The BC FIPS provider.

If no SecureRandom has been specified using CryptoServicesRegistrar.setSecureRandom() the provider class will generate a FIPS compliant DRBG based on SHA-512. It is also possible to configure the DRBG by passing a string as a constructor argument to the provider via code, or the java.security configuration file.

At the moment the configuration string is limited to setting the DRBG.The configuration string must always start with "C:" and finish with "ENABLE{ALL};". The command for setting the actual DRBG type is DEFRND so a configuration string requesting the use of a SHA1 DRBG would look like:

        C:DEFRND[SHA1];ENABLE{ALL};
    

Possible values for the DRBG type are "SHA1", "SHA224", "SHA256", "SHA384", "SHA512", "SHA512(224)", "SHA512(256)", "HMACrovRandSHA1", "HMACSHA224", "HMACSHA256", "HMACSHA384", "HMACSHA512", "HMACSHA512(224)", "HMACSHA512(256)", "CTRAES128", "CTRAES192", CTRAES256", and "CTRDESEDE".

The default DRBG is configured to be prediction resistant. In situations where the amount of entropy is constrained the default DRBG can be configured to use an entropy pool based on a SHA-512 SP 800-90A DRBG. To configure this use:

        C:HYBRID;ENABLE{ALL};
    

or include the string "HYBRID;" in the previous command string setting the DRBG. After initial seeding the entropy pool will start a reseeding thread which it will begin polling once 20 samples have been taken since the last seeding and will do a reseed as soon as new entropy bytes are returned.