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Date: Mon, 7 Apr 2014 19:07:45 -0700
Message-ID: <CAAS2fgSfiYwD-M7+k65JF0Kjeod1zEiPcxPN1iDBHLzYV7UQyA@mail.gmail.com>
From: Gregory Maxwell <gmaxwell@gmail.com>
To: Matt Whitlock <bip@mattwhitlock.name>
Content-Type: text/plain; charset=UTF-8
Cc: bitcoin-development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Presenting a BIP for Shamir's Secret
 Sharing of Bitcoin private keys
Precedence: list

On Mon, Apr 7, 2014 at 6:46 PM, Matt Whitlock <bip@mattwhitlock.name> wrote:
> On Monday, 7 April 2014, at 5:38 pm, Gregory Maxwell wrote:
>> On Mon, Apr 7, 2014 at 5:33 PM, Nikita Schmidt
>> <nikita@megiontechnologies.com> wrote:
>> > Regarding the choice of fields, any implementation of this BIP will
>> > need big integer arithmetic to do base-58 anyway.
>> Nah, it doesn't. E.g.
>> https://gitorious.org/bitcoin/libblkmaker/source/eb33f9c8e441ffef457a79d76ceed1ea20ab3059:base58.c
> That only *decodes* Base58Check. It has no encode function, which would require biginteger division.

Yes thats only a decode but the same process (long division with
manual carries) works just fine the other way. There is absolutely no
need to use big integers for this.