Cisco does not provide a standalone "activation key generator" for public use. Instead,
Cisco uses a proprietary system where each activation key is an encoded 160-bit string tied specifically to a hardware unit's serial number. Tied to Serial Number: cisco asa activation key generator
Using third-party "key generators" found on the internet is strongly discouraged. Such tools often distribute malware or produce invalid keys that can lead to device instability, loss of official Cisco Support Cisco does not provide a standalone "activation key