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Understanding Common Criteria and FIPS Terminology and Supported Cryptographic Algorithms

Use the definitions of Common Criteria and FIPS terms, and supported algorithms to help you understand Junos OS.


Common Criteria

Common Criteria for information technology is an international agreement signed by several countries that permits the evaluation of security products against a common set of standards.

Security Administrator

For Common Criteria, user accounts in the TOE have the following attributes: user identity (user name), authentication data (password), and role (privilege). The Security Administrator is associated with the defined login class “security-admin”, which has the necessary permission set to permit the administrator to perform all tasks necessary to manage the Junos OS.


Collaborative Protection Profile for Network Devices, Version 2.2e, dated 23 March 2020.

Critical security parameter (CSP)

Security-related information—for example, secret and private cryptographic keys and authentication data such as passwords and personal identification numbers (PINs)—whose disclosure or modification can compromise the security of a cryptographic module or the information it protects. For details, see Understanding the Operational Environment for Junos OS in FIPS Mode.

Cryptographic module

The set of hardware, software, and firmware that implements approved security functions (including cryptographic algorithms and key generation) and is contained within the cryptographic boundary. For fixed-configuration devices, the cryptographic module is the device case. For modular devices, the cryptographic module is the Routing Engine.


Encapsulating Security Payload (ESP) protocol. The part of the IPsec protocol that guarantees the confidentiality of packets through encryption. The protocol ensures that if an ESP packet is successfully decrypted, and no other party knows the secret key the peers share, the packet was not wiretapped in transit.


Federal Information Processing Standards. FIPS 140-3 specifies requirements for security and cryptographic modules. Junos OS in FIPS mode complies with FIPS 140-3 Level 1.

FIPS maintenance role

The role the Security Administrator assumes to perform physical maintenance or logical maintenance services such as hardware or software diagnostics. For FIPS 140-3 compliance, the Security Administrator zeroizes the Routing Engine on entry to and exit from the FIPS maintenance role to erase all plain-text secret and private keys and unprotected CSPs.


The FIPS maintenance role is not supported on Junos OS in FIPS mode.


A message authentication method that applies a cryptographic technique iteratively to a message of arbitrary length and produces a hash message digest or signature of fixed length that is appended to the message when sent.


Known answer tests. System self-tests that validate the output of cryptographic algorithms approved for FIPS and test the integrity of some Junos OS modules. For details, see Understanding FIPS Self-Tests.


Security association (SA). A connection between hosts that allows them to communicate securely by defining, for example, how they exchange private keys. As Security Administrator, you must manually configure an internal SA on devices running Junos OS in FIPS mode. All values, including the keys, must be statically specified in the configuration. On the devices with more than one Routing Engine, the configuration must match on both ends of the connection between the Routing Engines. For communication to take place, each Routing Engine must have the same configured options, which need no negotiation and do not expire. .


A protocol that uses strong authentication and encryption for remote access across a nonsecure network. SSH provides remote login, remote program execution, file copy, and other functions. It is intended as a secure replacement for rlogin, rsh, and rcp in a UNIX environment. To secure the information sent over administrative connections, use SSHv2 for CLI configuration. In Junos OS, SSHv2 is enabled by default, and SSHv1, which is not considered secure, is disabled.


Erasure of all CSPs and other user-created data on a device before its operation as a FIPS cryptographic module—or in preparation for repurposing the device for non-FIPS operation. The Security Administrator can zeroize the system with a CLI operational command. For details, see Understanding Zeroization to Clear System Data for FIPS Mode.

Supported Cryptographic Algorithms

Table 1 summarizes the high level protocol algorithm support.

Table 1: Protocols Allowed in FIPS Mode


Key Exchange





  • dh-group14-sha1

  • ECDH-sha2-nistp256

  • ECDH-sha2-nistp384

  • ECDH-sha2-nistp521

Host (module):

  • ECDSA P-256


Client (user):

  • ECDSA P-256

  • ECDSA P-384

  • ECDSA P-521


  • RSA-SHA2-256
  • RSA-SHA2-512
  • AES CTR 128

  • AES CTR 256

  • AES CBC 128

  • AES CBC 256

  • HMAC-SHA-1

  • HMAC-SHA-256

  • HMAC-SHA-512

The following cryptographic algorithms are supported in FIPS mode. Symmetric methods use the same key for encryption and decryption, while asymmetric methods use different keys for encryption and decryption.


The Advanced Encryption Standard (AES), defined in FIPS PUB 197. The AES algorithm uses keys of 128 or 256 bits to encrypt and decrypt data in blocks of 128 bits.


A method of key exchange across a nonsecure environment (such as the Internet). The Diffie-Hellman algorithm negotiates a session key without sending the key itself across the network by allowing each party to pick a partial key independently and send part of that key to the other. Each side then calculates a common key value. This is a symmetrical method—keys are typically used only for a short time, discarded, and regenerated.


Elliptic Curve Diffie-Hellman. A variant of the Diffie-Hellman key exchange algorithm that uses cryptography based on the algebraic structure of elliptic curves over finite fields. ECDH allows two parties, each having an elliptic curve public-private key pair, to establish a shared secret over an insecure channel. The shared secret can be used either as a key or to derive another key for encrypting subsequent communications using a symmetric key cipher.


Elliptic Curve Digital Signature Algorithm. A variant of the Digital Signature Algorithm (DSA) that uses cryptography based on the algebraic structure of elliptic curves over finite fields. The bit size of the elliptic curve determines the difficulty of decrypting the key. The public key believed to be needed for ECDSA is about twice the size of the security strength, in bits. ECDSA uses the P-256, P-384, and P-521 curves that can be configured under OpenSSH.


Defined as “Keyed-Hashing for Message Authentication” in RFC 2104, HMAC combines hashing algorithms with cryptographic keys for message authentication.

SHA-256, SHA-384, and SHA-512

Secure hash algorithms (SHA) belonging to the SHA-2 standard defined in FIPS PUB 180-2. Developed by NIST, SHA-256 produces a 256-bit hash digest, SHA-384 produces a 384-bit hash digest, and SHA-512 produces a 512-bit hash digest.


AES-CMAC provides stronger assurance of data integrity than a checksum or an error-detecting code. The verification of a checksum or an error-detecting code detects only accidental modifications of the data, while CMAC is designed to detect intentional, unauthorized modifications of the data, as well as accidental modifications.