ZyXEL Communications P-792H - Page 164

Chapter 12 VPN
P-792H v2 User’s Guide
164
Pre-Shared Key Click the button to use a pre-shared key for authentication, and type in
your pre-shared key. A pre-shared key identifies a communicating
party during a phase 1 IKE negotiation. It is called "pre-shared"
because you have to share it with another party before you can
communicate with them over a secure connection.
Type from 8 to 31 case-sensitive ASCII characters or from 16 to 62
hexadecimal ("0-9", "A-F") characters. You must precede a
hexadecimal key with a "0x” (zero x), which is not counted as part of
the 16 to 62 character range for the key. For example, in
"0x0123456789ABCDEF", “0x” denotes that the key is hexadecimal
and “0123456789ABCDEF” is the key itself.
Both ends of the VPN tunnel must use the same pre-shared key. You
will receive a “PYLD_MALFORMED” (payload malformed) packet if the
same pre-shared key is not used on both ends.
Encryption
Algorithm
Select DES, 3DES, AES or NULL from the drop-down list box.
When you use one of these encryption algorithms for data
communications, both the sending device and the receiving device
must use the same secret key, which can be used to encrypt and
decrypt the message or to generate and verify a message
authentication code. The DES encryption algorithm uses a 56-bit key.
Triple DES (3DES) is a variation on DES that uses a 168-bit key. As a
result, 3DES is more secure than DES. It also requires more
processing power, resulting in increased latency and decreased
throughput. This implementation of AES uses a 128-bit key. AES is
faster than 3DES.
Select NULL to set up a tunnel without encryption. When you select
NULL, you do not enter an encryption key.
Authentication
Algorithm
Select SHA1 or MD5 from the drop-down list box. MD5 (Message
Digest 5) and SHA1 (Secure Hash Algorithm) are hash algorithms used
to authenticate packet data. The SHA1 algorithm is generally
considered stronger than MD5, but is slower. Select MD5 for minimal
security and SHA-1 for maximum security.
Back Click Back to return to the previous screen.
Apply Click Apply to save your changes back to the P-792H v2.
Cancel Click Cancel to begin configuring this screen afresh.
Advanced Setup Click Advanced Setup to configure more detailed settings of your IKE
key management.
Table 44 Security > VPN > Setup > Edit
LABEL DESCRIPTION