Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 56F13904 for ; Wed, 29 Mar 2017 10:07:56 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from blaine.gmane.org (unknown [195.159.176.226]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id CFD7586 for ; Wed, 29 Mar 2017 10:07:54 +0000 (UTC) Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1ctAW1-0008VY-Jv for bitcoin-dev@lists.linuxfoundation.org; Wed, 29 Mar 2017 12:07:45 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: bitcoin-dev@lists.linuxfoundation.org From: Andreas Schildbach Date: Wed, 29 Mar 2017 12:07:40 +0200 Message-ID: References: <20170321191454.GA17834@savin.petertodd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@blaine.gmane.org User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 In-Reply-To: <20170321191454.GA17834@savin.petertodd.org> X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00,DKIM_ADSP_ALL, RDNS_NONE autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] A BIP proposal for segwit addresses X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Mar 2017 10:07:56 -0000 On 03/21/2017 08:14 PM, Peter Todd via bitcoin-dev wrote: > On Tue, Mar 21, 2017 at 05:16:30PM +0100, Andreas Schildbach via bitcoin-dev wrote: >> Why use Base 32 when the QR code alphanumeric mode allows 44 characters? >> In Bitcoin Wallet, I use Base 43 (alphabet: >> "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ$*+-./:") for most efficient QR >> code encoding. I only leave out the space character because it gets >> replaced by "+" in URLs. > > Doing that only makes addresses a few % shorter, at the cost of significant > downsides. For example, not everyone knows what those additional characters > are called, particularly for non-English-speaking users. Non-alphanumeric > characters also complicate using the addresses in a variety of contexts ('/' > in particularly isn't valid in filenames). I'm not convinced that transmitting addresses via voice should be a usecase to target at. I don't understand your comment about non-english speaking users. Obviously they cannot voice-communicate at all with only-english-speaking users, so there is no need to communicate voice-communicate addresses between them. Addresses in QR codes, addresses in URLs and addresses in NFC NDEF messages are the three most used forms. Speaking of URLs, actually Base 32 (as well as Base 43) makes QR codes *bigger* because due to the characters used for URL parameters (?&=) those QR codes are locked to binary mode. To make them shorter, we'd need to use something like "Base 64url" (or ideally Base 94 -- all printable ASCII characters).