1 .\" Automatically generated by Pod::Man version 1.15
2 .\" Thu May 9 13:16:37 2002
5 .\" ======================================================================
6 .de Sh \" Subsection heading
14 .de Sp \" Vertical space (when we can't use .PP)
20 .ie \\n(.$>=3 .ne \\$3
24 .de Vb \" Begin verbatim text
29 .de Ve \" End verbatim text
34 .\" Set up some character translations and predefined strings. \*(-- will
35 .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
36 .\" double quote, and \*(R" will give a right double quote. | will give a
37 .\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used
38 .\" to do unbreakable dashes and therefore won't be available. \*(C` and
39 .\" \*(C' expand to `' in nroff, nothing in troff, for use with C<>
41 .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
45 . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
46 . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
59 .\" If the F register is turned on, we'll generate index entries on stderr
60 .\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and
61 .\" index entries marked with X<> in POD. Of course, you'll have to process
62 .\" the output yourself in some meaningful fashion.
65 . tm Index:\\$1\t\\n%\t"\\$2"
71 .\" For nroff, turn off justification. Always turn off hyphenation; it
72 .\" makes way too many mistakes in technical documents.
76 .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
77 .\" Fear. Run. Save yourself. No user-serviceable parts.
79 . \" fudge factors for nroff and troff
88 . ds #H ((1u-(\\\\n(.fu%2u))*.13m)
94 . \" simple accents for nroff and troff
104 . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
105 . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
106 . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
107 . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
108 . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
109 . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
111 . \" troff and (daisy-wheel) nroff accents
112 .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
113 .ds 8 \h'\*(#H'\(*b\h'-\*(#H'
114 .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
115 .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
116 .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
117 .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
118 .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
119 .ds ae a\h'-(\w'a'u*4/10)'e
120 .ds Ae A\h'-(\w'A'u*4/10)'E
121 . \" corrections for vroff
122 .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
123 .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
124 . \" for low resolution devices (crt and lpr)
125 .if \n(.H>23 .if \n(.V>19 \
138 .\" ======================================================================
140 .IX Title "BN_MOD_MUL_RECIPROCAL 1"
141 .TH BN_MOD_MUL_RECIPROCAL 1 "perl v5.6.1" "2000-11-13" "User Contributed Perl Documentation"
144 BN_mod_mul_reciprocal, BN_div_recp, BN_RECP_CTX_new, BN_RECP_CTX_init,
145 BN_RECP_CTX_free, BN_RECP_CTX_set \- modular multiplication using
148 .IX Header "SYNOPSIS"
150 \& #include <openssl/bn.h>
153 \& BN_RECP_CTX *BN_RECP_CTX_new(void);
154 \& void BN_RECP_CTX_init(BN_RECP_CTX *recp);
155 \& void BN_RECP_CTX_free(BN_RECP_CTX *recp);
158 \& int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *m, BN_CTX *ctx);
161 \& int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *a, BN_RECP_CTX *recp,
165 \& int BN_mod_mul_reciprocal(BIGNUM *r, BIGNUM *a, BIGNUM *b,
166 \& BN_RECP_CTX *recp, BN_CTX *ctx);
169 .IX Header "DESCRIPTION"
170 \&\fIBN_mod_mul_reciprocal()\fR can be used to perform an efficient
171 BN_mod_mul(3) operation when the operation will be performed
172 repeatedly with the same modulus. It computes \fBr\fR=(\fBa\fR*\fBb\fR)%\fBm\fR
173 using \fBrecp\fR=1/\fBm\fR, which is set as described below. \fBctx\fR is a
174 previously allocated \fB\s-1BN_CTX\s0\fR used for temporary variables.
176 \&\fIBN_RECP_CTX_new()\fR allocates and initializes a \fB\s-1BN_RECP\s0\fR structure.
177 \&\fIBN_RECP_CTX_init()\fR initializes an existing uninitialized \fB\s-1BN_RECP\s0\fR.
179 \&\fIBN_RECP_CTX_free()\fR frees the components of the \fB\s-1BN_RECP\s0\fR, and, if it
180 was created by \fIBN_RECP_CTX_new()\fR, also the structure itself.
182 \&\fIBN_RECP_CTX_set()\fR stores \fBm\fR in \fBrecp\fR and sets it up for computing
183 1/\fBm\fR and shifting it left by BN_num_bits(\fBm\fR)+1 to make it an
184 integer. The result and the number of bits it was shifted left will
185 later be stored in \fBrecp\fR.
187 \&\fIBN_div_recp()\fR divides \fBa\fR by \fBm\fR using \fBrecp\fR. It places the quotient
188 in \fBdv\fR and the remainder in \fBrem\fR.
190 The \fB\s-1BN_RECP_CTX\s0\fR structure is defined as follows:
193 \& typedef struct bn_recp_ctx_st
195 \& BIGNUM N; /* the divisor */
196 \& BIGNUM Nr; /* the reciprocal */
202 It cannot be shared between threads.
204 .IX Header "RETURN VALUES"
205 \&\fIBN_RECP_CTX_new()\fR returns the newly allocated \fB\s-1BN_RECP_CTX\s0\fR, and \s-1NULL\s0
208 \&\fIBN_RECP_CTX_init()\fR and \fIBN_RECP_CTX_free()\fR have no return values.
210 For the other functions, 1 is returned for success, 0 on error.
211 The error codes can be obtained by ERR_get_error(3).
213 .IX Header "SEE ALSO"
214 bn(3), err(3), BN_add(3),
218 \&\fB\s-1BN_RECP_CTX\s0\fR was added in SSLeay 0.9.0. Before that, the function
219 \&\fIBN_reciprocal()\fR was used instead, and the \fIBN_mod_mul_reciprocal()\fR
220 arguments were different.