Release Summary:

Add a new security policy for CRT that supports FIPS and TLS1.2

Description of changes:

CRT requested a new security policy based off of AWS-CRT-SDK-TLSv1.2-2023, that supports TLS1.2 and FIPS and does not include CBC cipher suites.

The new policy:

1. Add the "FIPS" rule
2. Add the "forward secrecy" rule
3. Removes the cipher suites:
   • TLS_CHACHA20_POLY1305_SHA256
   • TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
   • TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
   • TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
   • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
   • TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
   • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
   • TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
   • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
   • TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
   • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
   • TLS_RSA_WITH_AES_128_GCM_SHA256
   • TLS_RSA_WITH_AES_256_GCM_SHA384
   • TLS_RSA_WITH_AES_128_CBC_SHA256
   • TLS_RSA_WITH_AES_256_CBC_SHA256
   • TLS_RSA_WITH_AES_128_CBC_SHA
   • TLS_RSA_WITH_AES_256_CBC_SHA
4. Removes the signature schemes:
   • legacy_rsa_pkcs1_sha224
   • legacy_ecdsa_sha224
   • rsa_pkcs1_sha1
   • ecdsa_sha1
5. Prefers EC certs over RSA certs, if multiple certs are configured
6. Removes the named group:
   • x25519

The full diff between AWS-CRT-SDK-TLSv1.2-2023 and the new policy (AWS-CRT-SDK-TLSv1.2-2025):

diff AWS-CRT-SDK-TLSv1.2-2023 AWS-CRT-SDK-TLSv1.2-2025 

1c1
< name: AWS-CRT-SDK-TLSv1.2-2023
---
> name: AWS-CRT-SDK-TLSv1.2-2025
4,5c4,5
< - Perfect Forward Secrecy: no
< - FIPS 140-3 (2019): no
---
> - Perfect Forward Secrecy: yes
> - FIPS 140-3 (2019): yes
9d8
< - TLS_CHACHA20_POLY1305_SHA256
14,29d12
< - TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
< - TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
< - TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
< - TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
< - TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
< - TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
< - TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
< - TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
< - TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
< - TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
< - TLS_RSA_WITH_AES_128_GCM_SHA256
< - TLS_RSA_WITH_AES_256_GCM_SHA384
< - TLS_RSA_WITH_AES_128_CBC_SHA256
< - TLS_RSA_WITH_AES_256_CBC_SHA256
< - TLS_RSA_WITH_AES_128_CBC_SHA
< - TLS_RSA_WITH_AES_256_CBC_SHA
30a14,16
> - ecdsa_sha256
> - ecdsa_sha384
> - ecdsa_sha512
40,46d25
< - legacy_rsa_pkcs1_sha224
< - ecdsa_sha256
< - ecdsa_sha384
< - ecdsa_sha512
< - legacy_ecdsa_sha224
< - rsa_pkcs1_sha1
< - ecdsa_sha1
49d27
< - x25519

Testing:

The new security policy is described above. It also now includes the "fips" and "forward secret" policy rules, which are enforced by unit tests and s2n_init.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.