NAME
DH_get0_pqg,
DH_set0_pqg, DH_get0_key,
DH_set0_key, DH_clear_flags,
DH_test_flags, DH_set_flags,
DH_get0_engine,
DH_set_length —
get data from and set data in a DH
object
SYNOPSIS
#include
<openssl/dh.h>
void
DH_get0_pqg(const DH *dh,
const BIGNUM **p, const BIGNUM
**q, const BIGNUM **g);
int
DH_set0_pqg(DH *dh,
BIGNUM *p, BIGNUM *q,
BIGNUM *g);
void
DH_get0_key(const DH *dh,
const BIGNUM **pub_key, const BIGNUM
**priv_key);
int
DH_set0_key(DH *dh,
BIGNUM *pub_key, BIGNUM
*priv_key);
void
DH_clear_flags(DH *dh,
int flags);
int
DH_test_flags(const DH *dh,
int flags);
void
DH_set_flags(DH *dh,
int flags);
ENGINE *
DH_get0_engine(DH *d);
int
DH_set_length(DH *dh,
long length);
DESCRIPTION
A DH object contains the parameters p, g, and optionally q. It also contains a public key pub_key and an optional private key priv_key.
The p,
q, and g parameters can be
obtained by calling
DH_get0_pqg().
If the parameters have not yet been set, then *p,
*q, and *g are set to
NULL. Otherwise, they are set to pointers to the
internal representations of the values that should not be freed by the
application. Any of the out parameters p,
q, and g can be
NULL, in which case no value is returned for that
parameter.
The p,
q, and g values can be set by
calling
DH_set0_pqg().
Calling this function transfers the memory management of the values to
dh, and therefore they should not be freed by the
caller. The q argument may be
NULL.
The
DH_get0_key()
function stores pointers to the internal representations of the public key
in *pub_key and to the private key in
*priv_key. Either may be NULL
if it has not yet been set. If the private key has been set, then the public
key must be. Any of the out parameters pub_key and
priv_key can be NULL, in which
case no value is returned for that parameter.
The public and private key values can be set
using
DH_set0_key().
Either parameter may be NULL, which means the
corresponding DH field is left untouched. This
function transfers the memory management of the key values to
dh, and therefore they should not be freed by the
caller.
Values retrieved with
DH_get0_pqg()
and DH_get0_key() are owned by the
DH object and may therefore not be passed to
DH_set0_pqg() or
DH_set0_key(). If needed, duplicate the received
values using BN_dup(3) and pass the duplicates.
DH_clear_flags()
clears the specified flags in
dh.
DH_test_flags()
tests the flags in dh.
DH_set_flags()
sets the flags in dh; any flags
already set remain set. For all three functions, multiple flags can be
passed in one call, OR'ed together bitwise.
DH_set_length()
sets the optional length attribute of dh, indicating
the length of the secret exponent (private key) in bits. If the length
attribute is non-zero, it is used, otherwise it is ignored.
RETURN VALUES
DH_set0_pqg(),
DH_set0_key(), and
DH_set_length() return 1 on success or 0 on
failure.
DH_test_flags() return those of the given
flags currently set in dh or 0
if none of the given flags are set.
DH_get0_engine() returns a pointer to the
ENGINE used by the DH object
dh, or NULL if no engine was
set for this object.
SEE ALSO
DH_generate_key(3), DH_generate_parameters(3), DH_new(3), DH_size(3), DHparams_print(3)
HISTORY
These functions first appeared in OpenSSL 1.1.0 and have been available since OpenBSD 6.3.