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Understanding FIPS Mode Terminology and Supported Cryptographic Algorithms


Use the definitions of FIPS terms and supported algorithms to help you understand Junos OS in FIPS mode.

FIPS Terminology

Common CriteriaCommon 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 AdministratorFor 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.
NDcPPCollaborative Protection Profile for Network Devices, version 2.1.
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 moduleThe set of hardware, software, and firmware that implements approved security functions (including cryptographic algorithms and key generation) and is contained within the cryptographic boundary. MX Series routers are certified at FIPS 140-2 Level 1. For fixed-configuration routers, the cryptographic module is the router case. For modular routers, the cryptographic module is the Routing Engine.
Crypto OfficerPerson with appropriate permissions who is responsible for securely enabling, configuring, monitoring, and maintaining Junos OS in FIPS mode on a router. For details, see Understanding Roles and Services for Junos OS in FIPS.
FIPSFederal Information Processing Standards. FIPS 140-2 specifies requirements for security and cryptographic modules. Junos OS in FIPS mode complies with FIPS 140-2 Level 1.
FIPS maintenance roleThe role the Crypto Officer assumes to perform physical maintenance or logical maintenance services such as hardware or software diagnostics. For FIPS 140-2 compliance, the Crypto Officer 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.

HashingA 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.
KATsKnown 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.
NDcPPCollaborative Protection Profile for Network Devices, version 2.0, dated 05 May 2017.
SSHA 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.
ZeroizationErasure of all CSPs and other user-created data on a router before its operation as a FIPS cryptographic module—or in preparation for repurposing the routeres for non-FIPS operation. The Crypto Officer can zeroize the system with a CLI operational command.

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

  • AES CTR 128

  • AES CTR 256

  • AES CBC 128

  • AES CBC 256

  • HMAC-SHA-1

  • HMAC-SHA-256

  • HMAC-SHA-512

Table 2: MIC-MACSEC-20G LC Supported Ciphers

MIC-MACSEC-20G LC Supported Ciphers



Each implementation of an algorithm is checked by a series of known answer test (KAT) self-tests. Any self-test failure results in a FIPS error state.

Best Practice

For FIPS 140-2 compliance, use only FIPS-approved cryptographic algorithms in Junos OS in FIPS mode.

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

AESThe 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.
AES-GCMMACsec utilizes the Galois/Counter Mode Advanced Encryption Standard (AES-GCM). The default cipher suite used for MACsec is AES-GCM-128, with a maximum key length of 128 bits. MACsec also supports AES-GCM-256, with a maximum key length of 256 bits.
Diffie-HellmanA 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, and keys are typically used only for a short time, discarded, and regenerated.
ECDHElliptic 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.
ECDSAElliptic 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 level, in bits. ECDSA using the P-256 curve can be configured under OpenSSH.
HMACDefined as “Keyed-Hashing for Message Authentication” in RFC 2104, HMAC combines hashing algorithms with cryptographic keys for message authentication. For Junos OS in FIPS mode, HMAC uses the iterated cryptographic hash function SHA-1 (designated as HMAC-SHA1) along with a secret key.
RSAAlgorithm for public key cryptography that is based on the presumed difficulty of factoring large integers of up to 2048 bits. The RSA algorithm involves three steps: key generation, encryption, and decryption. SSHv2 requires the asymmetric algorithm RSA-2048 with 2,048 bits (617 decimal digits), the largest of the RSA integers. The RSA algorithm is used in the validation of Juniper Networks signed binaries and is also available and used with the ssh command.

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