This read-write integer from 0 to 8784 sets, in hours, how often encryption keys are renewed system-wide, with a default of 24 hours and 0 meaning renewal is disabled entirely. This is a direct security-versus-overhead tradeoff: shorter periods limit how long a compromised key stays useful, while setting it to 0 stops key rotation altogether, weakening the system's encryption posture. For example, an operator tightening security after a suspected key-compromise incident might lower hcxKeyRenewalPeriod from the default 24 hours to force more frequent rekeying across all served STUs.