2015年5月25日 · ESP can authenticate the PUBLIC IP in Tunnel mode. That still has nothing to do with non-repudiation, which means - the sender cannot deny that he sent the message/traffic. In case of IPsec there's no way to prove that, e.g., the recipient didn't share the session (SA) keys, or didn't forge the traffic himself (e.g., by colluding with the ISP ...

2012年6月10日 · You need ESP for that (in the IPsec context). AH may be useful in situations where integrity is important but not confidentiality, or where confidentiality through ESP would be too expensive (depending on the computational overhead of encryption, which can be high if the involved hardware is especially feeble).

2017年1月24日 · Thus if AH is used in a transport mode, in conjunction with ESP, AH SHOULD appear as the first header after IP, prior to the appearance of ESP. In that context, AH is applied to the ciphertext output of ESP. In contrast, for tunnel mode SAs, one can imagine uses for various orderings of AH and ESP.

2017年7月12日 · The problem is IPsec tunnel mode, which uses the ESP protocol. ESP doesn't work with NAT for two reasons: ESP creates a checksum covering the whole packet, including the addresses. If the NAT changes the addresses, the integrity check will fail and the packet will be discarded. ESP also doesn't use ports.

For IPsec a 32-bit SPI semi-uniquely identifies an IPsec SA. Since these SAs are unidirectional the ESP/AH header contains only the SPI of the destination's inbound SA (unlike the IKE header which always contains both SPIs). Since the SPIs are locally unique this and the destination address is usually enough to uniquely identify an SA.

Update 21 Oct 2017. I found some useful info in RFC 5114 under Section 4 "Security Considerations". Based on this recommendation, we can consider DH Groups 14 and 24 as too weak to protect AES 128 Symmetric Keys - this leaves DH Groups 19 through 21 ECP as the minimum acceptable Diffie Hellman groups for generating AES symmetric keys (128 bit …

2020年8月13日 · IKE, ESP, and AH Security Associations use secret keys that should be used only for a limited amount of time and to protect a limited amount of data. This limits the lifetime of the entire Security Association. If we used the same keys forever, any compromise of the keys would compromise all the data ever encrypted in this tunnel.

2024年4月5日 · The combination of AH and ESP isn't used much nowadays as IKEv2 doesn't provide the means to negotiate such "SA bundles" (RFC 4301 removed the requirement for such bundles). Share Improve this answer

When ESP and AH are used together (ESP transport, AH transport) on the same packet does ESP encrypt the AH's hash, or is the hash left in the clear? If the hash isn't encrypted, there are obviously security implications (like the AH not ensuring integrity of the authenticated information)

2020年7月4日 · I understand GCM Crypto uses ESP Encryption only for ESP and Authentication algorithm. whereas AES 256 SHA256 uses AES for ESP Encrypt and SHA256 for Auth algorithm. Could someone help clarify the reason of getting a better performance with AES256GCM as compared to ASE256SHA256.