Commercial National Security Algorithm Suite

The Commercial National Security Algorithm Suite (CNSA) is a set of cryptographic algorithms promulgated by the National Security Agency as a replacement for NSA Suite B Cryptography algorithms. It serves as the cryptographic base to protect US National Security Systems information up to the TOP SECRET level. Two versions of CNSA exist: the pre-quantum 1.0 of 2015 and the quantum-resistant 2.0 of 2022.[1][2][3][4][5][6]
Contents
[edit]CNSA 1.0
[edit]A singular parameter length is provided for protection up to TOP SECRET level.
Purpose | Algorithm | Standard | Parameter Length | Bits of Security | Notes |
---|---|---|---|---|---|
Symmetric encryption | AES | FIPS 197 | 256 | 256 | |
Digital Signature | Elliptic Curve Digital Signature Algorithm (ECDSA) | FIPS 186-4 | 384 | 192 | Use curve P-384 only. |
RSA | FIPS 186-4 | 3072 | 128 | Minimum modulus size, can be larger. | |
Key agreement | Elliptic-curve Diffie–Hellman (ECDH) | NIST SP 800-56Ar3 | 384 | 192 | Use curve P-384 only. |
Diffie–Hellman key exchange | RFC 3526 | 3072 | 128 | Minimum modulus size, can be larger. | |
RSA | FIPS SP 800-56Br2 | 3072 | 128 | Minimum modulus size, can be larger. | |
Message digest | SHA-2 | FIPS 180-4 | 384 | 192 | Use exactly SHA-384. |
The CNSA 1.0 transition is notable for moving RSA from a temporary legacy status, as it appeared in Suite B, to supported status. It also did not include the Digital Signature Algorithm. This, and the overall delivery and timing of the announcement, in the absence of post-quantum standards, raised considerable speculation about whether NSA had found weaknesses e.g. in elliptic-curve algorithms or others, or was trying to distance itself from an exclusive focus on ECC for non-technical reasons.[7][8][9]
Documents describing the integration of CNSA 1.0 with Internet protocols include:
- RFC 9151 Commercial National Security Algorithm (CNSA) Suite Profile for TLS and DTLS 1.2 and 1.3
- RFC 9206 Commercial National Security Algorithm (CNSA) Suite Cryptography for Internet Protocol
- RFC 9212 Commercial National Security Algorithm (CNSA) Suite Cryptography for Secure Shell (SSH)
- RFC 8755 Using Commercial National Security Algorithm Suite Algorithms in Secure/Multipurpose
- RFC 8756 Commercial National Security Algorithm (CNSA) Suite Profile of Certificate Management over CMS
- RFC 8603 Commercial National Security Algorithm (CNSA) Suite Certificate and Certificate Revocation List (CRL) Profile
CNSA 2.0
[edit]In September 2022, the NSA announced CNSA 2.0, which includes its first recommendations for post-quantum cryptographic algorithms. Again, all parameters are provided for TOP SECRET level.[10]
Purpose | Algorithm | Standard | Parameter Length | Bits of Security | Notes |
---|---|---|---|---|---|
Symmetric encryption | AES | FIPS 197-upd1 | 256 | 256 | |
Key agreement | ML-KEM | FIPS 203 | ML-KEM-1024 | 256 | |
Digital signature | ML-DSA | FIPS 204 | ML-DSA-87 | 256 | |
Message digest of data | SHA-2 | FIPS 180-4 | 384 or 512 | 192 or 256 | |
Digital signature of firmware and software | Leighton-Micali | NIST SP 800-208 | 192 or 256 | 192 or 256 | All standard parameter sets are approved, the minimum being SHA256/192. SHA256/192 is the recommended choice. |
Xtended Merkle | NIST SP 800-208 | 192 or 256 | 192 or 256 | All standard parameter sets are approved, the minimum being SHA256/192. | |
Message digest for hardware integrity checks | |||||
SHA-3 | FIPS 202 | 384 or 512 | 192 or 256 | Allowed for internal hardware functionality only (e.g., boot-up integrity checks) |
Note that compared to CNSA 1.0, CNSA 2.0:
- Suggests separate post-quantum algorithms (XMSS/LMS) for software/firmware signing for use immediately
- Allows SHA-512
- Announced the selection of CRYSTALS-Kyber and CRYSTALS-Dilithium early, with the expectation that they will be mandated only when the final standards and FIPS-validated implementations are released. RSA, Diffie-Hellman, and elliptic curve cryptography will be deprecated at that time.
Documents describing the integration of CNSA 2.0 with Internet protocols include:
- draft-becker-cnsa2-smime-profile-01 Commercial National Security Algorithm (CNSA) Suite Profile for Secure/Multipurpose Internet Mail Extensions (S/MIME)
- draft-becker-cnsa2-ssh-profile-02 Commercial National Security Algorithm (CNSA) Suite Profile for SSH
- draft-becker-cnsa2-tls-profile-02 Commercial National Security Algorithm (CNSA) Suite Profile for TLS 1.3
- draft-guthrie-cnsa2-ipsec-profile-01 Commercial National Security Algorithm (CNSA) Suite 2.0 Profile for IPsec
- draft-jenkins-cnsa2-cmc-profile-01 Commercial National Security Algorithm (CNSA) Suite Profile of Certificate Management over CMS
- draft-jenkins-cnsa2-pkix-profile-03 Commercial National Security Algorithm Suite Certificate and Certificate Revocation List Profile
References
[edit]- ^ Cook, John (2019-05-23). "NSA recommendations | algorithms to use until PQC". www.johndcook.com. Retrieved 2020-02-28.
- ^ "Announcing the Commercial National Security Algorithm Suite 2.0" (PDF). media.defense.gov. 2022-09-07. Archived from the original (PDF) on September 8, 2022. Retrieved 2024-06-10.
- ^ "CNSA Suite and Quantum Computing FAQ" (PDF). cryptome.org. January 2016. Retrieved 24 July 2023.
- ^ "Use of public standards for the secure sharing of information among national security systems, Advisory Memorandum 02-15 CNSS Advisory Memorandum Information Assurance 02-15". Committee on National Security Systems. 2015-07-31. Archived from the original on 2020-02-28. Retrieved 2020-02-28.
- ^ "Commercial National Security Algorithm Suite". apps.nsa.gov. 19 August 2015. Archived from the original on 2022-02-18. Retrieved 2020-02-28.
- ^ Housley, Russ; Zieglar, Lydia (July 2018). "RFC 8423 - Reclassification of Suite B Documents to Historic Status". tools.ietf.org. Retrieved 2020-02-28.
- ^ "NSA's FAQs Demystify the Demise of Suite B, but Fail to Explain One Important Detail – Pomcor". 9 February 2016. Retrieved 2020-02-28.
- ^ "A riddle wrapped in a curve". A Few Thoughts on Cryptographic Engineering. 2015-10-22. Retrieved 2020-02-28.
- ^ Koblitz, Neal; Menezes, Alfred J. (2018-05-19). "A Riddle Wrapped in an Enigma". Cryptology ePrint Archive.
- ^ "Post-Quantum Cybersecurity Resources". www.nsa.gov. Retrieved 2023-03-03.
- ^ "Announcing the Commercial National Security Algorithm Suite 2.0, U/OO/194427-22, PP-22-1338, Ver. 1.0" (PDF). media.defense.gov. National Security Agency. September 2022. Table IV: CNSA 2.0 algorithms, p. 9.; Table V: CNSA 1.0 algorithms, p. 10. Archived from the original (PDF) on September 8, 2022. Retrieved 2024-04-14.