TLS_DH_RSA_WITH_DES_CBC_SHA

What each component means

A cipher suite names the algorithms a client and server agree on in one handshake. TLS_DH_RSA_WITH_DES_CBC_SHA combines DH key exchange, RSA authentication, DES-CBC 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: static (non-ephemeral) Diffie-Hellman. The server's DH public key is fixed in its certificate instead of being generated per handshake, so there is no forward secrecy, and the server needs a certificate that carries a DH key rather than an ordinary RSA or ECDSA key. The RSA in the name only says which algorithm the CA used to sign that certificate.

Encryption: single DES with a 56-bit key. The EFF's Deep Crack machine recovered a DES key by brute force in 56 hours in 1998, so this encryption offers no real protection today. RFC 5246 (2008) removed the DES suites from TLS 1.2.

Mode: CBC with MAC-then-encrypt. TLS 1.2 and earlier compute the HMAC over the plaintext, then pad and encrypt, so a receiver has to decrypt before it can check integrity. That ordering produced a long run of padding-oracle attacks: BEAST (CVE-2011-3389) against TLS 1.0's predictable IVs, Lucky Thirteen (CVE-2013-0169, 2013), which times the MAC check, and POODLE (CVE-2014-3566, 2014) against SSL 3.0's unchecked padding. RFC 9325 (2022) says CBC suites SHOULD NOT be used unless the encrypt_then_mac extension (RFC 7366) is also negotiated.

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.

Why this rating

ssl.sh rating: Insecure. The reasons:

• Uses single DES, whose 56-bit key can be brute-forced; RFC 5246 removed DES suites from TLS 1.2.

How ssl.sh rates cipher suites

Which TLS libraries support it

Support for TLS_DH_RSA_WITH_DES_CBC_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. None of them implements it.

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

The IANA registry entry for TLS_DH_RSA_WITH_DES_CBC_SHA (0x00,0x0F) now cites only RFC 8996, “Deprecating TLS 1.0 and TLS 1.1” (March 2021, Best Current Practice) and RFC 10015, “Deprecating Obsolete Key Exchange Methods in TLS 1.2 and DTLS 1.2” (July 2026, Standards Track). The TLS 1.2 specification, RFC 5246 (2008), removed the IDEA and DES suites, calling them deprecated. It can only be negotiated in SSL 3.0, TLS 1.0, TLS 1.1. RFC 7568 (2015) deprecated SSL 3.0 and RFC 8996 (2021) deprecated TLS 1.0 and TLS 1.1, so no protocol version still in good standing allows it. 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

OpenSSL 3.5 doesn't implement this suite, so stock Nginx and Apache httpd builds can't offer it and you don't need to disable it.

How to test whether a server accepts it

OpenSSL 3.5 cannot offer TLS_DH_RSA_WITH_DES_CBC_SHA, so openssl s_client can't test it directly; use a scanner that implements the suite itself.

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_RSA_WITH_DES_CBC_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.