TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256

What each component means

A cipher suite names the algorithms a client and server agree on in one handshake. TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256 combines ECDH key exchange, RSA authentication, AES-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: static ECDH. The server's elliptic-curve DH key is fixed in its certificate, so there is no forward secrecy, and a server that reuses one ECDH key without validating the client's point is open to invalid-curve attacks (Jager, Schwenk and Somorovsky, 2015). The RSA in the name is the algorithm the CA used to sign the ECDH certificate, not a signature made during the handshake.

Encryption: AES with a 128-bit key, the 128-bit block cipher of FIPS 197 (2001). Most server and phone CPUs have AES instructions (AES-NI on x86, the ARMv8 cryptography extensions), which make it fast and avoid the cache-timing leaks of table-based software implementations.

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: Weak. The reasons:

• No forward secrecy: the session keys are protected by the server's long-term key (static RSA/DH/ECDH, PSK or Kerberos), so a leaked key decrypts recorded traffic.

How ssl.sh rates cipher suites

Which TLS libraries support it

Support for TLS_ECDH_RSA_WITH_AES_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. Supported but off by default in: Java 21 (SunJSSE). 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_ECDH_RSA_WITH_AES_128_GCM_SHA256 (0xC0,0x31) is registered in the IANA TLS Cipher Suites registry with RFC 5289, “TLS Elliptic Curve Cipher Suites with SHA-256/384 and AES Galois Counter Mode (GCM)” (August 2008, Standards Track) 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) also says clients SHOULD NOT offer and servers SHOULD NOT select non-ephemeral ECDH suites in (D)TLS 1.2, and IANA changed this entry's Recommended value to D.

Enable or disable it in Nginx and Apache

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:!ECDH-RSA-AES128-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:!ECDH-RSA-AES128-GCM-SHA256

How to test whether a server accepts it

Offer only TLS_ECDH_RSA_WITH_AES_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 ECDH-RSA-AES128-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_ECDH_RSA_WITH_AES_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.