It takes input from stdin, and outputs statistics to stderr, optionally echoing blocks that passed the FIPS tests to stdout (when operating in pipe mode). Errors are sent to stderr.

At startup, rngtest will trow away the first 32 bits of data when operating in pipe mode. It will use the next 32 bits of data to bootstrap the FIPS tests (even when not operating in pipe mode). These bits are not tested for randomness.

Statistics are dumped to stderr when the program exits.

-p, --pipe

Enable pipe mode. All data blocks that pass the FIPS tests are echoed to stdout, and rngtest operates in silent mode.

-c n, --blockcount=n (default: 0)

Exit after processing n input blocks, if n is not zero.

-b n, --blockstats=n (default: 0)

Dump statistics every n blocks, if n is not zero.

-t n, --timedstats=n (default: 0)

Dump statistics every n secods, if n is not zero.

-?, --help

Give a short summary of all program options.

-V, --version

Print program version

FIPS 140-2 successes and FIPS 140-2 failures counts the number of 20000-bit blocks either accepted or rejected by the FIPS 140-2 tests. The other statistics show a breakdown of the FIPS 140-2 failures by FIPS 140-2 test. See the FIPS 140-2 document for more information (note that these tests are defined on FIPS 140-1 and FIPS 140-2 errata of 2001-10-10. They were removed in FIPS 140-2 errata of 2002-12-03).

The speed statistics are taken for every 20000-bit block trasferred or processed.

0 if no errors happen, and no blocks fail the FIPS tests.

1 if no errors happen, but at least one block fails the FIPS tests.

10 if there are problems with the parameters.

11 if an input/output error happens.

12 if an operating system or resource starvation error happens.