W3C home > Mailing lists > Public > public-webcrypto@w3.org > July 2014

[Bug 25607] Need to advise authors about security considerations

From: <bugzilla@jessica.w3.org>
Date: Sat, 12 Jul 2014 16:44:31 +0000
To: public-webcrypto@w3.org
Message-ID: <bug-25607-7213-S4qtErHuTF@http.www.w3.org/Bugs/Public/>
https://www.w3.org/Bugs/Public/show_bug.cgi?id=25607

infinity0@pwned.gg changed:

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                 CC|                            |infinity0@pwned.gg

--- Comment #29 from infinity0@pwned.gg ---
Hi, I spoke with Harry briefly recently, and he told me an overview of this
bug. Having seen how non-experts try to use cryptography libraries, I support
the move to eventually deprecate non-authenticated modes of encryption.

I have a few concrete suggestions that don't seem to have been considered
elsewhere yet:

A. Force modes like {CTR,CBC,CFB} to be paired with a MAC, by requiring the
Algorithm object to include a subfield that specifies a mac Algorithm object.
B. Put those modes in yet another module, like window.crypto.subtle.old

I don't think it is so important to avoid "creat[ing] a point in time snapshot
of a security state". This can be applied to *any* security spec that you might
care to write about. Every spec has an implicit time-context, you have to
expect future security implementors to understand this.

The alternative is to not commit to any advice about anything, instead giving
vague recommendations to "RTF existing literature", which very few application
authors will do.

"Any advice against is, implicitly, advice for" - a distinction should still be
made between "maybe-bad" and "definitely-bad".

I do think it's a good idea to have separate documentation for implementors vs
authors. No-one is in both roles, and putting both in the same document makes
it more likely important advice will cause TL;DR. For example, things like
"non-constant-time ECC curve implementations" is an implementation concern,
whereas the abuse of {CTR,CBC,CFB} mode would be a concern for application
authors.

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Received on Saturday, 12 July 2014 16:44:33 UTC

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