Re: [rtcweb] Areas of security concern

John Mattsson <> Wed, 12 March 2014 09:54 UTC

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From: John Mattsson <>
To: Watson Ladd <>, "" <>
Thread-Topic: [rtcweb] Areas of security concern
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Date: Wed, 12 Mar 2014 09:54:05 +0000
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Subject: Re: [rtcweb] Areas of security concern
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From: Watson Ladd <<>>
Date: Wednesday 12 March 2014 05:11
To: "<>" <<>>
Subject: [rtcweb] Areas of security concern

Dear all,
I've jotted down the following notes when reading the drafts from here and the W3C as potential problem areas. Maybe there are things I've missed in the drafts that address them, but I think they are still worth thinking about. Some of these are more W3C, but we seem to be in charge of the security. These issues vary widely in seriousness. One of them is a demonstrated break of confidentiality, while several are open questions about how we communicate to users.


Problem 4: HMAC-SHA1 in SRTP

>If I've chased the chain of references correctly this is the sole MAC provided.

John: Yes this is correct, (But AES-GCM and AES-CCM should  be available before WebRTC)

>Is it okay? I have no idea: SHA-1 has been significantly weakened in recent years.

John: This is ok. While SHA-1 itself is weak and should not be used for signatures, there are no attacks on HMAC-SHA-1.
NIST current recommendations say that HMAC-SHA-1 is good for use beyond 2030 (<> )