# certs/

## bambu_ca2.pem

Bambu Lab's shared root CA ("BBL CA2 RSA") used to verify a printer's LAN-mode
MQTTS (port 8883) certificate. Current-generation Bambu printers present a
certificate signed by (a chain rooted at) this CA — trust this one file
instead of fetching/pinning a certificate per printer.

- Source: https://github.com/bambulab/BambuStudio/blob/master/resources/cert/printer.cer
- Fetched: 2026-08-28
- SHA-256 fingerprint: `E9:8F:19:57:8B:3F:12:4A:CE:6B:8A:24:7F:FE:DA:52:DC:99:C8:9F:D4:E7:D2:0C:82:82:99:77:B7:F3:35:02`
- Verified with `openssl x509 -noout -text`: self-signed (`Issuer == Subject`),
  `Basic Constraints: CA:TRUE`, `Key Usage: Certificate Sign, CRL Sign` — a
  genuine root CA, not a per-device leaf certificate. Valid until 2050.

The "CA2" name implies there was a CA1 generation before it — some
older printers/firmware may not chain to this root and need their own
certificate instead. `CONTINUUM_BAMBU_CA_CERT_PATH` (see `.env.example`)
overrides this default with a specific file for exactly that case.

If a printer's connection ever fails certificate verification against this
file, re-fetch from the source URL above (BambuStudio ships whatever the
current fleet needs) and update the fingerprint here.