Tenda W15E User Manual page 107

Parameter
Algorithm
Integrity
Verification
Algorithm
Diffie-Hellman
Group
Key Expiration
PFS
Key Negotiation Method – Manual Negotiation
To access the page, select Manual Negotiation from the drop-down list box of Key Negotiation Method.
Parameter description
Parameter
ESP Encryption
Algorithm
Description
The router supports the following two encryption algorithms:
DES: Data Encryption Standard. It uses a 56-bits key to encrypt 64 bits data with the

last 8 bits reserved for parity checking.3DES, or triple DES, uses three 56-bit keys to
encrypt.
AES: Advanced Encryption Standard. AES128/192/256 indicates that it uses

128/192/256-bit keys to encrypt.
It specifies the verification algorithm applied to IKE conversation.
The router supports the following two verification algorithms:
MD5: The message digest algorithm generates a 128 bit digest to prevent data

tampering.
SHA1: The secure hash algorithm generates a 160 bit digest, which is more difficult to

crack than MD5.
It specifies the group information for Diffie-Hellman algorithm. It is used to generate the
key to encrypt an IKE tunnel.
It specifies the lifetime of IPSec SA.
Keys made with Perfect Froward Secrecy (PFS) in IKE period 2 have nothing to do with
the previous keys generated in period 1. Therefore, keys in period 2 remains secure even
if keys in period 1 have been compromised.
If the PFS is disabled, new session keys are made from the previous keys. Once the
previous keys are compromised, new session keys are insecure too, threatening the
communication security.
Description
The ESP encryption algorithm is configurable when ESP is selected as the Tunnel
Protocol.
The router supports the following two encryption algorithms:
DES: Data Encryption Standard. It uses a 56-bit key to encrypt a 64-bit data with

the last 8 bits reserved for parity checking. While the triple DES uses three 56-bit
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