22

✏️ Editing: BN_bin2bn.3

.\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35)
.\"
.\" 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_BN2BIN 3"
.TH BN_BN2BIN 3 "2023-09-11" "1.1.1w" "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_bn2binpad, BN_bn2bin, BN_bin2bn, BN_bn2lebinpad, BN_lebin2bn, BN_bn2hex, BN_bn2dec, BN_hex2bn, BN_dec2bn, BN_print, BN_print_fp, BN_bn2mpi, BN_mpi2bn \- format conversions
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/bn.h>
\&
\& int BN_bn2bin(const BIGNUM *a, unsigned char *to);
\& int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen);
\& BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret);
\&
\& int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen);
\& BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret);
\&
\& char *BN_bn2hex(const BIGNUM *a);
\& char *BN_bn2dec(const BIGNUM *a);
\& int BN_hex2bn(BIGNUM **a, const char *str);
\& int BN_dec2bn(BIGNUM **a, const char *str);
\&
\& int BN_print(BIO *fp, const BIGNUM *a);
\& int BN_print_fp(FILE *fp, const BIGNUM *a);
\&
\& int BN_bn2mpi(const BIGNUM *a, unsigned char *to);
\& BIGNUM *BN_mpi2bn(unsigned char *s, int len, BIGNUM *ret);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBBN_bn2bin()\fR converts the absolute value of \fBa\fR into big-endian form
and stores it at \fBto\fR. \fBto\fR must point to BN_num_bytes(\fBa\fR) bytes of
memory.
.PP
\&\fBBN_bn2binpad()\fR also converts the absolute value of \fBa\fR into big-endian form
and stores it at \fBto\fR. \fBtolen\fR indicates the length of the output buffer
\&\fBto\fR. The result is padded with zeros if necessary. If \fBtolen\fR is less than
BN_num_bytes(\fBa\fR) an error is returned.
.PP
\&\fBBN_bin2bn()\fR converts the positive integer in big-endian form of length
\&\fBlen\fR at \fBs\fR into a \fB\s-1BIGNUM\s0\fR and places it in \fBret\fR. If \fBret\fR is
\&\s-1NULL,\s0 a new \fB\s-1BIGNUM\s0\fR is created.
.PP
\&\fBBN_bn2lebinpad()\fR and \fBBN_lebin2bn()\fR are identical to \fBBN_bn2binpad()\fR and
\&\fBBN_bin2bn()\fR except the buffer is in little-endian format.
.PP
\&\fBBN_bn2hex()\fR and \fBBN_bn2dec()\fR return printable strings containing the
hexadecimal and decimal encoding of \fBa\fR respectively. For negative
numbers, the string is prefaced with a leading '\-'. The string must be
freed later using \fBOPENSSL_free()\fR.
.PP
\&\fBBN_hex2bn()\fR takes as many characters as possible from the string \fBstr\fR,
including the leading character '\-' which means negative, to form a valid
hexadecimal number representation and converts them to a \fB\s-1BIGNUM\s0\fR and
stores it in **\fBa\fR. If *\fBa\fR is \s-1NULL,\s0 a new \fB\s-1BIGNUM\s0\fR is created. If
\&\fBa\fR is \s-1NULL,\s0 it only computes the length of valid representation.
A \*(L"negative zero\*(R" is converted to zero.
\&\fBBN_dec2bn()\fR is the same using the decimal system.
.PP
\&\fBBN_print()\fR and \fBBN_print_fp()\fR write the hexadecimal encoding of \fBa\fR,
with a leading '\-' for negative numbers, to the \fB\s-1BIO\s0\fR or \fB\s-1FILE\s0\fR
\&\fBfp\fR.
.PP
\&\fBBN_bn2mpi()\fR and \fBBN_mpi2bn()\fR convert \fB\s-1BIGNUM\s0\fRs from and to a format
that consists of the number's length in bytes represented as a 4\-byte
big-endian number, and the number itself in big-endian format, where
the most significant bit signals a negative number (the representation
of numbers with the \s-1MSB\s0 set is prefixed with null byte).
.PP
\&\fBBN_bn2mpi()\fR stores the representation of \fBa\fR at \fBto\fR, where \fBto\fR
must be large enough to hold the result. The size can be determined by
calling BN_bn2mpi(\fBa\fR, \s-1NULL\s0).
.PP
\&\fBBN_mpi2bn()\fR converts the \fBlen\fR bytes long representation at \fBs\fR to
a \fB\s-1BIGNUM\s0\fR and stores it at \fBret\fR, or in a newly allocated \fB\s-1BIGNUM\s0\fR
if \fBret\fR is \s-1NULL.\s0
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBBN_bn2bin()\fR returns the length of the big-endian number placed at \fBto\fR.
\&\fBBN_bin2bn()\fR returns the \fB\s-1BIGNUM\s0\fR, \s-1NULL\s0 on error.
.PP
\&\fBBN_bn2binpad()\fR returns the number of bytes written or \-1 if the supplied
buffer is too small.
.PP
\&\fBBN_bn2hex()\fR and \fBBN_bn2dec()\fR return a null-terminated string, or \s-1NULL\s0
on error. \fBBN_hex2bn()\fR and \fBBN_dec2bn()\fR return the number of characters
used in parsing, or 0 on error, in which
case no new \fB\s-1BIGNUM\s0\fR will be created.
.PP
\&\fBBN_print_fp()\fR and \fBBN_print()\fR return 1 on success, 0 on write errors.
.PP
\&\fBBN_bn2mpi()\fR returns the length of the representation. \fBBN_mpi2bn()\fR
returns the \fB\s-1BIGNUM\s0\fR, and \s-1NULL\s0 on error.
.PP
The error codes can be obtained by \fBERR_get_error\fR\|(3).
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBERR_get_error\fR\|(3), \fBBN_zero\fR\|(3),
\&\fBASN1_INTEGER_to_BN\fR\|(3),
\&\fBBN_num_bytes\fR\|(3)
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2000\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (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>.

MR SKB