Subject: [bitcoindev] [BIP Proposal] Add BIP-0093 (Codex32) as application to BIP-0085

From: "'Ben Westgate' via Bitcoin Development Mailing List" <[email-masked]>
Date: Sun, 31 Aug 2025 15:25:47 -0700 (PDT)

Hello bitcoin-dev,

I’m Ben Westgate, a contributor interested in deterministic wallet backups 
and seed management.

Per BIP-0002, I propose listing *BIP-0093 (codex32)* 
<https://github.com/bitcoin/bips/blob/master/bip-0093.mediawiki> as an 
application of
*BIP-0085 (Deterministic Entropy from BIP32 Keychains) 
<https://github.com/bitcoin/bips/blob/master/bip-0085.mediawiki>*, similar 
to the existing BIP39 application. This allows wallets to derive codex32 
backups from BIP-0032 master keys.

*Summary* 

   - 
   
   Application number: 93'
   - Derivation path: 
   m/83696968'/93'/{hrp}'/{threshold}'/{n}'/{byte_length}'/{id0}'/{id1}'/{id2}'/{id3}'/{index}' 
   
Codex32, defined in BIP-93, is a human-readable encoding with checksumming 
and share indexing designed for SSS backups of BIP-0032 seeds. This PR 
proposes a deterministic way to generate codex32 strings using BIP-85.

*Rationale* 

   - 
   
   Mirrors the existing BIP-85 application for BIP-39.
   - 
   
   Codex32 offers error correction, hand verification, identifiers, and 
   secret sharing features compared to BIP-39.
   - 
   
   Adds a standardized way for wallets to generate codex32 backups from 
   BIP-85-derived entropy
   - 
   
   Test vectors and reference implementation are linked to in the PR.
   
*Risks and alternatives* 

   - 
   
   Wallet adoption of codex32 is still limited, though a draft PR #32652 
   <https://github.com/bitcoin/bitcoin/pull/32652?utm_source=chatgpt.com> 
   for importing codex32 strings to Bitcoin Core has support.
   - Codex32 implementers could use the BIP-85 dice application, but 
   defining a direct application improves interoperability.

PR: 
https://github.com/bitcoin/bips/compare/master...BenWestgate:bips:codex32 
<https://github.com/bitcoin/bips/compare/master...BenWestgate:bips:codex32?utm_source=chatgpt.com>

Feedback is welcome.
Best regards,
Ben Westgate

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