.\" Automatically generated by Pod::Man 4.14 (Pod::Simple 3.42)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
.    ds C`
.    ds C'
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is >0, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.\"
.\" Avoid warning from groff about undefined register 'F'.
.de IX
..
.nr rF 0
.if \n(.g .if rF .nr rF 1
.if (\n(rF:(\n(.g==0)) \{\
.    if \nF \{\
.        de IX
.        tm Index:\\$1\t\\n%\t"\\$2"
..
.        if !\nF==2 \{\
.            nr % 0
.            nr F 2
.        \}
.    \}
.\}
.rr rF
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "BN_BLINDING_NEW 3ossl"
.TH BN_BLINDING_NEW 3ossl "2026-01-27" "3.5.5" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
BN_BLINDING_new, BN_BLINDING_free, BN_BLINDING_update, BN_BLINDING_convert,
BN_BLINDING_invert, BN_BLINDING_convert_ex, BN_BLINDING_invert_ex,
BN_BLINDING_is_current_thread, BN_BLINDING_set_current_thread,
BN_BLINDING_lock, BN_BLINDING_unlock, BN_BLINDING_get_flags,
BN_BLINDING_set_flags, BN_BLINDING_create_param \- blinding related BIGNUM functions
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/bn.h>
\&
\& BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai,
\&                              BIGNUM *mod);
\& void BN_BLINDING_free(BN_BLINDING *b);
\& int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx);
\& int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx);
\& int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx);
\& int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b,
\&                            BN_CTX *ctx);
\& int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b,
\&                           BN_CTX *ctx);
\& int BN_BLINDING_is_current_thread(BN_BLINDING *b);
\& void BN_BLINDING_set_current_thread(BN_BLINDING *b);
\& int BN_BLINDING_lock(BN_BLINDING *b);
\& int BN_BLINDING_unlock(BN_BLINDING *b);
\& unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b);
\& void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags);
\& BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
\&                                       const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
\&                                       int (*bn_mod_exp)(BIGNUM *r,
\&                                                         const BIGNUM *a,
\&                                                         const BIGNUM *p,
\&                                                         const BIGNUM *m,
\&                                                         BN_CTX *ctx,
\&                                                         BN_MONT_CTX *m_ctx),
\&                                       BN_MONT_CTX *m_ctx);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBBN_BLINDING_new()\fR allocates a new \fB\s-1BN_BLINDING\s0\fR structure and copies
the \fBA\fR and \fBAi\fR values into the newly created \fB\s-1BN_BLINDING\s0\fR object.
.PP
\&\fBBN_BLINDING_free()\fR frees the \fB\s-1BN_BLINDING\s0\fR structure.
If \fBb\fR is \s-1NULL,\s0 nothing is done.
.PP
\&\fBBN_BLINDING_update()\fR updates the \fB\s-1BN_BLINDING\s0\fR parameters by squaring
the \fBA\fR and \fBAi\fR or, after specific number of uses and if the
necessary parameters are set, by re-creating the blinding parameters.
.PP
\&\fBBN_BLINDING_convert_ex()\fR multiplies \fBn\fR with the blinding factor \fBA\fR.
If \fBr\fR is not \s-1NULL\s0 a copy the inverse blinding factor \fBAi\fR will be
returned in \fBr\fR (this is useful if a \fB\s-1RSA\s0\fR object is shared among
several threads). \fBBN_BLINDING_invert_ex()\fR multiplies \fBn\fR with the
inverse blinding factor \fBAi\fR. If \fBr\fR is not \s-1NULL\s0 it will be used as
the inverse blinding.
.PP
\&\fBBN_BLINDING_convert()\fR and \fBBN_BLINDING_invert()\fR are wrapper
functions for \fBBN_BLINDING_convert_ex()\fR and \fBBN_BLINDING_invert_ex()\fR
with \fBr\fR set to \s-1NULL.\s0
.PP
\&\fBBN_BLINDING_is_current_thread()\fR returns whether the \fB\s-1BN_BLINDING\s0\fR
structure is owned by the current thread. This is to help users
provide proper locking if needed for multi-threaded use.
.PP
\&\fBBN_BLINDING_set_current_thread()\fR sets the current thread as the
owner of the \fB\s-1BN_BLINDING\s0\fR structure.
.PP
\&\fBBN_BLINDING_lock()\fR locks the \fB\s-1BN_BLINDING\s0\fR structure.
.PP
\&\fBBN_BLINDING_unlock()\fR unlocks the \fB\s-1BN_BLINDING\s0\fR structure.
.PP
\&\fBBN_BLINDING_get_flags()\fR returns the \s-1BN_BLINDING\s0 flags. Currently
there are two supported flags: \fB\s-1BN_BLINDING_NO_UPDATE\s0\fR and
\&\fB\s-1BN_BLINDING_NO_RECREATE\s0\fR. \fB\s-1BN_BLINDING_NO_UPDATE\s0\fR inhibits the
automatic update of the \fB\s-1BN_BLINDING\s0\fR parameters after each use
and \fB\s-1BN_BLINDING_NO_RECREATE\s0\fR inhibits the automatic re-creation
of the \fB\s-1BN_BLINDING\s0\fR parameters after a fixed number of uses (currently
32). In newly allocated \fB\s-1BN_BLINDING\s0\fR objects no flags are set.
\&\fBBN_BLINDING_set_flags()\fR sets the \fB\s-1BN_BLINDING\s0\fR parameters flags.
.PP
\&\fBBN_BLINDING_create_param()\fR creates new \fB\s-1BN_BLINDING\s0\fR parameters
using the exponent \fBe\fR and the modulus \fBm\fR. \fBbn_mod_exp\fR and
\&\fBm_ctx\fR can be used to pass special functions for exponentiation
(normally \fBBN_mod_exp_mont()\fR and \fB\s-1BN_MONT_CTX\s0\fR).
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBBN_BLINDING_new()\fR returns the newly allocated \fB\s-1BN_BLINDING\s0\fR structure
or \s-1NULL\s0 in case of an error.
.PP
\&\fBBN_BLINDING_update()\fR, \fBBN_BLINDING_convert()\fR, \fBBN_BLINDING_invert()\fR,
\&\fBBN_BLINDING_convert_ex()\fR and \fBBN_BLINDING_invert_ex()\fR return 1 on
success and 0 if an error occurred.
.PP
\&\fBBN_BLINDING_is_current_thread()\fR returns 1 if the current thread owns
the \fB\s-1BN_BLINDING\s0\fR object, 0 otherwise.
.PP
\&\fBBN_BLINDING_set_current_thread()\fR doesn't return anything.
.PP
\&\fBBN_BLINDING_lock()\fR, \fBBN_BLINDING_unlock()\fR return 1 if the operation
succeeded or 0 on error.
.PP
\&\fBBN_BLINDING_get_flags()\fR returns the currently set \fB\s-1BN_BLINDING\s0\fR flags
(a \fBunsigned long\fR value).
.PP
\&\fBBN_BLINDING_create_param()\fR returns the newly created \fB\s-1BN_BLINDING\s0\fR
parameters or \s-1NULL\s0 on error.
.SH "HISTORY"
.IX Header "HISTORY"
\&\fBBN_BLINDING_thread_id()\fR was first introduced in OpenSSL 1.0.0, and it
deprecates \fBBN_BLINDING_set_thread_id()\fR and \fBBN_BLINDING_get_thread_id()\fR.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2005\-2017 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the Apache License 2.0 (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.
