TLS_ECDHE_PSK_WITH_RC4_128_SHA

What each component means

A cipher suite names the algorithms a client and server agree on in one handshake. TLS_ECDHE_PSK_WITH_RC4_128_SHA combines ECDHE key exchange, PSK authentication, RC4-128 encryption and SHA1 integrity protection. Each part is explained below with its known weaknesses; for the bigger picture see how cipher suites work.

Key exchange: ECDHE_PSK. A pre-shared key authenticates the peers and an ephemeral ECDHE share is combined with it, giving forward secrecy without certificates. The first ECDHE_PSK suites came in RFC 5489 (2009); AES-GCM and AES-CCM versions for TLS 1.2 followed in RFC 8442 (2018).

Encryption: RC4, a stream cipher whose keystream is measurably biased. AlFardan, Bernstein, Paterson, Poettering and Schuldt showed in 2013 that a secret such as a cookie can be recovered from enough encryptions of it, and RFC 7465 (2015) then prohibited RC4 suites outright: clients MUST NOT offer them and servers MUST NOT select them.

Integrity: HMAC-SHA1. SHA-1 collisions are practical (SHAttered, 2017), but HMAC does not rely on collision resistance, so HMAC-SHA1 record MACs are not considered broken; this suite's weak points lie elsewhere. When TLS 1.2 is negotiated, keys are derived with the SHA-256 PRF, which RFC 5246 (2008) applies to every cipher suite defined before it.

Why this rating

ssl.sh rating: Insecure. The reasons:

• Uses RC4, which RFC 7465 prohibits in all TLS versions because of practical biases in its keystream.

How ssl.sh rates cipher suites

Which TLS libraries support it

Support for TLS_ECDHE_PSK_WITH_RC4_128_SHA 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 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.

History and standards status

TLS_ECDHE_PSK_WITH_RC4_128_SHA (0xC0,0x33) is registered in the IANA TLS Cipher Suites registry with RFC 5489, “ECDHE_PSK Cipher Suites for Transport Layer Security (TLS)” (March 2009, Informational) as its specification. DTLS 1.2 (RFC 6347, January 2012) had already said RC4 MUST NOT be used with DTLS. RFC 7465 (2015) prohibits RC4 cipher suites in every TLS version: clients MUST NOT offer them and servers MUST NOT select them. The registry marks it D (discouraged), a value introduced by RFC 9847 (2025).

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:!ECDHE-PSK-RC4-SHA';

# 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:!ECDHE-PSK-RC4-SHA

How to test whether a server accepts it

Offer only TLS_ECDHE_PSK_WITH_RC4_128_SHA with openssl s_client; if the handshake completes, the server accepts it:

openssl s_client -connect example.com:443 -tls1_2 -cipher ECDHE-PSK-RC4-SHA </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_ECDHE_PSK_WITH_RC4_128_SHA 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.