Matt Caswell 9c1b8f17ce Avoid an infinite loop in BN_GF2m_mod_inv 3 months ago
..
asm da1c088f59 Copyright year updates 6 months ago
README.pod 706457b7bd Reorganize local header files 4 years ago
bn_add.c 605856d72c Update copyright year 3 years ago
bn_asm.c da1c088f59 Copyright year updates 6 months ago
bn_blind.c da1c088f59 Copyright year updates 6 months ago
bn_const.c c734058309 crypto/*: Fix various typos, repeated words, align some spelling to LDP. 1 year ago
bn_conv.c e077455e9e Stop raising ERR_R_MALLOC_FAILURE in most places 1 year ago
bn_ctx.c e077455e9e Stop raising ERR_R_MALLOC_FAILURE in most places 1 year ago
bn_depr.c 38fc02a708 Update copyright year 2 years ago
bn_dh.c 8020d79b40 Update copyright year 3 years ago
bn_div.c fecb3aae22 Update copyright year 1 year ago
bn_err.c d2399d8cd2 RSA keygen update: Raise an error if no prime candidate q is found. 1 year ago
bn_exp.c af0025fc40 bn: Properly error out if aliasing return value with modulus 5 months ago
bn_exp2.c fecb3aae22 Update copyright year 1 year ago
bn_gcd.c 0f7a3b0caa BN_gcd(): Avoid shifts of negative values 5 months ago
bn_gf2m.c 9c1b8f17ce Avoid an infinite loop in BN_GF2m_mod_inv 3 months ago
bn_intern.c e077455e9e Stop raising ERR_R_MALLOC_FAILURE in most places 1 year ago
bn_kron.c 706457b7bd Reorganize local header files 4 years ago
bn_lib.c da1c088f59 Copyright year updates 6 months ago
bn_local.h da1c088f59 Copyright year updates 6 months ago
bn_mod.c af0025fc40 bn: Properly error out if aliasing return value with modulus 5 months ago
bn_mont.c da1c088f59 Copyright year updates 6 months ago
bn_mpi.c 9311d0c471 Convert all {NAME}err() in crypto/ to their corresponding ERR_raise() call 3 years ago
bn_mul.c 1567a821a4 crypto: Fix various typos, repeated words, align some spelling to LDP. 1 year ago
bn_nist.c 990d9ff508 bn_nist: Fix strict-aliasing violations in little-endian optimizations 3 months ago
bn_ppc.c eae70100fa Revert "Revert "bn: Add fixed length (n=6), unrolled PPC Montgomery Multiplication"" 1 year ago
bn_prime.c d2f6e66d28 Improve FIPS RSA keygen performance. 1 year ago
bn_prime.h fd84b9c3e9 Fix copyright year issues 2 years ago
bn_prime.pl c37b947957 Add a local perl module to get year last changed 3 years ago
bn_print.c 706457b7bd Reorganize local header files 4 years ago
bn_rand.c da1c088f59 Copyright year updates 6 months ago
bn_recp.c da1c088f59 Copyright year updates 6 months ago
bn_rsa_fips186_4.c da1c088f59 Copyright year updates 6 months ago
bn_s390x.c da1c088f59 Copyright year updates 6 months ago
bn_shift.c 605856d72c Update copyright year 3 years ago
bn_sparc.c 52f7e44ec8 Split bignum code out of the sparcv9cap.c 2 years ago
bn_sqr.c 706457b7bd Reorganize local header files 4 years ago
bn_sqrt.c fecb3aae22 Update copyright year 1 year ago
bn_srp.c 3c2bdd7df9 Update copyright year 3 years ago
bn_word.c 706457b7bd Reorganize local header files 4 years ago
bn_x931p.c 5cbd2ea3f9 add zero strenght arguments to BN and RAND RNG calls 2 years ago
build.info 4209ce68d8 Revert "Fix Timing Oracle in RSA decryption" 1 year ago
rsaz_exp.c da1c088f59 Copyright year updates 6 months ago
rsaz_exp.h 6d702cebfc Add an extra reduction step to RSAZ mod_exp implementations 1 year ago
rsaz_exp_x2.c da1c088f59 Copyright year updates 6 months ago

README.pod

=pod

=head1 NAME

bn_mul_words, bn_mul_add_words, bn_sqr_words, bn_div_words,
bn_add_words, bn_sub_words, bn_mul_comba4, bn_mul_comba8,
bn_sqr_comba4, bn_sqr_comba8, bn_cmp_words, bn_mul_normal,
bn_mul_low_normal, bn_mul_recursive, bn_mul_part_recursive,
bn_mul_low_recursive, bn_sqr_normal, bn_sqr_recursive,
bn_expand, bn_wexpand, bn_expand2, bn_fix_top, bn_check_top,
bn_print, bn_dump, bn_set_max, bn_set_high, bn_set_low - BIGNUM
library internal functions

=head1 SYNOPSIS

#include

BN_ULONG bn_mul_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w);
BN_ULONG bn_mul_add_words(BN_ULONG *rp, BN_ULONG *ap, int num,
BN_ULONG w);
void bn_sqr_words(BN_ULONG *rp, BN_ULONG *ap, int num);
BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d);
BN_ULONG bn_add_words(BN_ULONG *rp, BN_ULONG *ap, BN_ULONG *bp,
int num);
BN_ULONG bn_sub_words(BN_ULONG *rp, BN_ULONG *ap, BN_ULONG *bp,
int num);

void bn_mul_comba4(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b);
void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b);
void bn_sqr_comba4(BN_ULONG *r, BN_ULONG *a);
void bn_sqr_comba8(BN_ULONG *r, BN_ULONG *a);

int bn_cmp_words(BN_ULONG *a, BN_ULONG *b, int n);

void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b,
int nb);
void bn_mul_low_normal(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n);
void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
int dna, int dnb, BN_ULONG *tmp);
void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b,
int n, int tna, int tnb, BN_ULONG *tmp);
void bn_mul_low_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b,
int n2, BN_ULONG *tmp);

void bn_sqr_normal(BN_ULONG *r, BN_ULONG *a, int n, BN_ULONG *tmp);
void bn_sqr_recursive(BN_ULONG *r, BN_ULONG *a, int n2, BN_ULONG *tmp);

void mul(BN_ULONG r, BN_ULONG a, BN_ULONG w, BN_ULONG c);
void mul_add(BN_ULONG r, BN_ULONG a, BN_ULONG w, BN_ULONG c);
void sqr(BN_ULONG r0, BN_ULONG r1, BN_ULONG a);

BIGNUM *bn_expand(BIGNUM *a, int bits);
BIGNUM *bn_wexpand(BIGNUM *a, int n);
BIGNUM *bn_expand2(BIGNUM *a, int n);
void bn_fix_top(BIGNUM *a);

void bn_check_top(BIGNUM *a);
void bn_print(BIGNUM *a);
void bn_dump(BN_ULONG *d, int n);
void bn_set_max(BIGNUM *a);
void bn_set_high(BIGNUM *r, BIGNUM *a, int n);
void bn_set_low(BIGNUM *r, BIGNUM *a, int n);

=head1 DESCRIPTION

This page documents the internal functions used by the OpenSSL
B implementation. They are described here to facilitate
debugging and extending the library. They are I to be used by
applications.

=head2 The BIGNUM structure

typedef struct bignum_st BIGNUM;

struct bignum_st
{
BN_ULONG *d; /* Pointer to an array of 'BN_BITS2' bit chunks. */
int top; /* Index of last used d +1. */
/* The next are internal book keeping for bn_expand. */
int dmax; /* Size of the d array. */
int neg; /* one if the number is negative */
int flags;
};


The integer value is stored in B, a malloc()ed array of words (B),
least significant word first. A B can be either 16, 32 or 64 bits
in size, depending on the 'number of bits' (B) specified in
C.

B is the size of the B array that has been allocated. B
is the number of words being used, so for a value of 4, bn.d[0]=4 and
bn.top=1. B is 1 if the number is negative. When a B is
B<0>, the B field can be B and B == B<0>.

B is a bit field of flags which are defined in C. The
flags begin with B. The macros BN_set_flags(b, n) and
BN_get_flags(b, n) exist to enable or fetch flag(s) B from B
structure B.

Various routines in this library require the use of temporary
B variables during their execution. Since dynamic memory
allocation to create Bs is rather expensive when used in
conjunction with repeated subroutine calls, the B structure is
used. This structure contains B Bs, see
L.

=head2 Low-level arithmetic operations

These functions are implemented in C and for several platforms in
assembly language:

bn_mul_words(B, B, B, B) operates on the B word
arrays B and B. It computes B * B, places the result
in B, and returns the high word (carry).

bn_mul_add_words(B, B, B, B) operates on the B
word arrays B and B. It computes B * B + B, places
the result in B, and returns the high word (carry).

bn_sqr_words(B, B, B) operates on the B word array
B and the 2*B word array B. It computes B * B
word-wise, and places the low and high bytes of the result in B.

bn_div_words(B, B, B) divides the two word number (B, B)
by B and returns the result.

bn_add_words(B, B, B, B) operates on the B word
arrays B, B and B. It computes B + B, places the
result in B, and returns the high word (carry).

bn_sub_words(B, B, B, B) operates on the B word
arrays B, B and B. It computes B - B, places the
result in B, and returns the carry (1 if B E B, 0
otherwise).

bn_mul_comba4(B, B, B) operates on the 4 word arrays B and
B and the 8 word array B. It computes B*B and places the
result in B.

bn_mul_comba8(B, B, B) operates on the 8 word arrays B and
B and the 16 word array B. It computes B*B and places the
result in B.

bn_sqr_comba4(B, B, B) operates on the 4 word arrays B and
B and the 8 word array B.

bn_sqr_comba8(B, B, B) operates on the 8 word arrays B and
B and the 16 word array B.

The following functions are implemented in C:

bn_cmp_words(B, B, B) operates on the B word arrays B
and B. It returns 1, 0 and -1 if B is greater than, equal and
less than B.

bn_mul_normal(B, B, B, B, B) operates on the B
word array B, the B word array B and the B+B word
array B. It computes B*B and places the result in B.

bn_mul_low_normal(B, B, B, B) operates on the B word
arrays B, B and B. It computes the B low words of
B*B and places the result in B.

bn_mul_recursive(B, B, B, B, B, B, B) operates
on the word arrays B and B of length B+B and B+B
(B and B are currently allowed to be 0 or negative) and the 2*B
word arrays B and B. B must be a power of 2. It computes
B*B and places the result in B.

bn_mul_part_recursive(B, B, B, B, B, B, B)
operates on the word arrays B and B of length B+B and
B+B and the 4*B word arrays B and B.

bn_mul_low_recursive(B, B, B, B, B) operates on the
B word arrays B and B and the B/2 word arrays B
and B.

BN_mul() calls bn_mul_normal(), or an optimized implementation if the
factors have the same size: bn_mul_comba8() is used if they are 8
words long, bn_mul_recursive() if they are larger than
B and the size is an exact multiple of the word
size, and bn_mul_part_recursive() for others that are larger than
B.

bn_sqr_normal(B, B, B, B) operates on the B word array
B and the 2*B word arrays B and B.

The implementations use the following macros which, depending on the
architecture, may use "long long" C operations or inline assembler.
They are defined in C.

mul(B, B, B, B) computes B*B+B and places the
low word of the result in B and the high word in B.

mul_add(B, B, B, B) computes B*B+B+B and
places the low word of the result in B and the high word in B.

sqr(B, B, B) computes B*B and places the low word
of the result in B and the high word in B.

=head2 Size changes

bn_expand() ensures that B has enough space for a B bit
number. bn_wexpand() ensures that B has enough space for an
B word number. If the number has to be expanded, both macros
call bn_expand2(), which allocates a new B array and copies the
data. They return B on error, B otherwise.

The bn_fix_top() macro reduces Btop> to point to the most
significant non-zero word plus one when B has shrunk.

=head2 Debugging

bn_check_top() verifies that C<((a)-Etop E= 0 && (a)-Etop
E= (a)-Edmax)>. A violation will cause the program to abort.

bn_print() prints B to stderr. bn_dump() prints B words at B
(in reverse order, i.e. most significant word first) to stderr.

bn_set_max() makes B a static number with a B of its current size.
This is used by bn_set_low() and bn_set_high() to make B a read-only
B that contains the B low or high words of B.

If B is not defined, bn_check_top(), bn_print(), bn_dump()
and bn_set_max() are defined as empty macros.

=head1 SEE ALSO

L

=head1 COPYRIGHT

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L.

=cut