Black Box ET0010A User Manual

Page of 352
ETEP Configuration
338
EncrypTight User Guide
Selecting the Traffic Handling Mode
The ETEP has three options for processing packets:
Encrypt all packets
Discard all packets
Pass all packets in the clear
Under normal operation, the ETEP is configured to encrypt all traffic that is exchanged between two peer 
appliances. This is the ETEP’s default mode of operation. Other methods of traffic handling are used for 
debugging and troubleshooting. The traffic handling setting persists through a reboot. 
How the ETEP Encrypts and Authenticates Traffic
When operating as a Layer 2 encryptor in a point-to-point policy, the ETEP’s encapsulation mode 
authenticates the encrypted frame’s Ethernet payload. The ETEP uses the AES algorithm with 256-bit 
keys to encrypt the Ethernet payload. The HMAC-SHA-1 authentication algorithm provides the data 
origin authentication and data integrity.
Figure 117 Layer 2 encrypted frame format 
To encrypt traffic, ETEPs must establish security associations (SAs). A security association defines the 
processing to be done on a specific packet. It associates security services and a key with the traffic to be 
protected and the remote peer with whom secured traffic is being exchanged. The SA is a unidirectional 
secure tunnel through which data passes between the two appliances. Each secure connection has two 
SAs, one for each direction. SAs are identified by a value called an SPI. 
In point-to-point Layer 2 configurations the SAs are automatically negotiated using IKE. Timeout values 
force the IKE protocol to renegotiate the IKE Phase 1 and Phase 2 keys periodically. The ETEP can uses 
a preshared key for authentication in IKE negotiations. 
. These values are 
hard-coded and cannot be modified by the user.
Table 107   IKE Phase 1 Parameters
Parameter
Value
Cipher algorithm
AES-256
Hash algorithm
HMAC-SHA-1
Diffie-Hellman group
5
Lifetime
24 hours
Negotiation mode
Main mode
Table 108  IKE Phase 2 Parameters
Parameter
Value
Cipher algorithm
AES-256