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Understanding the Operational Environment for Junos OS in FIPS Mode


A Juniper Networks EX Series Ethernet Switch running the Juniper Networks Junos operating system (Junos OS) in FIPS mode forms a special type of hardware and software operational environment that is different from the environment of a switch in non-FIPS mode:

Hardware Environment for Junos OS in FIPS Mode

Junos OS in FIPS mode establishes a cryptographic boundary in the switch that no critical security parameters (CSPs) can cross using plain text. Each hardware component of the switch that requires a cryptographic boundary for FIPS 140-2 compliance is a separate cryptographic module.

For more information about the cryptographic boundary on your switch, see Understanding Junos OS in FIPS Mode.

An EX Series switch with redundant Routing Engines contains two separate cryptographic modules. Communications involving CSPs between these secure environments must take place using encryption.

Best Practice

We recommend that you, as Crypto Officer, apply tamper-evident seals to the USB port on all switches to adequately secure the cryptographic module. For details, see Applying Tamper-Evident Seals to Switch Management Ports for FIPS Mode.

If a seal is tampered with, the cryptographic module is considered to be compromised. To restore the module, we recommend that you apply new tamper-evident seals, zeroize the system, and set up new passwords and CSPs.

Cryptographic methods are not a substitute for physical security. The hardware must be located in a secure physical environment. Users of all types must not reveal keys or passwords, or allow written records or notes to be seen by unauthorized personnel.

Software Environment for Junos OS in FIPS Mode

An EX Series switch running Junos OS in FIPS mode forms a special type of nonmodifiable operational environment. To achieve this environment on the switch, the system prevents the execution of any binary file that was not part of the certified Junos OS distribution. When a switch is in FIPS mode, it can run only Junos OS.

FIPS mode on EX Series switches is available starting with Junos OS Release 15.1X53-D55. The Junos OS in FIPS mode software environment is established after the Crypto Officer successfully enables FIPS mode on an EX Series switch. The Junos OS Release 15.1X53-D55 image that includes FIPS mode is available on the Juniper Networks website and can be installed on an EX Series switch.

For FIPS 140-2 compliance, we recommend deleting all user-created files and data from (zeroizing) the system immediately after enabling FIPS mode.


Do not attach the switch to a network until you, the Crypto Officer, complete the configuration from the local console connection.

Critical Security Parameters

Critical security parameters (CSPs) are security-related information such as cryptographic keys and passwords that can compromise the security of the cryptographic module or the security of the information protected by the module if they are disclosed or modified.

Zeroization of the system erases all traces of CSPs in preparation for operating the switch or Routing Engine as a cryptographic module.

Table 1 lists CSPs on switches running Junos OS.

Table 1: Critical Security Parameters





SSH-2 private host key

ECDSA key used to identify the host, generated the first time SSH is configured.

Zeroize command.

Used to identify the host.

SSH-2 session key

Session key used with SSH-2. and as a Diffie-Hellman private key.

Encryption: 3DES, AES-128, AES-192, AES-256.


Key exchange: DH Group exchange (2048 ≤ key ≤ 8192), ECDH Prime curve NID_secp521r1 (NIST Curve P-521).

Power cycle and terminate session.

Symmetric key used to encrypt data between host and client.

User authentication key

Hash of the user’s password: SHA-1, SHA-256, SHA-512.

Zeroize command.

Used to authenticate a user to the cryptographic module.

Crypto Officer authentication key

Hash of the Crypto Officer’s password: SHA-1, SHA-256, SHA-512.

Zeroize command.

Used to authenticate the Crypto Officer to the cryptographic module.

RE-to-RE authentication key

HMAC key (manual IPsec SA): HMAC-SHA1-96 (20 bit), HMAC-SHA-256 (32-bit).

Zeroize/explicitly delete command.

Used to authenticate the RE-to-RE IPSec connection.

RE-to-RE encryption key

TDES key (manual IPsec SA).

Zeroize/explicitly delete command.

Used in IPSec connection between REs.


Seed for deterministic randon bit generator (DRBG).

Seed is not stored by the cryptographic module.

Used for seeding DRBG.


The value (V) of output block length (outlen) in bits, which is updated each time another outlen bits of output are produced.

Power cycle.

A critical value of the internal state of DRBG.

HMAC DRBG key value

The current value of the outlen-bit key, which is updated at least once each time that the DRBG mechanism generates pseudorandom bits.

Power cycle.

A critical value of the internal state of DRBG.

NDRNG entropy

Used as entropy input string to the HMAC DRBG.

Power cycle.

A critical value of the internal state of DRBG.

In Junos OS in FIPS mode, all CSPs must enter and leave the cryptographic module in encrypted form. Any CSP encrypted with a non-approved algorithm is considered plain text by FIPS. However, as the Crypto Officer, you can enter user authentication data in plain text. During initial configuration, you can also enter the IP Security (IPsec) keys for communication between internal Routing Engines or for logical communications between the Routing Engine and system processes in plain text on the console port (under manual key entry rules).

Best Practice

For FIPS compliance, configure the switch over SSH connections because they are encrypted connections.

Local passwords are encrypted with the secure hash algorithm SHA-1, SHA-256, or SHA-512. Password recovery is not possible in Junos OS in FIPS mode. Junos OS in FIPS mode cannot boot into single-user mode without the correct root password.