Re: AES CFB input parameter "s"

I haven't heard any implementation movement on CFB.

If using PKCS#11, only 8-bit, 64-bit, and 128-bit are defined mechanisms.
SP800-38a only provides vectors for 1, 8, 128.

AFAICT, CNG supports CFB8 and CFB128 with AES. CFB128 isn't until Win8.

OS X only supports CFB8 from what I can tell (at least, via the
CommonCrypto interface being used to implement in WebKit)
On Feb 14, 2014 3:04 PM, "Mark Watson" <watsonm@netflix.com> wrote:

> All,
>
> Apologies in advance if this has been discussed before, or has a
> well-known answer.
>
> According to NIST SP800-38A [1] Section 6.3 which we reference for AES
> CFB, the input parameters to the encrypt/decrypt operations consist of an
> IV, the plaintext / ciphertext (respectively) and an additional parameter,
> s, which takes a value between 1 and 128, inclusive.
>
> What values of this shall we support in WebCrypto ?
>
> I assume that if we wish to support more than one value, then we must add
> a property to AesCfbParams for this.
>
> ...Mark
>
> [1] http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf
>