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Re: [MMUSIC] 4572 update: forbid weak hashes?

Christer Holmberg <christer.holmberg@ericsson.com> Thu, 07 April 2016 13:35 UTC

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From: Christer Holmberg <christer.holmberg@ericsson.com>
To: Jonathan Lennox <jonathan@vidyo.com>, mmusic <mmusic@ietf.org>
Thread-Topic: 4572 update: forbid weak hashes?
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Date: Thu, 07 Apr 2016 13:35:07 +0000
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Subject: Re: [MMUSIC] 4572 update: forbid weak hashes?
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Hi Jonathan,

>For the RFC 4572 update, I think we should add that receivers MUST NOT match on fingerprints >computed with weak hashes, and senders SHOULD NOT send them.
>
>If we do this, it removes some of the questions about “do you need to verify a fingerprint for every >hash algorithm, or only one.”

What about saying that one MUST match on the strongest hash received? 

Then, if you only receive a weak hash, isn't it still better to match than doing nothing?

>Weak hashes definitely include MD2 and MD5.  I guess we still want SHA-1 to be supported, though?

I'll let others decide on whether we still want to allow SHA-1, but the suggestion is to make SHA-256 the preferred one.

Regards,

Christer
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