Root CA key ceremony

The most critical application of threshold cryptography: protecting the CA root key. Every CA compromise in history involved a single key being stolen. Threshold signing eliminates this attack vector.

Lifecycle

  1. Key ceremony: 3-of-5 participants run threshold DKG. The root key exists only as a Shamir-shared secret — never reconstructed.
  2. Operational signing: 3-of-5 quorum signs intermediate CA certs, CRLs, and OCSP responses.
  3. Annual proactive refresh: Herzberg refresh rotates shares without changing the root key. Previously compromised shares become useless.
  4. Transparency log: every signing event anchored for audit.

Quickstart

# Phase 1: key ceremony
kg = Confium::TC::Cmp20.keygen(3, 5)

# Phase 2: operational signing
sig = Confium::TC::Cmp20.sign(kg["shares"].first(3), 3, cert_body)

# Phase 3: annual refresh (see confium-tc-cmp20::refresh)

See examples/root_ca_ceremony.rb.