having a hard time understanding what makes this proposal
"high-level", based on your specification:

1) You do not specify what the values returned are to callbacks. For
example, does .onProtect return a JWE-JS on onProtectComplete?
2) Your callbacks do not seem to permit multiple parallel operations:

window.crypto.highlevel.onProtectComplete = function(...) { }
window.crypto.highlevel.onProtectError = function(...) { }
window.crypto.highlevel.protect("a", "JWA-ALG-HERE");
window.crypto.highlevel.protect("b", "BAD-JWA-ALG-HERE");

In onProtectComplete and onProtectError, how do I know which was the
good message and which was the bad message? Am I relying on the
ordering of the calls?

3) This does not seem to actually be high-level, in that it still
forces the caller to make decisions about algorithms throughout the
API, a point which I understood the high level was intentionally
intending to entirely abstract. You do not, for example, want to
encourage developers to use PKCS#1 v1.5 in new applications, but
that's effectively what this API does (as PKCS#1 v1.5 is the only
REQUIRED to implement in JOSE). What is the motivation for this, and
is this necessary? Isn't it better to hide these security parameters
entirely, and let the user agent make the most informed security
decision based on the security policy of the browser?
4) You've specified a hash interface, but this seems entirely
redundant with the existing specification, which already permits JOSE
5) onProtect takes arguments in the form (aPlaintext, aJOSEAlg), but
onUnprotect takes them in (aKeyID, aPlaintext).
  a) Shouldn't onUnprotect's argument be named aCiphertext
  b) Shouldn't the order of the arguments be symmetrical between the the API
6) Same for the lack of symmetry between sign()/verify()
7) You make use of DOMString in the following methods:
  a) encryptAndSign (aPlainText)
  b) protect (aPlaintext)
  c) unprotect (aPlaintext - see 5)
  d) sign (aClearData)
  e) verify (aDataToVerify)
How is this data supposed to be canonicalized? How is arbitrary binary
data supposed to be encoded? What about decoded?
Received on Monday, 28 January 2013 18:33:48 UTC

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