curl/docs/CIPHERS.md
Daniel Stenberg 78d6232f1f
gskit: remove
We remove support for building curl with gskit.

 - This is a niche TLS library, only running on some IBM systems
 - no regular curl contributors use this backend
 - no CI builds use or verify this backend
 - gskit, or the curl adaption for it, lacks many modern TLS features
   making it an inferior solution
 - build breakages in this code take weeks or more to get detected
 - fixing gskit code is mostly done "flying blind"

This removal has been advertized in DEPRECATED in Jan 2, 2023 and it has
been mentioned on the curl-library mailing list.

It could be brought back, this is not a ban. Given proper effort and
will, gskit support is welcome back into the curl TLS backend family.

Closes #11460
2023-08-07 20:57:48 +02:00

428 lines
10 KiB
Markdown

# Ciphers
With curl's options
[`CURLOPT_SSL_CIPHER_LIST`](https://curl.se/libcurl/c/CURLOPT_SSL_CIPHER_LIST.html)
and
[`--ciphers`](https://curl.se/docs/manpage.html#--ciphers)
users can control which ciphers to consider when negotiating TLS connections.
TLS 1.3 ciphers are supported since curl 7.61 for OpenSSL 1.1.1+, and since
curl 7.85 for Schannel with options
[`CURLOPT_TLS13_CIPHERS`](https://curl.se/libcurl/c/CURLOPT_TLS13_CIPHERS.html)
and
[`--tls13-ciphers`](https://curl.se/docs/manpage.html#--tls13-ciphers)
. If you are using a different SSL backend you can try setting TLS 1.3 cipher
suites by using the respective regular cipher option.
The names of the known ciphers differ depending on which TLS backend that
libcurl was built to use. This is an attempt to list known cipher names.
## OpenSSL
(based on [OpenSSL docs](https://www.openssl.org/docs/manmaster/man1/openssl-ciphers.html))
When specifying multiple cipher names, separate them with colon (`:`).
### SSL3 cipher suites
`NULL-MD5`
`NULL-SHA`
`RC4-MD5`
`RC4-SHA`
`IDEA-CBC-SHA`
`DES-CBC3-SHA`
`DH-DSS-DES-CBC3-SHA`
`DH-RSA-DES-CBC3-SHA`
`DHE-DSS-DES-CBC3-SHA`
`DHE-RSA-DES-CBC3-SHA`
`ADH-RC4-MD5`
`ADH-DES-CBC3-SHA`
### TLS v1.0 cipher suites
`NULL-MD5`
`NULL-SHA`
`RC4-MD5`
`RC4-SHA`
`IDEA-CBC-SHA`
`DES-CBC3-SHA`
`DHE-DSS-DES-CBC3-SHA`
`DHE-RSA-DES-CBC3-SHA`
`ADH-RC4-MD5`
`ADH-DES-CBC3-SHA`
### AES cipher suites from RFC 3268, extending TLS v1.0
`AES128-SHA`
`AES256-SHA`
`DH-DSS-AES128-SHA`
`DH-DSS-AES256-SHA`
`DH-RSA-AES128-SHA`
`DH-RSA-AES256-SHA`
`DHE-DSS-AES128-SHA`
`DHE-DSS-AES256-SHA`
`DHE-RSA-AES128-SHA`
`DHE-RSA-AES256-SHA`
`ADH-AES128-SHA`
`ADH-AES256-SHA`
### SEED cipher suites from RFC 4162, extending TLS v1.0
`SEED-SHA`
`DH-DSS-SEED-SHA`
`DH-RSA-SEED-SHA`
`DHE-DSS-SEED-SHA`
`DHE-RSA-SEED-SHA`
`ADH-SEED-SHA`
### GOST cipher suites, extending TLS v1.0
`GOST94-GOST89-GOST89`
`GOST2001-GOST89-GOST89`
`GOST94-NULL-GOST94`
`GOST2001-NULL-GOST94`
### Elliptic curve cipher suites
`ECDHE-RSA-NULL-SHA`
`ECDHE-RSA-RC4-SHA`
`ECDHE-RSA-DES-CBC3-SHA`
`ECDHE-RSA-AES128-SHA`
`ECDHE-RSA-AES256-SHA`
`ECDHE-ECDSA-NULL-SHA`
`ECDHE-ECDSA-RC4-SHA`
`ECDHE-ECDSA-DES-CBC3-SHA`
`ECDHE-ECDSA-AES128-SHA`
`ECDHE-ECDSA-AES256-SHA`
`AECDH-NULL-SHA`
`AECDH-RC4-SHA`
`AECDH-DES-CBC3-SHA`
`AECDH-AES128-SHA`
`AECDH-AES256-SHA`
### TLS v1.2 cipher suites
`NULL-SHA256`
`AES128-SHA256`
`AES256-SHA256`
`AES128-GCM-SHA256`
`AES256-GCM-SHA384`
`DH-RSA-AES128-SHA256`
`DH-RSA-AES256-SHA256`
`DH-RSA-AES128-GCM-SHA256`
`DH-RSA-AES256-GCM-SHA384`
`DH-DSS-AES128-SHA256`
`DH-DSS-AES256-SHA256`
`DH-DSS-AES128-GCM-SHA256`
`DH-DSS-AES256-GCM-SHA384`
`DHE-RSA-AES128-SHA256`
`DHE-RSA-AES256-SHA256`
`DHE-RSA-AES128-GCM-SHA256`
`DHE-RSA-AES256-GCM-SHA384`
`DHE-DSS-AES128-SHA256`
`DHE-DSS-AES256-SHA256`
`DHE-DSS-AES128-GCM-SHA256`
`DHE-DSS-AES256-GCM-SHA384`
`ECDHE-RSA-AES128-SHA256`
`ECDHE-RSA-AES256-SHA384`
`ECDHE-RSA-AES128-GCM-SHA256`
`ECDHE-RSA-AES256-GCM-SHA384`
`ECDHE-ECDSA-AES128-SHA256`
`ECDHE-ECDSA-AES256-SHA384`
`ECDHE-ECDSA-AES128-GCM-SHA256`
`ECDHE-ECDSA-AES256-GCM-SHA384`
`ADH-AES128-SHA256`
`ADH-AES256-SHA256`
`ADH-AES128-GCM-SHA256`
`ADH-AES256-GCM-SHA384`
`AES128-CCM`
`AES256-CCM`
`DHE-RSA-AES128-CCM`
`DHE-RSA-AES256-CCM`
`AES128-CCM8`
`AES256-CCM8`
`DHE-RSA-AES128-CCM8`
`DHE-RSA-AES256-CCM8`
`ECDHE-ECDSA-AES128-CCM`
`ECDHE-ECDSA-AES256-CCM`
`ECDHE-ECDSA-AES128-CCM8`
`ECDHE-ECDSA-AES256-CCM8`
### Camellia HMAC-Based cipher suites from RFC 6367, extending TLS v1.2
`ECDHE-ECDSA-CAMELLIA128-SHA256`
`ECDHE-ECDSA-CAMELLIA256-SHA384`
`ECDHE-RSA-CAMELLIA128-SHA256`
`ECDHE-RSA-CAMELLIA256-SHA384`
### TLS 1.3 cipher suites
(Note these ciphers are set with `CURLOPT_TLS13_CIPHERS` and `--tls13-ciphers`)
`TLS_AES_256_GCM_SHA384`
`TLS_CHACHA20_POLY1305_SHA256`
`TLS_AES_128_GCM_SHA256`
`TLS_AES_128_CCM_8_SHA256`
`TLS_AES_128_CCM_SHA256`
## WolfSSL
`RC4-SHA`,
`RC4-MD5`,
`DES-CBC3-SHA`,
`AES128-SHA`,
`AES256-SHA`,
`NULL-SHA`,
`NULL-SHA256`,
`DHE-RSA-AES128-SHA`,
`DHE-RSA-AES256-SHA`,
`DHE-PSK-AES256-GCM-SHA384`,
`DHE-PSK-AES128-GCM-SHA256`,
`PSK-AES256-GCM-SHA384`,
`PSK-AES128-GCM-SHA256`,
`DHE-PSK-AES256-CBC-SHA384`,
`DHE-PSK-AES128-CBC-SHA256`,
`PSK-AES256-CBC-SHA384`,
`PSK-AES128-CBC-SHA256`,
`PSK-AES128-CBC-SHA`,
`PSK-AES256-CBC-SHA`,
`DHE-PSK-AES128-CCM`,
`DHE-PSK-AES256-CCM`,
`PSK-AES128-CCM`,
`PSK-AES256-CCM`,
`PSK-AES128-CCM-8`,
`PSK-AES256-CCM-8`,
`DHE-PSK-NULL-SHA384`,
`DHE-PSK-NULL-SHA256`,
`PSK-NULL-SHA384`,
`PSK-NULL-SHA256`,
`PSK-NULL-SHA`,
`HC128-MD5`,
`HC128-SHA`,
`HC128-B2B256`,
`AES128-B2B256`,
`AES256-B2B256`,
`RABBIT-SHA`,
`NTRU-RC4-SHA`,
`NTRU-DES-CBC3-SHA`,
`NTRU-AES128-SHA`,
`NTRU-AES256-SHA`,
`AES128-CCM-8`,
`AES256-CCM-8`,
`ECDHE-ECDSA-AES128-CCM`,
`ECDHE-ECDSA-AES128-CCM-8`,
`ECDHE-ECDSA-AES256-CCM-8`,
`ECDHE-RSA-AES128-SHA`,
`ECDHE-RSA-AES256-SHA`,
`ECDHE-ECDSA-AES128-SHA`,
`ECDHE-ECDSA-AES256-SHA`,
`ECDHE-RSA-RC4-SHA`,
`ECDHE-RSA-DES-CBC3-SHA`,
`ECDHE-ECDSA-RC4-SHA`,
`ECDHE-ECDSA-DES-CBC3-SHA`,
`AES128-SHA256`,
`AES256-SHA256`,
`DHE-RSA-AES128-SHA256`,
`DHE-RSA-AES256-SHA256`,
`ECDH-RSA-AES128-SHA`,
`ECDH-RSA-AES256-SHA`,
`ECDH-ECDSA-AES128-SHA`,
`ECDH-ECDSA-AES256-SHA`,
`ECDH-RSA-RC4-SHA`,
`ECDH-RSA-DES-CBC3-SHA`,
`ECDH-ECDSA-RC4-SHA`,
`ECDH-ECDSA-DES-CBC3-SHA`,
`AES128-GCM-SHA256`,
`AES256-GCM-SHA384`,
`DHE-RSA-AES128-GCM-SHA256`,
`DHE-RSA-AES256-GCM-SHA384`,
`ECDHE-RSA-AES128-GCM-SHA256`,
`ECDHE-RSA-AES256-GCM-SHA384`,
`ECDHE-ECDSA-AES128-GCM-SHA256`,
`ECDHE-ECDSA-AES256-GCM-SHA384`,
`ECDH-RSA-AES128-GCM-SHA256`,
`ECDH-RSA-AES256-GCM-SHA384`,
`ECDH-ECDSA-AES128-GCM-SHA256`,
`ECDH-ECDSA-AES256-GCM-SHA384`,
`CAMELLIA128-SHA`,
`DHE-RSA-CAMELLIA128-SHA`,
`CAMELLIA256-SHA`,
`DHE-RSA-CAMELLIA256-SHA`,
`CAMELLIA128-SHA256`,
`DHE-RSA-CAMELLIA128-SHA256`,
`CAMELLIA256-SHA256`,
`DHE-RSA-CAMELLIA256-SHA256`,
`ECDHE-RSA-AES128-SHA256`,
`ECDHE-ECDSA-AES128-SHA256`,
`ECDH-RSA-AES128-SHA256`,
`ECDH-ECDSA-AES128-SHA256`,
`ECDHE-RSA-AES256-SHA384`,
`ECDHE-ECDSA-AES256-SHA384`,
`ECDH-RSA-AES256-SHA384`,
`ECDH-ECDSA-AES256-SHA384`,
`ECDHE-RSA-CHACHA20-POLY1305`,
`ECDHE-ECDSA-CHACHA20-POLY1305`,
`DHE-RSA-CHACHA20-POLY1305`,
`ECDHE-RSA-CHACHA20-POLY1305-OLD`,
`ECDHE-ECDSA-CHACHA20-POLY1305-OLD`,
`DHE-RSA-CHACHA20-POLY1305-OLD`,
`ADH-AES128-SHA`,
`QSH`,
`RENEGOTIATION-INFO`,
`IDEA-CBC-SHA`,
`ECDHE-ECDSA-NULL-SHA`,
`ECDHE-PSK-NULL-SHA256`,
`ECDHE-PSK-AES128-CBC-SHA256`,
`PSK-CHACHA20-POLY1305`,
`ECDHE-PSK-CHACHA20-POLY1305`,
`DHE-PSK-CHACHA20-POLY1305`,
`EDH-RSA-DES-CBC3-SHA`,
## Schannel
Schannel allows the enabling and disabling of encryption algorithms, but not
specific cipher suites, prior to TLS 1.3. The algorithms are
[defined](https://docs.microsoft.com/windows/desktop/SecCrypto/alg-id) by
Microsoft.
The algorithms below are for TLS 1.2 and earlier. TLS 1.3 is covered in the
next section.
There is also the case that the selected algorithm is not supported by the
protocol or does not match the ciphers offered by the server during the SSL
negotiation. In this case curl will return error
`CURLE_SSL_CONNECT_ERROR (35) SEC_E_ALGORITHM_MISMATCH`
and the request will fail.
`CALG_MD2`,
`CALG_MD4`,
`CALG_MD5`,
`CALG_SHA`,
`CALG_SHA1`,
`CALG_MAC`,
`CALG_RSA_SIGN`,
`CALG_DSS_SIGN`,
`CALG_NO_SIGN`,
`CALG_RSA_KEYX`,
`CALG_DES`,
`CALG_3DES_112`,
`CALG_3DES`,
`CALG_DESX`,
`CALG_RC2`,
`CALG_RC4`,
`CALG_SEAL`,
`CALG_DH_SF`,
`CALG_DH_EPHEM`,
`CALG_AGREEDKEY_ANY`,
`CALG_HUGHES_MD5`,
`CALG_SKIPJACK`,
`CALG_TEK`,
`CALG_CYLINK_MEK`,
`CALG_SSL3_SHAMD5`,
`CALG_SSL3_MASTER`,
`CALG_SCHANNEL_MASTER_HASH`,
`CALG_SCHANNEL_MAC_KEY`,
`CALG_SCHANNEL_ENC_KEY`,
`CALG_PCT1_MASTER`,
`CALG_SSL2_MASTER`,
`CALG_TLS1_MASTER`,
`CALG_RC5`,
`CALG_HMAC`,
`CALG_TLS1PRF`,
`CALG_HASH_REPLACE_OWF`,
`CALG_AES_128`,
`CALG_AES_192`,
`CALG_AES_256`,
`CALG_AES`,
`CALG_SHA_256`,
`CALG_SHA_384`,
`CALG_SHA_512`,
`CALG_ECDH`,
`CALG_ECMQV`,
`CALG_ECDSA`,
`CALG_ECDH_EPHEM`,
As of curl 7.77.0, you can also pass `SCH_USE_STRONG_CRYPTO` as a cipher name
to [constrain the set of available ciphers as specified in the Schannel
documentation](https://docs.microsoft.com/en-us/windows/win32/secauthn/tls-cipher-suites-in-windows-server-2022).
Note that the supported ciphers in this case follow the OS version, so if you
are running an outdated OS you might still be supporting weak ciphers.
### TLS 1.3 cipher suites
You can set TLS 1.3 ciphers for Schannel by using `CURLOPT_TLS13_CIPHERS` or
`--tls13-ciphers` with the names below.
If TLS 1.3 cipher suites are set then libcurl will add or restrict Schannel TLS
1.3 algorithms automatically. Essentially, libcurl is emulating support for
individual TLS 1.3 cipher suites since Schannel does not support it directly.
`TLS_AES_256_GCM_SHA384`
`TLS_AES_128_GCM_SHA256`
`TLS_CHACHA20_POLY1305_SHA256`
`TLS_AES_128_CCM_8_SHA256`
`TLS_AES_128_CCM_SHA256`
Note if you set TLS 1.3 ciphers without also setting the minimum TLS version to
1.3 then it's possible Schannel may negotiate an earlier TLS version and cipher
suite if your libcurl and OS settings allow it. You can set the minimum TLS
version by using `CURLOPT_SSLVERSION` or `--tlsv1.3`.
## BearSSL
BearSSL ciphers can be specified by either the OpenSSL name (`ECDHE-RSA-AES128-GCM-SHA256`) or the IANA name (`TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256`).
Since BearSSL 0.1:
`DES-CBC3-SHA`
`AES128-SHA`
`AES256-SHA`
`AES128-SHA256`
`AES256-SHA256`
`AES128-GCM-SHA256`
`AES256-GCM-SHA384`
`ECDH-ECDSA-DES-CBC3-SHA`
`ECDH-ECDSA-AES128-SHA`
`ECDH-ECDSA-AES256-SHA`
`ECDHE-ECDSA-DES-CBC3-SHA`
`ECDHE-ECDSA-AES128-SHA`
`ECDHE-ECDSA-AES256-SHA`
`ECDH-RSA-DES-CBC3-SHA`
`ECDH-RSA-AES128-SHA`
`ECDH-RSA-AES256-SHA`
`ECDHE-RSA-DES-CBC3-SHA`
`ECDHE-RSA-AES128-SHA`
`ECDHE-RSA-AES256-SHA`
`ECDHE-ECDSA-AES128-SHA256`
`ECDHE-ECDSA-AES256-SHA384`
`ECDH-ECDSA-AES128-SHA256`
`ECDH-ECDSA-AES256-SHA384`
`ECDHE-RSA-AES128-SHA256`
`ECDHE-RSA-AES256-SHA384`
`ECDH-RSA-AES128-SHA256`
`ECDH-RSA-AES256-SHA384`
`ECDHE-ECDSA-AES128-GCM-SHA256`
`ECDHE-ECDSA-AES256-GCM-SHA384`
`ECDH-ECDSA-AES128-GCM-SHA256`
`ECDH-ECDSA-AES256-GCM-SHA384`
`ECDHE-RSA-AES128-GCM-SHA256`
`ECDHE-RSA-AES256-GCM-SHA384`
`ECDH-RSA-AES128-GCM-SHA256`
`ECDH-RSA-AES256-GCM-SHA384`
Since BearSSL 0.2:
`ECDHE-RSA-CHACHA20-POLY1305`
`ECDHE-ECDSA-CHACHA20-POLY1305`
Since BearSSL 0.6:
`AES128-CCM`
`AES256-CCM`
`AES128-CCM8`
`AES256-CCM8`
`ECDHE-ECDSA-AES128-CCM`
`ECDHE-ECDSA-AES256-CCM`
`ECDHE-ECDSA-AES128-CCM8`
`ECDHE-ECDSA-AES256-CCM8`