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-rw-r--r-- | src/crypto/random_nz.c | 75 | ||||
-rw-r--r-- | src/include/ipxe/random_nz.h | 16 |
2 files changed, 91 insertions, 0 deletions
diff --git a/src/crypto/random_nz.c b/src/crypto/random_nz.c new file mode 100644 index 0000000..7b54aad --- /dev/null +++ b/src/crypto/random_nz.c @@ -0,0 +1,75 @@ +/* + * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +/** @file + * + * 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.) + */ + +#include <stddef.h> +#include <stdint.h> +#include <ipxe/rbg.h> +#include <ipxe/random_nz.h> + +/** + * Get random non-zero bytes + * + * @v data Output buffer + * @v len Length of output buffer + * @ret 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). + */ +int get_random_nz ( void *data, size_t len ) { + 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; +} diff --git a/src/include/ipxe/random_nz.h b/src/include/ipxe/random_nz.h new file mode 100644 index 0000000..6bb80d2 --- /dev/null +++ b/src/include/ipxe/random_nz.h @@ -0,0 +1,16 @@ +#ifndef _IPXE_RANDOM_NZ_H +#define _IPXE_RANDOM_NZ_H + +/** @file + * + * HMAC_DRBG algorithm + * + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include <stdint.h> + +extern int get_random_nz ( void *data, size_t len ); + +#endif /* _IPXE_RANDOM_NZ_H */ |