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Appendix A. TLS 1.2 Cipher Suite Black List

An HTTP/2 implementation MAY treat the negotiation of cipher suites in this blacklist as a connection error of type INADEQUATE_SECURITY.

The following cipher suites are blacklisted due to known vulnerabilities or weak security properties:

Blacklisted Cipher Suites​

The blacklist includes:

  • NULL encryption cipher suites
  • RC4 cipher suites
  • DES and 3DES cipher suites
  • Export-strength cipher suites
  • Cipher suites with weak key exchange
  • Cipher suites without forward secrecy

Implementation Requirements​

Implementations MUST support:

  • TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 [TLS-ECDHE] with P-256 elliptic curve [FIPS186]

Security Considerations​

Deployments that want to avoid the vulnerabilities described in this appendix SHOULD NOT negotiate cipher suites that use:

  • NULL encryption
  • Stream ciphers (e.g., RC4)
  • Block ciphers without AEAD mode (e.g., CBC mode)
  • Weak key exchange mechanisms

Note: For the complete and authoritative list of blacklisted cipher suites, please refer to the official RFC 7540 specification at:
````https://www.rfc-editor.org/rfc/rfc7540.txt\````

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