TLS_DH_anon_WITH_ARIA_128_GCM_SHA256

What each component means

A cipher suite names the algorithms a client and server agree on in one handshake. TLS_DH_anon_WITH_ARIA_128_GCM_SHA256 combines DH key exchange, anon authentication, ARIA-128-GCM encryption and AEAD integrity protection. Each part is explained below with its known weaknesses; for the bigger picture see how cipher suites work.

Key exchange: anonymous DH (anon). The server sends its Diffie-Hellman parameters with no certificate and no signature, so the client cannot tell whether it is talking to the real server. An active man-in-the-middle can run a separate anonymous handshake with each side and read or alter everything; encryption without authentication only stops passive eavesdroppers. Java's default jdk.tls.disabledAlgorithms blocks every anon suite for this reason.

Encryption: ARIA with a 128-bit key, a 128-bit block cipher developed in South Korea and standardised there as KS X 1213 in 2004. Its TLS suites come from the Informational RFC 6209 (2011), and support outside Korean government and financial systems is rare.

Mode: GCM (Galois/Counter Mode), an AEAD: counter-mode encryption plus a GHASH authenticator with a 16-byte tag, checked in one step, so the CBC padding attacks don't apply. In TLS 1.2 the 12-byte nonce is a 4-byte implicit salt from the key block plus an 8-byte explicit part sent with every record, as first specified for AES-GCM in RFC 5288 (2008); a nonce must never repeat under the same key.

Integrity: there is no separate MAC because the AEAD tag authenticates every record. The SHA256 at the end of the name selects the TLS 1.2 PRF hash used to derive keys and compute the Finished messages.

Why this rating

ssl.sh rating: Insecure. The reasons:

• Anonymous key exchange without server authentication, so a man-in-the-middle can impersonate the server.

How ssl.sh rates cipher suites

Which TLS libraries support it

Support for TLS_DH_anon_WITH_ARIA_128_GCM_SHA256 as read from each library's own source code or official documentation on 2026-11-10. “Enabled by default” means the library negotiates it with no configuration; “off by default” means it is implemented but has to be switched on.

None of the 9 libraries tracked here enables it by default. Also implemented by: OpenSSL 3.5.

NSS shows the library's own defaults; Firefox switches every NSS suite off at start-up and re-enables only those with a security.ssl3.* or security.tls13.* preference. Java defaults are derived from the jdk.tls.disabledAlgorithms value Oracle documents for JDK 21, which later updates may extend. The OpenSSL and GnuTLS rows only show whether the suite is implemented.

History and standards status

TLS_DH_anon_WITH_ARIA_128_GCM_SHA256 (0xC0,0x5A) is registered in the IANA TLS Cipher Suites registry with RFC 6209, “Addition of the ARIA Cipher Suites to Transport Layer Security (TLS)” (April 2011, Informational) as its specification. RFC 9325 (2022), part of BCP 195, says implementations SHOULD NOT negotiate static DH or ECDH key agreement because neither has forward secrecy. RFC 10015 (2026) now says clients MUST NOT offer and servers MUST NOT select non-ephemeral FFDH suites in (D)TLS 1.2, and IANA changed this entry's Recommended value to D.

Enable or disable it in Nginx and Apache

This suite is rated insecure, so we don't show how to enable it. Make sure it's excluded.

Disable

Either leave the suite out of your list or exclude it explicitly with a leading "!". Reload the server afterwards (nginx -s reload, apachectl graceful).

# Nginx
ssl_ciphers 'ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:!ADH-ARIA128-GCM-SHA256';

# Apache httpd (mod_ssl)
SSLCipherSuite ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:!ADH-ARIA128-GCM-SHA256

How to test whether a server accepts it

Offer only TLS_DH_anon_WITH_ARIA_128_GCM_SHA256 with openssl s_client; if the handshake completes, the server accepts it:

openssl s_client -connect example.com:443 -tls1_2 -cipher ADH-ARIA128-GCM-SHA256 </dev/null

If the handshake succeeds, the server accepts the suite; "no cipher match" or a handshake failure means it doesn't.

nmap's ssl-enum-ciphers script connects repeatedly, trying one suite at a time, and lists every suite the server accepts with a grade from A to F. Look for TLS_DH_anon_WITH_ARIA_128_GCM_SHA256 in its output:

nmap --script ssl-enum-ciphers -p 443 example.com

To decode a name or hex code, use the cipher suite lookup; the SSL checker shows which protocol versions a live server accepts and the cipher suite it negotiates.