Network User's Guide

Security Features
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NOTE
• ESP is a protocol for carrying out encrypted communication using IPsec. ESP encrypts the payload
(communicated contents) and adds additional information. The IP packet consists of the header and the
encrypted payload, which follows the header. In addition to the encrypted data, the IP packet also includes
information regarding the encryption method and encryption key, the authentication data, and so on.
• AH (Authentication Header) is part of the IPsec protocol that authenticates the sender and prevents
manipulation of the data (ensures the completeness of the data). In the IP packet, the data is inserted
immediately after the header. In addition, the packets include hash values, which are calculated using an
equation from the communicated contents, secret key, and so on, to prevent the falsification of the sender
and manipulation of the data. Unlike ESP, the communicated contents are not encrypted, and the data is
sent and received as plain text.
 Encryption
Select DES, 3DES, AES-CBC 128, or AES-CBC 256. The encryption can be selected only when ESP is
selected in Protocol.
 Hash
Select None, MD5, SHA1, SHA256, SHA384, or SHA512.
None can be selected only when ESP is selected in Protocol.
When AH+ESP is selected in Protocol, select each protocol for Hash(AH) and Hash(ESP).
 SA Lifetime
Specify the IPsec SA lifetime.
Type the time (seconds) and number of kilobytes (KByte).
 Encapsulation Mode
Select Transport or Tunnel.
 Remote Router IP-Address
Specify the IP address (IPv4 or IPv6) of the remote router. Enter this information only when the Tunnel
mode is selected.
NOTE
SA (Security Association) is an encrypted communication method using IPsec or IPv6 that exchanges and
shares information, such as the encryption method and encryption key, to establish a secure
communication channel before communication begins. SA may also refer to an already established virtual
encrypted communication channel. The SA used for IPsec establishes the encryption method, exchanges
the keys, and carries out mutual authentication according to the IKE (Internet Key Exchange) standard
procedure. In addition, the SA is updated periodically.
Perfect Forward Secrecy (PFS)
PFS does not derive keys from the previous keys that were used to encrypt messages. In addition, if a key
that is used to encrypt a message was derived from a parent key, that parent key is not used to derive other
keys. Therefore, even if a key is compromised, the damage is limited only to the messages that were
encrypted using that key.
Select Enabled or Disabled.