flutter / third_party / openssl / 4b1b629725970384d6cf4dafe9e83e54859574cd / . / doc / man3 / BN_bn2bin.pod

=pod | |

=head1 NAME | |

BN_bn2binpad, BN_signed_bn2bin, BN_bn2bin, BN_bin2bn, BN_signed_bin2bn, | |

BN_bn2lebinpad, BN_signed_bn2lebin, BN_lebin2bn, BN_signed_lebin2bn, | |

BN_bn2nativepad, BN_signed_bn2native, BN_native2bn, BN_signed_native2bn, | |

BN_bn2hex, BN_bn2dec, BN_hex2bn, BN_dec2bn, | |

BN_print, BN_print_fp, BN_bn2mpi, BN_mpi2bn - format conversions | |

=head1 SYNOPSIS | |

#include <openssl/bn.h> | |

int BN_bn2bin(const BIGNUM *a, unsigned char *to); | |

int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen); | |

int BN_signed_bn2bin(const BIGNUM *a, unsigned char *to, int tolen); | |

BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret); | |

BIGNUM *BN_signed_bin2bn(const unsigned char *s, int len, BIGNUM *ret); | |

int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen); | |

int BN_signed_bn2lebin(const BIGNUM *a, unsigned char *to, int tolen); | |

BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret); | |

BIGNUM *BN_signed_lebin2bn(const unsigned char *s, int len, BIGNUM *ret); | |

int BN_bn2nativepad(const BIGNUM *a, unsigned char *to, int tolen); | |

int BN_signed_bn2native(const BIGNUM *a, unsigned char *to, int tolen); | |

BIGNUM *BN_native2bn(const unsigned char *s, int len, BIGNUM *ret); | |

BIGNUM *BN_signed_native2bn(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); | |

=head1 DESCRIPTION | |

BN_bn2bin() converts the absolute value of B<a> into big-endian form | |

and stores it at B<to>. B<to> must point to BN_num_bytes(B<a>) bytes of | |

memory. | |

BN_bn2binpad() also converts the absolute value of B<a> into big-endian form | |

and stores it at B<to>. B<tolen> indicates the length of the output buffer | |

B<to>. The result is padded with zeros if necessary. If B<tolen> is less than | |

BN_num_bytes(B<a>) an error is returned. | |

BN_signed_bn2bin() converts the value of B<a> into big-endian signed 2's | |

complements form and stores it at B<to>. B<tolen> indicates the length of | |

the output buffer B<to>. The result is signed extended (padded with 0x00 | |

for positive numbers or with 0xff for negative numbers) if necessary. | |

If B<tolen> is smaller than the necessary size (which may be | |

C<<BN_num_bytes(B<a>) + 1>>), an error is returned. | |

BN_bin2bn() converts the positive integer in big-endian form of length | |

B<len> at B<s> into a B<BIGNUM> and places it in B<ret>. If B<ret> is | |

NULL, a new B<BIGNUM> is created. | |

BN_signed_bin2bn() converts the integer in big-endian signed 2's complement | |

form of length B<len> at B<s> into a B<BIGNUM> and places it in B<ret>. If | |

B<ret> is NULL, a new B<BIGNUM> is created. | |

BN_bn2lebinpad(), BN_signed_bn2lebin() and BN_lebin2bn() are identical to | |

BN_bn2binpad(), BN_signed_bn2bin() and BN_bin2bn() except the buffer is in | |

little-endian format. | |

BN_bn2nativepad(), BN_signed_bn2native() and BN_native2bn() are identical | |

to BN_bn2binpad(), BN_signed_bn2bin() and BN_bin2bn() except the buffer is | |

in native format, i.e. most significant byte first on big-endian platforms, | |

and least significant byte first on little-endian platforms. | |

BN_bn2hex() and BN_bn2dec() return printable strings containing the | |

hexadecimal and decimal encoding of B<a> respectively. For negative | |

numbers, the string is prefaced with a leading '-'. The string must be | |

freed later using OPENSSL_free(). | |

BN_hex2bn() takes as many characters as possible from the string B<str>, | |

including the leading character '-' which means negative, to form a valid | |

hexadecimal number representation and converts them to a B<BIGNUM> and | |

stores it in **B<a>. If *B<a> is NULL, a new B<BIGNUM> is created. If | |

B<a> is NULL, it only computes the length of valid representation. | |

A "negative zero" is converted to zero. | |

BN_dec2bn() is the same using the decimal system. | |

BN_print() and BN_print_fp() write the hexadecimal encoding of B<a>, | |

with a leading '-' for negative numbers, to the B<BIO> or B<FILE> | |

B<fp>. | |

BN_bn2mpi() and BN_mpi2bn() convert B<BIGNUM>s 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 MSB set is prefixed with null byte). | |

BN_bn2mpi() stores the representation of B<a> at B<to>, where B<to> | |

must be large enough to hold the result. The size can be determined by | |

calling BN_bn2mpi(B<a>, NULL). | |

BN_mpi2bn() converts the B<len> bytes long representation at B<s> to | |

a B<BIGNUM> and stores it at B<ret>, or in a newly allocated B<BIGNUM> | |

if B<ret> is NULL. | |

=head1 RETURN VALUES | |

BN_bn2bin() returns the length of the big-endian number placed at B<to>. | |

BN_bin2bn() returns the B<BIGNUM>, NULL on error. | |

BN_bn2binpad(), BN_signed_bn2bin(), BN_bn2lebinpad(), BN_signed_bn2lebin(), | |

BN_bn2nativepad(), and_signed BN_bn2native() return the number of bytes | |

written or -1 if the supplied buffer is too small. | |

BN_bn2hex() and BN_bn2dec() return a NUL-terminated string, or NULL | |

on error. BN_hex2bn() and BN_dec2bn() return the number of characters | |

used in parsing, or 0 on error, in which | |

case no new B<BIGNUM> will be created. | |

BN_print_fp() and BN_print() return 1 on success, 0 on write errors. | |

BN_bn2mpi() returns the length of the representation. BN_mpi2bn() | |

returns the B<BIGNUM>, and NULL on error. | |

The error codes can be obtained by L<ERR_get_error(3)>. | |

=head1 SEE ALSO | |

L<ERR_get_error(3)>, L<BN_zero(3)>, | |

L<ASN1_INTEGER_to_BN(3)>, | |

L<BN_num_bytes(3)> | |

=head1 COPYRIGHT | |

Copyright 2000-2022 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<https://www.openssl.org/source/license.html>. | |

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