command on your ASA to find the serial number used for licensing (note: this may differ from the chassis serial number). Use the License Portal: Log in to the Cisco License Registration portal and enter your PAK and device serial number. Activate via CLI: Once received via email, apply the key using the command: activation-key Special Licenses: Certain features, such as Strong Encryption (3DES/AES)
The key is stored in a hidden partition of the ASA’s flash memory, not in the standard configuration file. Cisco Press Legitimate Ways to Obtain Keys
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: