# TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 cipher suite

> TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 (0xCC,0xAE): RSA/PSK · ChaCha20-Poly1305 · TLS 1.2. ssl.sh rating: Weak. OpenSSL/GnuTLS names and Nginx/Apache config.

Source: https://ssl.sh/ciphers/tls-rsa-psk-with-chacha20-poly1305-sha256/
Last updated: 2026-11-10

TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 (0xCC,0xAE) is a cipher suite for TLS 1.2: RSA key exchange, PSK authentication, ChaCha20-Poly1305 encryption and AEAD message authentication. ssl.sh rates it Weak.

| Field | Value |
|---|---|
| IANA | TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 |
| Hex code | 0xCC,0xAE |
| OpenSSL | RSA-PSK-CHACHA20-POLY1305 |
| GnuTLS | TLS_RSA_PSK_CHACHA20_POLY1305 |
| Key exchange | RSA |
| Authentication | PSK |
| Encryption | ChaCha20-Poly1305 |
| MAC | AEAD |
| TLS versions | TLS 1.2 |
| Rating | Weak |
| IANA "Recommended" | D |
| References | RFC 7905, RFC 10015 |

## 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_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 combines RSA key exchange, PSK authentication, ChaCha20-Poly1305 encryption and AEAD integrity protection. Each part is explained below with its known weaknesses; for the bigger picture see [how cipher suites work](https://ssl.sh/learn/cipher-suites/).

Key exchange: RSA_PSK ([RFC 4279](https://www.rfc-editor.org/rfc/rfc4279)). The server authenticates with an [RSA](https://ssl.sh/glossary/rsa/) certificate and the client with a [pre-shared key](https://ssl.sh/glossary/psk/); the client encrypts part of the premaster secret with the server's RSA public key. Like plain RSA key exchange it has no [forward secrecy](https://ssl.sh/glossary/forward-secrecy/).

Encryption: [ChaCha20-Poly1305](https://ssl.sh/glossary/chacha20-poly1305/), an [AEAD](https://ssl.sh/glossary/aead/) pairing the ChaCha20 stream cipher (256-bit key) with the Poly1305 authenticator and a 16-byte tag. It is fast and constant-time in plain software, so it is the usual choice for devices without AES instructions. [RFC 7905](https://www.rfc-editor.org/rfc/rfc7905) (2016) brought it to TLS 1.2 and builds the 96-bit nonce by XORing the padded record sequence number with the sender's write IV, so no explicit nonce is sent with each record.

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

- 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.

## Which TLS libraries support it

Support for TLS_RSA_PSK_WITH_CHACHA20_POLY1305_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 `RSA-PSK-CHACHA20-POLY1305` |
| GnuTLS | Implemented | name `TLS_RSA_PSK_CHACHA20_POLY1305`; minimum protocol `TLS 1.2` |
| BoringSSL | Not supported | - |
| Go crypto/tls | Not supported | - |
| NSS 3.133 | Not supported | - |
| Firefox | Not supported | - |
| Java 21 (SunJSSE) | Not supported | - |
| Windows Schannel (Windows 11 / Server 2022) | Not supported | - |
| rustls 0.23.46 | Not supported | - |

None of the 9 libraries tracked here enables it by default. 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_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 (0xCC,0xAE) is registered in the IANA TLS Cipher Suites registry with [RFC 7905](https://www.rfc-editor.org/rfc/rfc7905), “ChaCha20-Poly1305 Cipher Suites for Transport Layer Security (TLS)” (June 2016, Standards Track) as its specification. [RFC 10015](https://www.rfc-editor.org/rfc/rfc10015) (2026) now says clients MUST NOT offer and servers MUST NOT select RSA key-exchange suites in (D)TLS 1.2, and IANA changed this entry's Recommended value to D.

## Nginx / Apache

Disable

```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:!RSA-PSK-CHACHA20-POLY1305';
```

```apache
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:!RSA-PSK-CHACHA20-POLY1305
```


## How to test whether a server accepts it

Offer only TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 with openssl s_client; if the handshake completes, the server accepts it:

```bash
openssl s_client -connect example.com:443 -tls1_2 -cipher RSA-PSK-CHACHA20-POLY1305 </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_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 in its output:

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

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_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 secure?

Only with caveats: ssl.sh rates it weak. 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. [RFC 10015](https://www.rfc-editor.org/rfc/rfc10015) (2026) now says clients MUST NOT offer and servers MUST NOT select RSA key-exchange suites in (D)TLS 1.2, and IANA changed this entry's Recommended value to D.

### Can TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 be used with TLS 1.3?

No. TLS 1.3 has its own suites that name only the AEAD and the hash, and TLS 1.2 suites can't be used in a TLS 1.3 handshake. TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 works with TLS 1.2. The closest TLS 1.3 suite is [TLS_CHACHA20_POLY1305_SHA256](https://ssl.sh/ciphers/tls-chacha20-poly1305-sha256/), which TLS 1.3 combines with a separately negotiated key exchange such as X25519.

### How do I disable TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 in Nginx or Apache?

Exclude it by its OpenSSL name: append `!RSA-PSK-CHACHA20-POLY1305` to `ssl_ciphers` in Nginx or to `SSLCipherSuite` in Apache httpd. Listing only the suites you want, as in the snippet above, works even better. Reload the server and repeat the openssl s_client test to confirm the handshake now fails.

### Which clients and libraries still support TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256?

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