CASA-VN-000340 - The Cisco ASA VPN gateway must use cryptographic algorithms approved by NSA to protect NSS when transporting classified traffic across an unclassified network - crypto map


Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The VPN gateway must implement cryptographic modules adhering to the higher standards approved by the Federal Government since this provides assurance they have been tested and validated.

NIST cryptographic algorithms are approved by NSA to protect NSS. Based on an analysis of the impact of quantum computing, cryptographic algorithms specified by CNSSP-15 and approved for use in products in the CSfC program have been changed to more stringent protocols and configured with increased bit sizes and other secure characteristics to protect against quantum computing threats. The Commercial National Security Algorithm Suite (CNSA Suite) replaces Suite B.


Configure the VPN gateway to use cryptography that is compliant with CSNA/CNSSP-15 parameters when transporting classified traffic across an unclassified network as shown in the example below.

Step 1: Configure the IKE Phase 1.

ASA2(config)# crypto ikev2 policy 2
ASA2(config-ikev2-policy)# encryption aes-256
ASA2(config-ikev2-policy)# integrity null
ASA2(config-ikev2-policy)# group 20
ASA2(config-ikev2-policy)# prf sha384
ASA2(config-ikev2-policy)# exit

Step 2: Configure the IPsec proposal for AES 256 and apply to a crypto map as shown in the example below.

ASA2(config-ipsec-proposal)# protocol esp encryption aes-256
ASA2(config-ipsec-proposal)# exit
ASA2(config)# crypto map CSNA_MAP 10 set ikev2 ipsec-proposal AES-256
ASA2(config)# end

See Also

Item Details


References: 800-53|SC-13, CAT|I, CCI|CCI-002450, Rule-ID|SV-239962r878134_rule, STIG-ID|CASA-VN-000340, Vuln-ID|V-239962

Plugin: Cisco

Control ID: 117055a3f3bfb019ca10afb417a1e81b82307e46b9f4c2ed50ff9b082678a1f1