Re: [jose] RSA-PSS salt size

Richard Barnes <rlb@ipv.sx> Wed, 31 July 2013 16:44 UTC

Return-Path: <rlb@ipv.sx>
X-Original-To: jose@ietfa.amsl.com
Delivered-To: jose@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 9C6A521F9F9A for <jose@ietfa.amsl.com>; Wed, 31 Jul 2013 09:44:12 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.976
X-Spam-Level:
X-Spam-Status: No, score=-2.976 tagged_above=-999 required=5 tests=[AWL=-0.000, BAYES_00=-2.599, FM_FORGED_GMAIL=0.622, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id IxlUdO7oKEAB for <jose@ietfa.amsl.com>; Wed, 31 Jul 2013 09:44:07 -0700 (PDT)
Received: from mail-oa0-f46.google.com (mail-oa0-f46.google.com [209.85.219.46]) by ietfa.amsl.com (Postfix) with ESMTP id B094C21F9F8A for <jose@ietf.org>; Wed, 31 Jul 2013 09:44:07 -0700 (PDT)
Received: by mail-oa0-f46.google.com with SMTP id l10so2008886oag.33 for <jose@ietf.org>; Wed, 31 Jul 2013 09:44:07 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:x-originating-ip:in-reply-to:references:date :message-id:subject:from:to:cc:content-type:x-gm-message-state; bh=DPVz6NOs2HvXwlbD5Mfn6Fpr81YpoCh/LU4q9QGJQZw=; b=BvLySvNRe7H8AGmIH2ILk5RwTXOgdSyLXrdQAnfPCPhJjFzj4ZG5UsIUBnCmEFE8HR PnUvQSjhjkVRk5e4GFeG/Lq7vWaAAg+hYpc2/j971Jjs+NZO0RQ7y2pry+I0Vl8T62pE 5VkGSenWbP85NtTRd9v64+7zpu6wvxUSpiM1edKrPHJxwo1qBvU8QRNg8Jili43UoRKW ypbuRTw6bZeU5V2yvRxXlp+Du8D/wCAiEyyY4BRX/7hhbw1ZlLWQPCPc1BUquMkxu7Fq Rjn4OBX6sGCQ6gpu8Fo3adFuFxnrbEet0WZIrjvKwgJRCLd8di9g3Hb+9MPsgRIh9ZOs zDvA==
MIME-Version: 1.0
X-Received: by 10.60.115.199 with SMTP id jq7mr66820964oeb.19.1375289047118; Wed, 31 Jul 2013 09:44:07 -0700 (PDT)
Received: by 10.60.26.135 with HTTP; Wed, 31 Jul 2013 09:44:07 -0700 (PDT)
X-Originating-IP: [128.89.254.245]
In-Reply-To: <4E1F6AAD24975D4BA5B16804296739436B7347E3@TK5EX14MBXC284.redmond.corp.microsoft.com>
References: <4E1F6AAD24975D4BA5B16804296739436B7347E3@TK5EX14MBXC284.redmond.corp.microsoft.com>
Date: Wed, 31 Jul 2013 18:44:07 +0200
Message-ID: <CAL02cgT87Zji4hXQxq027AHJOCbToKPc1zVm2YBkr3ughaVE3Q@mail.gmail.com>
From: Richard Barnes <rlb@ipv.sx>
To: Mike Jones <Michael.Jones@microsoft.com>
Content-Type: multipart/alternative; boundary="089e0115e8e81e082b04e2d16fce"
X-Gm-Message-State: ALoCoQkLsraoEuroI4kYBBreeysqG6NkLlpEmPCgSW/sy7GWfTN9GSW968mVp5tS860Hqng1OAF5
Cc: "jose@ietf.org" <jose@ietf.org>
Subject: Re: [jose] RSA-PSS salt size
X-BeenThere: jose@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Javascript Object Signing and Encryption <jose.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/jose>, <mailto:jose-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/jose>
List-Post: <mailto:jose@ietf.org>
List-Help: <mailto:jose-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/jose>, <mailto:jose-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 31 Jul 2013 16:44:13 -0000

I agree.  Just like with EC key derivation, let's set a conservative
default value for entropy sources.


On Wed, Jul 31, 2013 at 4:26 PM, Mike Jones <Michael.Jones@microsoft.com>wrote:

>  It was pointed out to me that we failed to specify the salt size for RSA
> PSS signatures.  RFC 3447 says that “Typical salt lengths in octets are
> hLen (the length of the output of the hash function Hash) and 0.”  Having
> looked into it a bit I believe that it would be appropriate for us to
> specify that the salt length be the same as the output size of the hash
> function used.  So 256 for PS256, 384 for PS384, and 512 for PS512.****
>
> ** **
>
> Any disagreement with that choice?****
>
> ** **
>
>                                                             -- Mike****
>
> ** **
>
> _______________________________________________
> jose mailing list
> jose@ietf.org
> https://www.ietf.org/mailman/listinfo/jose
>
>