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gnutls_priority_init2(3) gnutls gnutls_priority_init2(3)
gnutls_priority_init2 - API function
int gnutls_priority_init2(gnutls_priority_t * priority_cache, const
char * priorities, const char ** err_pos, unsigned flags);
gnutls_priority_t * priority_cache
is a gnutls_prioritity_t type.
const char * priorities
is a string describing priorities (may be NULL)
const char ** err_pos
In case of an error this will have the position in the
string the error occurred
zero or GNUTLS_PRIORITY_INIT_DEF_APPEND
Sets priorities for the ciphers, key exchange methods, and macs. The
priority_cache should be deinitialized using gnutls_priority_deinit().
The priorities option allows you to specify a colon separated list of
the cipher priorities to enable. Some keywords are defined to provide
quick access to common preferences.
When flags is set to GNUTLS_PRIORITY_INIT_DEF_APPEND then the
priorities specified will be appended to the default options.
Unless there is a special need, use the "NORMAL" keyword to apply a
reasonable security level, or "NORMAL:%COMPAT" for compatibility.
"PERFORMANCE" means all the "secure" ciphersuites are enabled, limited
to 128 bit ciphers and sorted by terms of speed performance.
"LEGACY" the NORMAL settings for GnuTLS 3.2.x or earlier. There is no
verification profile set, and the allowed DH primes are considered weak
"NORMAL" means all "secure" ciphersuites. The 256-bit ciphers are
included as a fallback only. The ciphers are sorted by security
"PFS" means all "secure" ciphersuites that support perfect forward
secrecy. The 256-bit ciphers are included as a fallback only. The
ciphers are sorted by security margin.
"SECURE128" means all "secure" ciphersuites of security level 128-bit
"SECURE192" means all "secure" ciphersuites of security level 192-bit
"SUITEB128" means all the NSA SuiteB ciphersuites with security level
"SUITEB192" means all the NSA SuiteB ciphersuites with security level
"NONE" means nothing is enabled. This disables everything, including
"@KEYWORD1,KEYWORD2,..." The system administrator imposed settings.
The provided keyword(s) will be expanded from a configuration-time
provided file - default is: /usr/local/etc/gnutls/default-priorities.
Any attributes that follow it, will be appended to the expanded string.
If multiple keywords are provided, separated by commas, then the first
keyword that exists in the configuration file will be used. At least
one of the keywords must exist, or this function will return an error.
Typical usage would be to specify an application specified keyword
first, followed by "SYSTEM" as a default fallback. e.g., " LIBVIRT
,SYSTEM:!-VERS-SSL3.0" will first try to find a config file entry
matching "LIBVIRT", but if that does not exist will use the entry for
"SYSTEM". If "SYSTEM" does not exist either, an error will be returned.
In all cases, the SSL3.0 protocol will be disabled. The system priority
file entries should be formatted as "KEYWORD=VALUE", e.g.,
Special keywords are "!", "-" and "+". "!" or "-" appended with an
algorithm will remove this algorithm. "+" appended with an algorithm
will add this algorithm.
Check the GnuTLS manual section "Priority strings" for detailed
"NORMAL:+ARCFOUR-128" means normal ciphers plus ARCFOUR-128.
"SECURE128:-VERS-SSL3.0" means that only secure ciphers are and
enabled, SSL3.0 is disabled.
Note that "NORMAL:%COMPAT" is the most compatible mode.
A NULL priorities string indicates the default priorities to be used
(this is available since GnuTLS 3.3.0).
On syntax error GNUTLS_E_INVALID_REQUEST is returned, GNUTLS_E_SUCCESS
on success, or an error code.
Report bugs to <firstname.lastname@example.org>.
Home page: https://www.gnutls.org
Copyright (C) 2001-2019 Free Software Foundation, Inc., and others.
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.
The full documentation for gnutls is maintained as a Texinfo manual.
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gnutls 3.6.9 gnutls_priority_init2(3)