random_nz.c File Reference

Random non-zero bytes. More...

#include <stddef.h>
#include <stdint.h>
#include <ipxe/rbg.h>
#include <ipxe/random_nz.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
int	get_random_nz (void *data, size_t len)
	Get random non-zero bytes. More...

Detailed Description

Random non-zero bytes.

The RSA algorithm requires the generation of random non-zero bytes, i.e. bytes in the range [0x01,0xff].

This algorithm is designed to comply with ANS X9.82 Part 1-2006 Section 9.2.1. This standard is not freely available, but most of the text appears to be shared with NIST SP 800-90, which can be downloaded from

http://csrc.nist.gov/publications/nistpubs/800-90/SP800-90revised_March2007.pdf

Where possible, references are given to both documents. In the case of any disagreement, ANS X9.82 takes priority over NIST SP 800-90. (In particular, note that some algorithms that are Approved by NIST SP 800-90 are not Approved by ANS X9.82.)

Definition in file random_nz.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

get_random_nz()

int get_random_nz	(	void *	data,
		size_t	len
	)

Get random non-zero bytes.

Parameters

data	Output buffer
len	Length of output buffer

Return values

rc	Return status code

This algorithm is designed to be isomorphic to the Simple Discard Method described in ANS X9.82 Part 1-2006 Section 9.2.1 (NIST SP 800-90 Section B.5.1.1).

Definition at line 62 of file random_nz.c.

                                             {
        uint8_t *bytes = data;
        int rc;

        while ( len ) {

                /* Generate random byte */
                if ( ( rc = rbg_generate ( NULL, 0, 0, bytes, 1 ) ) != 0 )
                        return rc;

                /* Move to next byte if this byte is acceptable */
                if ( *bytes != 0 ) {
                        bytes++;
                        len--;
                }
        }

        return 0;
}

References bytes, data, len, NULL, rbg_generate(), and rc.

Referenced by rsa_encrypt().