Module bch 

BIP 93 codex32 BCH primitives for HRP "ms" (regular code only).

Vendored from md-codec’s structure at the v0.34.0 promotion (descriptor-mnemonic commit 94069ea) per plan §2.B.2 / D22. ms1 strings are all regular-code length per consts::VALID_STR_LENGTHS, so the long-code primitives are intentionally absent (mk-codec carries the long-code variants).

All public per plan D22 (no pub(crate) half-private items in ms-codec): the downstream bch_decode module (B.4) re-declares the 3 internal consts locally per the Q3 lock — they stay bare-private here.

The MS_REGULAR_CONST value is byte-exact with the toolkit’s vendored copy at mnemonic-toolkit/crates/mnemonic-toolkit/src/repair.rs:42 per Phase B.0 (e) cross-check. The toolkit’s v0.23.0 migration (Phase B.7) deletes its local copy and delegates to this crate.

Constants

GEN_REGULAR

BCH(93,80,8) generator polynomial coefficients (5 × 65-bit).

MS_REGULAR_CONST

MS-domain target residue: codex32’s “SECRETSHARE32” Fe-vec packed in big-endian 5-bit chunks (the natural u128 representation that polymod_run produces for a valid ms1 input).

Functions

bch_create_checksum_regular

13-symbol regular-code BCH checksum over hrp_expand(hrp) || data || [0; 13].

bch_verify_regular

Verify a regular-code BCH checksum over the data-part-with-checksum.

hrp_expand

BIP 173-style HRP expansion: [c >> 5 for c in hrp] ++ [0] ++ [c & 31 for c in hrp].

polymod_run

Run the BCH polymod over values starting from the BIP-93 initial residue.