A non-FIPS NetScaler appliance stores the server’s private key on the hard disk. On a FIPS appliance, the key is stored in a cryptographic module known as a hardware security module (HSM). Storing a key in the HSM protects it from physical and software attacks. In addition, the keys are encrypted with special FIPS approved ciphers.
Only the NetScaler MPX 9700/10500/12500/15500 FIPS appliances support a FIPS card. Support for FIPS is not available on other MPX appliances, or on the SDX and VPX appliances. This limitation is addressed by supporting a SafeNet network HSM on all NetScaler MPX, SDX, and VPX appliances except the MPX 9700/10500/12500/15500 FIPS appliances.
A SafeNet network HSM is designed to protect critical cryptographic keys and to accelerate sensitive cryptographic operations across a wide range of security applications.