Technical data

Table Of Contents
95
Encryption
Note: Encryption is a software option. The following section applies only for routers with this
option.
For routers shipped with the following encryption options, two variants of encrypted data links over PPP have
been implemented:
PPP DES (RFC1969)
Diffie-Hellman
Encryption requires PPP.
Caution:
DES and Diffie-Hellman encryption options are not available for export outside of the United States
or Canada.
PPP DES (RFC 1969) Encryption
PPP DES (Data Encryption Standard) implementation uses a 56-bit key with fixed transmit and received keys that
are specified in each router. With RFC 1969, users must manage the keys. This implementation has been tested for
interoperability with other PPP DES vendors such as IBM, Network Express (part of Cabletron), and a few others.
Configuration Notes
Simply add the encryption commands to your standard configuration. For PPP DES, the encryption
commands are:
remote setEncryption dese rx <
key
> <
remoteName
>
remote setEncryption dese tx <
key
> <
remoteName
>
Observe the following guidelines:
PPP DES can only be configured using the Command Line Interface (CLI).
The choice of keys should be carefully considered: they must have eight hexadecimal digits and values
that are considered cryptographically weak should be avoided. Consult a security expert for advice.
Use the console port or a telnet port (use the system log command) to view error messages and progress.
If you see 'Unknown protocol' errors, the router receive key and sender Tx key don't match.
Different keys may be used with different remote destinations.
For maximum security, as shown in the following configuration examples, Telnet and SNMP access
should be disabled and PPP CHAP authentication should be used by both ends.