# TLS_AES_128_GCM_SHA256 cipher suite

> TLS_AES_128_GCM_SHA256 (0x13,0x01): any (negotiated separately)/any (negotiated separately) · AES-128-GCM · TLS 1.3. ssl.sh rating: Recommended. OpenSSL/GnuTLS names and Nginx/Apache config.

Source: https://ssl.sh/ciphers/tls-aes-128-gcm-sha256/
Last updated: 2026-11-10

TLS_AES_128_GCM_SHA256 (0x13,0x01) is a TLS 1.3 cipher suite: AES-128-GCM authenticated encryption with SHA256 as the HKDF hash. In TLS 1.3 the key exchange and authentication are negotiated separately, so the suite name doesn't contain them. ssl.sh rates it Recommended.

| Field | Value |
|---|---|
| IANA | TLS_AES_128_GCM_SHA256 |
| Hex code | 0x13,0x01 |
| OpenSSL | TLS_AES_128_GCM_SHA256 |
| GnuTLS | TLS_AES_128_GCM_SHA256 |
| Key exchange | any (negotiated separately) |
| Authentication | any (negotiated separately) |
| Encryption | AES-128-GCM |
| MAC | AEAD |
| TLS versions | TLS 1.3 |
| Rating | Recommended |
| IANA "Recommended" | Y |
| References | RFC 9846 |

## What each component means

A [cipher suite](https://ssl.sh/glossary/cipher-suite/) names the algorithms a client and server agree on in one handshake. TLS_AES_128_GCM_SHA256 combines the AES-128-GCM AEAD with the SHA256 hash. Each part is explained below with its known weaknesses; for the bigger picture see [how cipher suites work](https://ssl.sh/learn/cipher-suites/).

TLS 1.3 suites only describe the symmetric part. The TLS 1.3 specification ([RFC 9846](https://www.rfc-editor.org/rfc/rfc9846)) says its suites specify only the symmetric ciphers and cannot be used with TLS 1.2. Key exchange is negotiated separately through the supported_groups and key_share extensions (for example X25519, P-256 or the hybrid X25519MLKEM768) and is always ephemeral (EC)DHE unless a client resumes in the PSK-only psk_ke mode, so a full handshake always has [forward secrecy](https://ssl.sh/glossary/forward-secrecy/). The certificate signature algorithm (for example RSA-PSS, [ECDSA](https://ssl.sh/glossary/ecdsa/) or Ed25519) is negotiated with signature_algorithms. In TLS_AES_128_GCM_SHA256, SHA256 is the hash behind the HKDF key schedule and the handshake transcript hash.

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](https://ssl.sh/glossary/aead/): counter-mode encryption plus a GHASH authenticator with a 16-byte tag, checked in one step. In TLS 1.3 the nonce is the record sequence number XORed with a per-direction IV, so nothing extra travels with each record and nonces cannot repeat.

## Why this rating

- A TLS 1.3 suite marked "Recommended" by IANA; TLS 1.3 always uses ephemeral key exchange and AEAD.

## Which TLS libraries support it

Support for TLS_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.

| Library | Status | Details |
|---|---|---|
| OpenSSL 3.5 | Implemented | cipher string `TLS_AES_128_GCM_SHA256` |
| GnuTLS | Implemented | name `TLS_AES_128_GCM_SHA256`; minimum protocol `TLS 1.3` |
| BoringSSL | Enabled by default | - |
| Go crypto/tls | Enabled by default | returned by tls.CipherSuites() |
| NSS 3.133 | Enabled by default | NSS library default |
| Firefox | Enabled by default | about:config pref `security.tls13.aes_128_gcm_sha256` |
| Java 21 (SunJSSE) | Enabled by default | - |
| Windows Schannel (Windows 11 / Server 2022) | Enabled by default | - |
| rustls 0.23.46 | Enabled by default | - |

Enabled by default in 7 of the 9 libraries tracked here: BoringSSL, Go crypto/tls, NSS 3.133, Firefox, Java 21 (SunJSSE), Windows Schannel (Windows 11 / Server 2022) and rustls 0.23.46. Also implemented by: OpenSSL 3.5 and GnuTLS.

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.

- [BoringSSL — ssl/ssl_cipher.cc (main)](https://boringssl.googlesource.com/boringssl/+/refs/heads/main/ssl/ssl_cipher.cc) (2026-11-10)
- [Go — src/crypto/tls/cipher_suites.go (master)](https://github.com/golang/go/blob/master/src/crypto/tls/cipher_suites.go) (2026-11-10)
- [Go — src/crypto/tls/defaults.go (master)](https://github.com/golang/go/blob/master/src/crypto/tls/defaults.go) (2026-11-10)
- [NSS — lib/ssl/ssl3con.c (as vendored in Firefox)](https://github.com/mozilla-firefox/firefox/blob/main/security/nss/lib/ssl/ssl3con.c) (2026-11-10)
- [NSS — TAG-INFO](https://github.com/mozilla-firefox/firefox/blob/main/security/nss/TAG-INFO) (2026-11-10)
- [Firefox — security/manager/ssl/nsNSSComponent.cpp](https://github.com/mozilla-firefox/firefox/blob/main/security/manager/ssl/nsNSSComponent.cpp) (2026-11-10)
- [Firefox — modules/libpref/init/StaticPrefList.yaml](https://github.com/mozilla-firefox/firefox/blob/main/modules/libpref/init/StaticPrefList.yaml) (2026-11-10)
- [Oracle — JDK 21 Providers Documentation: SunJSSE Cipher Suites](https://docs.oracle.com/en/java/javase/21/security/oracle-providers.html#GUID-7093246A-31A3-4304-AC5F-5FB6400405E2) (2026-11-10)
- [Oracle — JDK 21 JSSE Reference Guide: jdk.tls.disabledAlgorithms](https://docs.oracle.com/en/java/javase/21/security/java-secure-socket-extension-jsse-reference-guide.html) (2026-11-10)
- [Microsoft Learn — TLS Cipher Suites in Windows 11](https://learn.microsoft.com/en-us/windows/win32/secauthn/tls-cipher-suites-in-windows-11) (2026-11-10)
- [Microsoft Learn — TLS Cipher Suites in Windows Server 2022](https://learn.microsoft.com/en-us/windows/win32/secauthn/tls-cipher-suites-in-windows-server-2022) (2026-11-10)
- [docs.rs — rustls 0.23.46 crypto::aws_lc_rs (default provider)](https://docs.rs/rustls/0.23.46/src/rustls/crypto/aws_lc_rs/mod.rs.html) (2026-11-10)

## History and standards status

TLS_AES_128_GCM_SHA256 (0x13,0x01) is registered in the IANA TLS Cipher Suites registry with [RFC 9846](https://www.rfc-editor.org/rfc/rfc9846), “The Transport Layer Security (TLS) Protocol Version 1.3” (July 2026, Standards Track) as its specification. TLS 1.3 was first published as [RFC 8446](https://www.rfc-editor.org/rfc/rfc8446) (2018) and republished as [RFC 9846](https://www.rfc-editor.org/rfc/rfc9846) (2026), which obsoletes RFC 8446. Section 9.1 of the specification makes TLS_AES_128_GCM_SHA256 mandatory to implement and says implementations SHOULD also support TLS_AES_256_GCM_SHA384 and TLS_CHACHA20_POLY1305_SHA256. The registry marks it Recommended (Y).

## Nginx / Apache

Enable

```nginx
ssl_protocols TLSv1.2 TLSv1.3;
# nginx 1.19.4+ with OpenSSL 1.1.1+
ssl_conf_command Ciphersuites TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256;
```

```apache
SSLProtocol -all +TLSv1.2 +TLSv1.3
SSLCipherSuite TLSv1.3 TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256
```

Disable

```nginx
ssl_conf_command Ciphersuites TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256;
```

```apache
SSLCipherSuite TLSv1.3 TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
```


## How to test whether a server accepts it

Offer only TLS_AES_128_GCM_SHA256 with openssl s_client; if the handshake completes, the server accepts it:

```bash
openssl s_client -connect example.com:443 -tls1_3 -ciphersuites TLS_AES_128_GCM_SHA256 </dev/null
```

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_AES_128_GCM_SHA256 in its output:

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

If your nmap build doesn't print a TLS 1.3 section, rely on the openssl command instead.

To decode a name or hex code, use the [cipher suite lookup](https://ssl.sh/tools/cipher-suite-lookup/); the [SSL checker](https://ssl.sh/tools/ssl-checker/) shows which protocol versions a live server accepts and the cipher suite it negotiates.

## FAQ

### Is TLS_AES_128_GCM_SHA256 secure?

Yes. ssl.sh rates it recommended. A TLS 1.3 suite marked "Recommended" by IANA; TLS 1.3 always uses ephemeral key exchange and AEAD. Section 9.1 of the specification makes TLS_AES_128_GCM_SHA256 mandatory to implement and says implementations SHOULD also support TLS_AES_256_GCM_SHA384 and TLS_CHACHA20_POLY1305_SHA256.

### Can TLS_AES_128_GCM_SHA256 be used with TLS 1.3?

Yes. It is a TLS 1.3 suite, so it only works with TLS 1.3; a TLS 1.2 handshake cannot negotiate it. OpenSSL enables it by default (TLS_AES_128_GCM_SHA256 is in OpenSSL's default TLS 1.3 list).

### How do I enable TLS_AES_128_GCM_SHA256 in Nginx or Apache?

TLS 1.3 suites are not controlled by `ssl_ciphers`. List `TLS_AES_128_GCM_SHA256` in `ssl_conf_command Ciphersuites` in Nginx (1.19.4+ with OpenSSL 1.1.1+) or in `SSLCipherSuite TLSv1.3` in Apache httpd, then reload.

### Which clients and libraries still support TLS_AES_128_GCM_SHA256?

Out of the box: BoringSSL, Go crypto/tls, NSS 3.133, Firefox, Java 21 (SunJSSE), Windows Schannel (Windows 11 / Server 2022) and rustls 0.23.46. Implemented, default state not tracked here: OpenSSL 3.5 and GnuTLS.