正解:D
SHA-2 is a family of hash functions that includes SHA-256, SHA-384, and SHA-512. SHA-2 is part of the Next Generation Encryption (NGE) suite of cryptographic algorithms that Cisco recommends for strong security and good performance. SHA-2 is believed to be quantum-computer resistant, meaning that it would not be easily broken by a hypothetical quantum-computer. SHA-2 is also more secure than older hash functions such as MD5 and SHA-1, which have been shown to have weaknesses and collisions. SHA-2 is widely used in various protocols and functions, such as digital signatures, integrity verification, and key derivation. References: 1
https://sec.cloudapps.cisco.com/security/center/resources/next_generation_cryptography
https://www.cisco.com/c/en/us/support/docs/security-vpn/ipsec-negotiation-ike-protocols/116055-technote- ios-crypto.html