crypto - The Crypto Application
The purpose of the Crypto application is to provide an Erlang API to
cryptographic functions, see crypto(3erl). Note that the API is on a
fairly low level and there are some corresponding API functions available in
public_key(3erl), 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 versions 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 compatible backends like LibreSSL should
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(3erl) for more information about configuration parameters.
- 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 accidental use of non-validated
- rand_cache_size = integer():
- Sets the cache size in bytes to use by
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