Brother SP-1 Online User's Manual page 124

Option
Encapsulating Security
Perfect Forward Secrecy (PFS)
Authentication Method
Description
• Protocol
Select ESP, AH, or AH+ESP.
- ESP is a protocol for carrying out encrypted communication using
IPsec. ESP encrypts the payload (communicated contents) and
adds additional information. The IP packet comprises 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 is part of the IPsec protocol that authenticates the sender and
prevents manipulation (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, in order 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.
• Hash
Select None, MD5, SHA1, SHA256, SHA384 or SHA512.
• SA Lifetime
Specify the IKE SA lifetime.
Type the time (seconds) and number of kilobytes (KByte).
• Encapsulation Mode
Select Transport or Tunnel.
• Remote Router IP-Address
Type the IP address (IPv4 or IPv6) of the remote router. Enter this
information only when the Tunnel mode is selected.
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, in order to establish a
secure communication channel before communication begins. SA
may also refer to a virtual encrypted communication channel that has
been established. 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.
PFS does not derive keys from 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 will be limited only to the
messages that were encrypted using that key.
Select Enabled or Disabled.
Select the authentication method. Select Pre-Shared Key or Certificates.
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