| ||ipsecesp, ESP - IPsec Encapsulating Security Payload
The ipsecesp module provides confidentiality, integrity,
authentication, and partial sequence integrity (replay protection) to IP datagrams. The encapsulating security payload (ESP)
encapsulates its data, enabling it to protect data that follows in the datagram.
For TCP packets, ESP encapsulates the TCP header and its data only. If the packet is an IP
in IP datagram, ESP protects the inner IP datagram. Per-socket policy allows "self-encapsulation" so ESP can encapsulate IP options when necessary.
Unlike the authentication header (AH), ESP allows multiple varieties of datagram protection. (Using a single
datagram protection form can expose vulnerabilities.) For example, only ESP can be used to provide confidentiality. But protecting confidentiality
alone exposes vulnerabilities in both replay attacks and cut-and-paste attacks.
Similarly, if ESP protects only integrity and does not
fully protect against eavesdropping, it may provide weaker protection than AH. See ipsecah(7P).
Algorithms and the ESP Device
ESP is implemented as a module that is auto-pushed
on top of IP. Use the /dev/ipsecesp
entry to tune ESP with ndd(1M),
as well as to allow future algorithms to be loaded on top of ESP. ESP allows encryption algorithms to be pushed
on top of it, in addition to the authentication algorithms that can be used
in AH. Authentication algorithms include HMAC-MD5 and HMAC-SHA-1. See authmd5h(7M) and authsha1(7M). Encryption algorithms include DES, Triple-DES, Blowfish and AES. See encrdes(7M), encr3des(7M), encrbfsh(7M) and encraes(7M). Each
authentication and encryption algorithm contain key size and key format properties.
Because of export laws in the United States, not all encryption algorithms
are available outside of the United States.
ESP without authentication exposes vulnerabilities
to cut-and-paste cryptographic attacks as well as eavesdropping attacks. Like
AH, ESP is vulnerable to eavesdropping when used without
for descriptions of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE
| ||SUNWcarx (64-bit)
ipsecconf(1M), ndd(1M), attributes(5), authmd5h(5), authsha1(7M), encrdes(7M), encr3des(7M), encrbfsh(7M), ip(7P), ipsec(7P), ipsecah(7P)
Kent, S. and Atkinson, R.RFC 2406, IP Encapsulating Security
Payload (ESP), The Internet Society, 1998.