From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WXJyk-0000vE-Vj for bitcoin-development@lists.sourceforge.net; Tue, 08 Apr 2014 00:33:31 +0000 X-ACL-Warn: Received: from mail-qa0-f53.google.com ([209.85.216.53]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WXJyj-0004Yt-UZ for bitcoin-development@lists.sourceforge.net; Tue, 08 Apr 2014 00:33:30 +0000 Received: by mail-qa0-f53.google.com with SMTP id w8so187743qac.40 for ; Mon, 07 Apr 2014 17:33:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type; bh=JglUp0oUu2Ajd7jDjT0dPbeUBnzAvKIFcV8AmQEHFN8=; b=j4WezM9Qds6uup7OoqViJBl55ecXHUkwF1k8d1H8oXahroQeEkT4esn9pUHPszQrsy Bmmm4jqKRusrmM3CRPhMMybwJqO3aj0xO2Ki6gDAq4OcJ6Ntph1mDb6UY2LWcapeTI3I e04gP43HNrkxoi75RmYemd9I78WZx3Yfv7eYzrjFZufRHSX2JOc1Ufb8vXzSSyBonOEy oP6gzRCZ6URPzAr0KZDPeC4A2AWF3wq/iJHDv0kESUD8tcIFo3+5j3V9GDaTqghXPCY0 /I7UEPae4p8Q1sY4ShuPsifc+YrpFwpOoTMfs62HlDYy6LGmwJa+h0DxBiiIYXMcTsRI H3kQ== X-Gm-Message-State: ALoCoQmpoWpANrXZDlefRjFhaj6JMEZFOmxAj2huazVCqehWvIVKj/saeH374AAZv0tvknUg31Hu X-Received: by 10.140.95.8 with SMTP id h8mr688138qge.2.1396917204073; Mon, 07 Apr 2014 17:33:24 -0700 (PDT) MIME-Version: 1.0 Received: by 10.96.124.10 with HTTP; Mon, 7 Apr 2014 17:33:04 -0700 (PDT) X-Originating-IP: [2001:770:14a:0:6157:74aa:76eb:47ee] In-Reply-To: <1529077.7WHAYP4Dpn@crushinator> References: <3837746.jqWvB0Uxrs@crushinator> <1529077.7WHAYP4Dpn@crushinator> From: Nikita Schmidt Date: Tue, 8 Apr 2014 04:33:04 +0400 Message-ID: To: Matt Whitlock Content-Type: text/plain; charset=ISO-8859-1 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. X-Headers-End: 1WXJyj-0004Yt-UZ Cc: bitcoin-development Subject: Re: [Bitcoin-development] Presenting a BIP for Shamir's Secret Sharing of Bitcoin private keys X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Apr 2014 00:33:31 -0000 > > I'd be fine with changing the key fingerprint algorithm to something else. Do you like CRC16? > I like CRC16. Do you intend to use it in conjunction with a cryptographic hash? Regarding the choice of fields, any implementation of this BIP will need big integer arithmetic to do base-58 anyway. The operations required for SSS are nearly the same as for base-58 and can probably be done by the same subset of the chosen bignum library. So in fact using GF(2^8) will add complexity to both the BIP and its implementations. However, the maths in GF(2^8) is so simple that this additional complexity can be considered negligible. As a co-author of a bitcoin application running on a real microcontroller (not the sort of big-iron thing Trezor runs on), I was also going to implement my SSS over a 256-bit prime field. (I am not going into 512-bit master seeds at this time.) Uniform processing of secrets of any size (instead of using different primes for different cases) is a valid argument in favour of GF(2^8), though. I have no preference one way or another.