show version | include Encryption Correct output: Encryption hardware device : Cisco ASA Crypto (AES-256) If you mistakenly boot k8 , you will see in logs:
%ASA-3-713903: Encryption strength is insufficient for IKEv2 policy Reload with k9 image. Final Recommendation: Delete asa9-14-4-smp-k8.bin from your flash and only use k9 images for any ASA running software 9.1 or later. If you found this file on Cisco’s download portal, report it as likely a mislabeled legacy build. asa9-14-4-smp-k8.bin
To verify encryption strength on your current ASA: show version | include Encryption Correct output: Encryption