Go to main content

man pages section 7: Standards, Environments, Macros, Character Sets, and Miscellany

Exit Print View

Updated: Thursday, June 13, 2019

crypto (7erl)


crypto - The Crypto Application


Please see following description for synopsis


Erlang Application Definition                                        crypto(7)

       crypto - The Crypto Application

       The  purpose  of  the Crypto application is to provide an Erlang API to
       cryptographic functions, see crypto(3). Note  that  the  API  is  on  a
       fairly  low level and there are some corresponding API functions avail-
       able in public_key(3), on a higher abstraction  level,  that  uses  the
       crypto application in its implementation.

       The  current  crypto  implementation  uses  nifs  to interface OpenSSLs
       crypto library and may work with limited functionality with as old ver-
       sions  as  OpenSSL  0.9.8c. FIPS mode support requires at least version
       1.0.1 and a FIPS capable OpenSSL installation.  We  recommend  using  a
       version  that  is officially supported by the OpenSSL project. API com-
       patible backends like LibreSSL should also work.

       Source releases of OpenSSL can be downloaded from the  OpenSSL  project
       home page, or mirror sites listed there.

       The  following  configuration  parameters  are  defined  for the crypto
       application. See app(3) for more information about configuration param-

         fips_mode = boolean():
           Specifies  whether  to  run  crypto in FIPS mode. This setting will
           take effect when  the  nif  module  is  loaded.  If  FIPS  mode  is
           requested but not available at run time the nif module and thus the
           crypto module will fail to load. This mechanism prevents the  acci-
           dental use of non-validated algorithms.

         rand_cache_size = integer():
           Sets     the     cache     size     in     bytes    to    use    by
           crypto:rand_seed_alg(crypto_cache)                              and
           crypto:rand_seed_alg_s(crypto_cache). This parameter is read when a
           seed function is called, and then kept in generators state  object.
           It  has  a  rather  small default value that causes reads of strong
           random bytes about once per hundred calls for a random  value.  The
           set  value is rounded up to an integral number of words of the size
           these seed functions use.


Ericsson AB                       crypto 4.3                         crypto(7)