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NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | EXAMPLES | RETURNS | REPORTING BUGS | COPYRIGHT | SEE ALSO | COLOPHON |
gnutls_priority_init(3) gnutls gnutls_priority_init(3)
gnutls_priority_init - API function
#include <gnutls/gnutls.h>
int gnutls_priority_init(gnutls_priority_t * priority_cache, const
char * priorities, const char ** err_pos);
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
Sets priorities for the ciphers, key exchange methods, macs and
compression methods. 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.
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 today.
"NORMAL" means all "secure" ciphersuites. The 256-bit ciphers are
included as a fallback only. The ciphers are sorted by security
margin.
"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
or more.
"SECURE192" means all "secure" ciphersuites of security level 192-bit
or more.
"SUITEB128" means all the NSA SuiteB ciphersuites with security level
of 128.
"SUITEB192" means all the NSA SuiteB ciphersuites with security level
of 192.
"NONE" means nothing is enabled. This disables even protocols and
compression methods.
"@KEYWORD1,KEYWORD2,..." The system administrator imposed settings.
The provided keyword(s) will be expanded from a configuration-time
provided file - default is: /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., "SYSTEM=NORMAL:+ARCFOUR-128".
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
information.
"NONE:+VERS-TLS-ALL:+MAC-ALL:+RSA:+AES-128-CBC:+SIGN-ALL:+COMP-NULL"
"NORMAL:+ARCFOUR-128" means normal ciphers plus ARCFOUR-128.
"SECURE128:-VERS-SSL3.0:+COMP-DEFLATE" means that only secure ciphers
are enabled, SSL3.0 is disabled, and libz compression enabled.
"NONE:+VERS-TLS-ALL:+AES-128-CBC:+RSA:+SHA1:+COMP-NULL:+SIGN-RSA-SHA1",
"NONE:+VERS-TLS-ALL:+AES-128-CBC:+ECDHE-RSA:+SHA1:+COMP-NULL:+SIGN-RSA-SHA1:+CURVE-SECP256R1",
"SECURE256:+SECURE128",
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 <bugs@gnutls.org>.
Home page: http://www.gnutls.org
Copyright © 2001-2017 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.
If the /usr/share/doc/gnutls/ directory does not contain the HTML
form visit
http://www.gnutls.org/manual/
This page is part of the GnuTLS (GnuTLS Transport Layer Security
Library) project. Information about the project can be found at
⟨http://www.gnutls.org/⟩. If you have a bug report for this manual
page, send it to bugs@gnutls.org.. This page was obtained from the
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⟨http://www.gnutls.org/download.html⟩ on 2017-07-05. If you discover
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COLOPHON (which is not part of the original manual page), send a mail
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gnutls 3.5.9 gnutls_priority_init(3)