What evidence do auditors commonly ask for on CRY-04 Secure key management?

Key lifecycle procedure running from generation through to destruction; Key register recording owner, purpose, cryptoperiod and next rotation date; Proof that the key store operates separately from application and middleware tiers; Key compromise response instruction and any compromise event that invoked it.

What is the most common gap auditors find on CRY-04?

Keys generated on general purpose systems with no assured source of entropy

BSI C5 (121-criteria catalogue) · C5: Cryptography and Key Management

`CRY-04` Secure key management

Operate key management spanning generation, certificate issuance, activation, storage isolated from application and middleware layers, authorised retrieval, rekeying, compromise handling, withdrawal and deletion, with separate rules stated where pre-shared keys are used.

Source: BSI C5 (121-criteria catalogue), CRY-04. The statement above is our statement of the clause, read from the published text and cited so you can check it against the official text, not the instrument verbatim. Open BSI C5 (121-criteria catalogue) in the compliance library.

The edition of the catalogue is not stamped here; check the edition your attestation is issued against.

artefacts

held by a system

at each review

moderate

to go live

Key management / PKI

where the evidence lives

teal = a system already holds it · olive = produced at each review. To go live: easy when half or more of the artefacts are already held by a system, moderate from a quarter to a half, hard below a quarter.

These are the artefacts auditors commonly ask for on this requirement, our guidance rather than text from the standard. Your assessor decides what is sufficient in your context, and asks for samples across the period when a report covers one.

system holds itEvidence a system already holds

Key compromise response instruction and any compromise event that invoked it · Key management / PKI

periodic reviewEvidence produced at each review

none for this control

governing documentDocuments that govern the control

Key lifecycle procedure running from generation through to destruction · Policy repository / GRC workspace
Key register recording owner, purpose, cryptoperiod and next rotation date · Policy repository / GRC workspace
Proof that the key store operates separately from application and middleware tiers · Policy repository / GRC workspace

First move

Start with the 1 of 4 artefacts that already live in a system (Key management / PKI); keep the periodic reviews but log each one as a dated record with a named reviewer.

Common gaps auditors find

Keys generated on general purpose systems with no assured source of entropy
Rotation intervals defined on paper while expired keys stay in productive use
Pre-shared secrets circulated by mail or chat with no dedicated handling provisions

Do this for your whole sheet

Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.

Build my evidence sheet

CRY-03 Encryption of sensitive data for storage · DEV-01 Policies for the development/procurement of information systems