Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 73FC7DBC for ; Wed, 13 Jun 2018 14:58:55 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-io0-f179.google.com (mail-io0-f179.google.com [209.85.223.179]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 1A4AD681 for ; Wed, 13 Jun 2018 14:58:55 +0000 (UTC) Received: by mail-io0-f179.google.com with SMTP id l25-v6so3719809ioh.12 for ; Wed, 13 Jun 2018 07:58:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=blockstream.io; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=tv/ZUPxDHNIABWMycZ4Rn2X+4yg/Vv7HcGbqIvRt1mU=; b=tbVJENCxP/jvUKUVv9vyMbodJ+AsZsmrZlsfHCk/JMBeFXjC6ju5BxBowbhLDY4Epc upZazVI2lJHtwdwoCdYDAQlMa9UHTP318LP2kmlGsLSju2sLMY8wTd24vgmcO/9trqK1 6zqZwpKzlwBGVHK/iHN0TpcLu4HViLqo59eMU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=tv/ZUPxDHNIABWMycZ4Rn2X+4yg/Vv7HcGbqIvRt1mU=; b=lhnavj3ghoQW8d4SIq+kiHgJHboUX+xgi9E2SPgWMYXTcNBVWLiLGWXOLXNVwO+Kur g3AGsWcwPDB6J/mTSdy6A7IwkHox8T2NVQyHeLcm8ROb+2Xo5HSK8AtZ/ZRwtAdyeAQD yuKU2a71PZ/5HFRwMLVZ+5odayEpJDKSfFIfGD5C7SHPmXNa74gNxA3we7est+/jYH63 B+VsVVKz8bLPvOTETteYewYIIExm+gx2D82oCqDRs6FdEVYu1wzfb5aewM5dF9K6U8D8 gS+8Q4OkV+fjNCZ+B5eUzXSwRa6Fn06Yvd2neLumW38w8OYpf1cvhrABR7m/Na99p9vR WIOw== X-Gm-Message-State: APt69E27j01JK1DuaSj8KMHKU0QTBqdFAFA7T56CBcm/GLBW++vMCuPd fF8A0/E0fl5xPx0eavYljPs2KLZIY5NVWRFEZTDrzEVC X-Google-Smtp-Source: ADUXVKKJlTN5JeOXZmFC09aYRz5bffsPIFGYkNKhx37cmdXUo5/yaSg+txY4o37/iDs/V3nZNyge7qTHzUX/EqszmjM= X-Received: by 2002:a6b:9ec7:: with SMTP id h190-v6mr5012932ioe.185.1528901934300; Wed, 13 Jun 2018 07:58:54 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a02:1253:0:0:0:0:0 with HTTP; Wed, 13 Jun 2018 07:58:33 -0700 (PDT) In-Reply-To: <03557E21-8CFC-4822-8494-F4A78E23860B@jonasschnelli.ch> References: <03557E21-8CFC-4822-8494-F4A78E23860B@jonasschnelli.ch> From: "Russell O'Connor" Date: Wed, 13 Jun 2018 10:58:33 -0400 Message-ID: To: Jonas Schnelli , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary="000000000000b0dcfb056e873858" X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HTML_MESSAGE, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] New serialization/encoding format for key material 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, 13 Jun 2018 14:58:55 -0000 --000000000000b0dcfb056e873858 Content-Type: text/plain; charset="UTF-8" On Tue, May 29, 2018 at 5:13 AM, Jonas Schnelli via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > Hi > > If 520 bits are present, first 256 bits are the BIP32 chain code, to > second 264 > bits (33 bytes) define the public key (according to BIP32) > In a 33 byte compressed public key, only 1 bit from the first byte conveys information. The other 7 bits can be discarded. This will allow you to reduce the bech32 encoded result by one character. --000000000000b0dcfb056e873858 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On T= ue, May 29, 2018 at 5:13 AM, Jonas Schnelli via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
Hi

If 520 bits are present, first 2= 56 bits are the BIP32 chain code, to second 264=C2=A0
bits (33 by= tes) define the public key (according to BIP32)

In a 33 byte compressed public key, only 1 bit from the f= irst byte conveys information.=C2=A0 The other 7 bits can be discarded.=C2= =A0 This will allow you to reduce the bech32 encoded result by one characte= r.
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