Man Linux: Main Page and Category List


       gnutls_priority_init  - Sets priorities for the cipher suites supported
       by gnutls.


       #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 structure.

       const char * priorities
                   is a string describing priorities

       const char ** err_pos
                   In  case  of  an  error  this will have the position in the
                   string the error occured


       Sets priorities  for  the  ciphers,  key  exchange  methods,  macs  and
       compression  methods.  This  is  to avoid using the gnutls_*_priority()

       The priorities option allows you to specify a semi-colon separated list
       of the cipher priorities to enable.

       Unless  the  first keyword is "NONE" the defaults (in preference order)
       are for TLS protocols TLS1.1, TLS1.0, SSL3.0; for compression NULL; for
       certificate types X.509, OpenPGP.

       For key exchange algorithms when in NORMAL or SECURE levels the perfect
       forward secrecy algorithms take precendence of the other protocols.  In
       all cases all the supported key exchange algorithms are enabled (except
       for the RSA-EXPORT which is only enabled in EXPORT level).

       Note that although one can select very long  key  sizes  (such  as  256
       bits)  for  symmetric  algorithms,  to  actually  increase security the
       public key algorithms have to use longer key sizes as well.

       For all the current available algorithms and protocols use  "gnutls-cli
       -l" to get a listing.


       Some   keywords   are   defined  to  provide  quick  access  to  common

       "PERFORMANCE" means all the "secure" ciphersuites are enabled,  limited
       to 128 bit ciphers and sorted by terms of speed performance.

       "NORMAL"  means  all  "secure"  ciphersuites.  The  256-bit ciphers are
       included as a fallback  only.   The  ciphers  are  sorted  by  security

       "SECURE128"  means  all  "secure"  ciphersuites  with ciphers up to 128
       bits, sorted by security margin.

       "SECURE256" means all  "secure"  ciphersuites  including  the  256  bit
       ciphers, sorted by security margin.

       "EXPORT" means all ciphersuites are enabled, including the low-security
       40 bit ciphers.

       "NONE" means nothing is enabled.   This  disables  even  protocols  and
       compression methods.


       "!" or "-" appended with an algorithm will remove this algorithm.

       "+" appended with an algorithm will add this algorithm.

       "%COMPAT" will enable compatibility features for a server.

       "%SSL3_RECORD_VERSION"  will use SSL3.0 record version in client hello.

       "%VERIFY_ALLOW_SIGN_RSA_MD5"   will   allow   RSA-MD5   signatures   in
       certificate chains.

       "%VERIFY_ALLOW_X509_V1_CA_CRT" will allow V1 CAs in chains.


       To avoid collisions in order to specify a compression algorithm in this
       string you have to prefix  it  with  "COMP-",  protocol  versions  with
       "VERS-" and certificate types with "CTYPE-". All other algorithms don’t
       need a prefix.


       "NORMAL:!AES-128-CBC" means normal ciphers except for AES-128.

       "EXPORT:!VERS-TLS1.0:+COMP-DEFLATE"  means  that  export  ciphers   are
       enabled, TLS 1.0 is disabled, and libz compression enabled.

       "NONE:+VERS-TLS1.0:+AES-128-CBC:+RSA:+SHA1:+COMP-NULL",       "NORMAL",


       On syntax error GNUTLS_E_INVALID_REQUEST is returned,  GNUTLS_E_SUCCESS
       on success, or an error code.


       Report    bugs    to    <>.     GnuTLS   home   page: General help  using  GNU  software:


       Copyright © 2008 Free Software Foundation.
       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 info and gnutls programs are properly installed  at  your  site,
       the command

              info gnutls

       should give you access to the complete manual.