Siemens Siemens AKAYLA, Inc. sn3rd When an end entity includes attestation statements in a Certificate Signing Request (CSR), the freshness of the conveyed Evidence often needs to be established. A common mechanism is a nonce that is obtained from a Relying Party or Verifier and included by the Attester in the Evidence. This document specifies how an end entity requests such an attestation freshness nonce from an RA/CA when using certificate lifecycle management protocols. It defines message formats and protocol bindings for the conveyance of nonce request and response messages in the Certificate Management Protocol (CMP), Enrollment over Secure Transport (EST), and Certificate Management over CMS (CMC), including optional type-specific information needed to produce fresh Evidence for inclusion in a CSR.