Module cert 

Certificates (W4; docs/rhdl_ubft-view-change.md): q = f + 1 signature shares from distinct replicas over one exact key (role, view, instance, digest).

Two encodings are fixed here, as kernels, so hardware and tests agree:

• value_block: the 128-byte SHA-512 input naming a value, "RUB2-VAL" ‖ session ‖ instance ‖ len ‖ 0^8 ‖ value, zero past len. The value digest d is its first 32 bytes. The session is inside d, so a share never transfers between runs.
• share_context: the 48 signed bytes (sign layout v2): "RUB2" ‖ role ‖ 0 0 0 ‖ view ‖ instance ‖ d. View and instance are full 32-bit fields (upstream packs a 16-bit view into the index, UE-C7), and the role separates prepare shares from history shares.

Modules

collector

Share collector: a certificate is q verified shares from distinct replicas over one exact key (docs/rhdl_ubft-view-change.md).

Constants

ROLE_HISTORY

Role byte of a sealed-history share.

ROLE_PREPARE

Role byte of a prepare (certify) share.

VAL_DOMAIN

"RUB2-VAL" as a little-endian word.

Functions

share_context

The 48 signed bytes of a share, as six little-endian words.

value_block

The 128-byte value-digest input as 16 big-endian SHA-512 words.

value_digest

The value digest from a finished SHA-512 state: bytes 0..32 as little-endian words.