Re: [rtcweb] Which hashes are valid for the fingerprint attribute?

Inaki,

I checked a little bit, following our previous exchange.

There was a thread back in november last year in discuss-webrtc (how to
specify desired hash function(s) (sha-1, sha-256, sha-512) for DTLS-SRTP?)

Justin said "Chrome supports various hash functions in the remote
description (SHA-1, 256, 512). Local description currently only
supports SHA-256,
no plans to change that (although we will probably support longer hashes in
the future for hash agility). Asymmetric hash functions should not be an
issue. If multiple fingerprints are specified in the remote description, I
think Chrome will only use the first one."

then in ORTC there was this thread in april:
"Issue 64: Section 2.5.1 Fingerprint attribute"
in which bernard proposed:
"
dictionary RTCDtlsParameters {
    RTCDtlsRole                  role = "auto";
    sequence<RTCDtlsFingerprint> fingerprint;
};
dictionary RTCDtlsFingerprint {
    RTCDtlsCertificateHashAlgorithm algorithm;
    ArrayBuffer                     value;
};
enum RTCDtlsCertificateHashAlgorithm {
    "sha-1",
    "sha-224",
    "sha-256",
    "sha-384",
    "sha-512"
};
"

On Fri, Jul 11, 2014 at 8:26 PM, Iñaki Baz Castillo <ibc@aliax.net> wrote:

> Hi,
>
> Hi, RFC 5763 and RFC 5764 (DTLS-SRTP) do not mandate a specific hash
> for the fingerprint attribute in the SDP. RFC 5763 refers to RFC 4572
> "Connection-Oriented Media Transport over TLS in SDP”. Its section 5
> clearly opens the door to multiple hash functions:
>
>    hash-func    =  "sha-1" / "sha-224" / "sha-256" /
>                          "sha-384" / "sha-512" /
>                          "md5" / "md2" / token
>                          ; Additional hash functions can only come
>                          ; from updates to RFC 3279
>
>
> I'm pretty sure that WebRTC implementations are not ready for all
> those hash functions. Is there any WebRTC related draft constraining
> the hash functions that can be used?
>
> Thanks a lot.
>
>
> PS: Not sure if this question should be placed here or in public-webrtc ML.
>
> --
> Iñaki Baz Castillo
> <ibc@aliax.net>
>
> _______________________________________________
> rtcweb mailing list
> rtcweb@ietf.org
> https://www.ietf.org/mailman/listinfo/rtcweb
>

-- 
Alex. Gouaillard, PhD, PhD, MBA
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