diff options
Diffstat (limited to 'doc/doc-docbook')
| -rw-r--r-- | doc/doc-docbook/spec.xfpt | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 7ae09cfbe..daaf0032c 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -27417,7 +27417,10 @@ the size of the generated prime, so it might still be too large. .oindex "&%tls_require_ciphers%&" "OpenSSL" There is a function in the OpenSSL library that can be passed a list of cipher suites before the cipher negotiation takes place. This specifies which ciphers -are acceptable. The list is colon separated and may contain names like +.new +are acceptable for TLS versions prior to 1.3. +.wen +The list is colon separated and may contain names like DES-CBC3-SHA. Exim passes the expanded value of &%tls_require_ciphers%& directly to this function call. Many systems will install the OpenSSL manual-pages, so you may have @@ -27482,6 +27485,18 @@ This example will prefer ECDSA-authenticated ciphers over RSA ones: tls_require_ciphers = ECDSA:RSA:!COMPLEMENTOFDEFAULT .endd +.new +For TLS version 1.3 the control available is less fine-grained +and Exim does not provide access to it at present. +The value of the &%tls_require_ciphers%& option is ignored when +TLS version 1.3 is negociated. + +As of writing the library default cipher suite list for TLSv1.3 is +.code +TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256 +.endd +.wen + .section "Requiring specific ciphers or other parameters in GnuTLS" &&& "SECTreqciphgnu" |