.\" $OpenBSD: DH_get0_pqg.3,v 1.7 2023/03/06 13:25:46 tb Exp $ .\" selective merge up to: OpenSSL 83cf7abf May 29 13:07:08 2018 +0100 .\" .\" This file was written by Matt Caswell . .\" Copyright (c) 2016, 2018 The OpenSSL Project. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in .\" the documentation and/or other materials provided with the .\" distribution. .\" .\" 3. 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IN NO EVENT SHALL THE OpenSSL PROJECT OR .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED .\" OF THE POSSIBILITY OF SUCH DAMAGE. .\" .Dd $Mdocdate: March 6 2023 $ .Dt DH_GET0_PQG 3 .Os .Sh NAME .Nm DH_get0_pqg , .Nm DH_get0_p , .Nm DH_get0_q , .Nm DH_get0_g , .Nm DH_set0_pqg , .Nm DH_get0_key , .Nm DH_get0_pub_key , .Nm DH_get0_priv_key , .Nm DH_set0_key , .Nm DH_clear_flags , .Nm DH_test_flags , .Nm DH_set_flags , .Nm DH_get0_engine , .Nm DH_set_length .Nd get data from and set data in a DH object .Sh SYNOPSIS .In openssl/dh.h .Ft void .Fo DH_get0_pqg .Fa "const DH *dh" .Fa "const BIGNUM **p" .Fa "const BIGNUM **q" .Fa "const BIGNUM **g" .Fc .Ft "const BIGNUM *" .Fo DH_get0_p .Fa "const DH *dh" .Fc .Ft "const BIGNUM *" .Fo DH_get0_q .Fa "const DH *dh" .Fc .Ft "const BIGNUM *" .Fo DH_get0_g .Fa "const DH *dh" .Fc .Ft int .Fo DH_set0_pqg .Fa "DH *dh" .Fa "BIGNUM *p" .Fa "BIGNUM *q" .Fa "BIGNUM *g" .Fc .Ft void .Fo DH_get0_key .Fa "const DH *dh" .Fa "const BIGNUM **pub_key" .Fa "const BIGNUM **priv_key" .Fc .Ft "const BIGNUM *" .Fo DH_get0_pub_key .Fa "const DH *dh" .Fc .Ft "const BIGNUM *" .Fo DH_get0_priv_key .Fa "const DH *dh" .Fc .Ft int .Fo DH_set0_key .Fa "DH *dh" .Fa "BIGNUM *pub_key" .Fa "BIGNUM *priv_key" .Fc .Ft void .Fo DH_clear_flags .Fa "DH *dh" .Fa "int flags" .Fc .Ft int .Fo DH_test_flags .Fa "const DH *dh" .Fa "int flags" .Fc .Ft void .Fo DH_set_flags .Fa "DH *dh" .Fa "int flags" .Fc .Ft ENGINE * .Fo DH_get0_engine .Fa "DH *d" .Fc .Ft int .Fo DH_set_length .Fa "DH *dh" .Fa "long length" .Fc .Sh DESCRIPTION A .Vt DH object contains the parameters .Fa p , .Fa g , and optionally .Fa q . It also contains a public key .Fa pub_key and an optional private key .Fa priv_key . .Pp The .Fa p , .Fa q , and .Fa g parameters can be obtained by calling .Fn DH_get0_pqg . If the parameters have not yet been set, then .Pf * Fa p , .Pf * Fa q , and .Pf * Fa g are set to .Dv 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 .Fa p , .Fa q , and .Fa g can be .Dv NULL , in which case no value is returned for that parameter. .Pp The .Fa p , .Fa q , and .Fa g values can be set by calling .Fn DH_set0_pqg . Calling this function transfers the memory management of the values to .Fa dh , and therefore they should not be freed by the caller. The .Fa q argument may be .Dv NULL . .Pp The .Fn DH_get0_key function stores pointers to the internal representations of the public key in .Pf * Fa pub_key and to the private key in .Pf * Fa priv_key . Either may be .Dv 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 .Fa pub_key and .Fa priv_key can be .Dv NULL , in which case no value is returned for that parameter. .Pp The public and private key values can be set using .Fn DH_set0_key . Either parameter may be .Dv NULL , which means the corresponding .Vt DH field is left untouched. This function transfers the memory management of the key values to .Fa dh , and therefore they should not be freed by the caller. .Pp Values retrieved with .Fn DH_get0_pqg and .Fn DH_get0_key are owned by the .Vt DH object and may therefore not be passed to .Fn DH_set0_pqg or .Fn DH_set0_key . If needed, duplicate the received values using .Xr BN_dup 3 and pass the duplicates. .Pp Any of the values .Fa p , .Fa q , .Fa g , .Fa pub_key , and .Fa priv_key can also be retrieved separately by the corresponding functions .Fn DH_get0_p , .Fn DH_get0_q , .Fn DH_get0_g , .Fn DH_get0_pub_key , and .Fn DH_get0_priv_key , respectively. The pointers are owned by the .Vt DH object. .Pp .Fn DH_clear_flags clears the specified .Fa flags in .Fa dh . .Fn DH_test_flags tests the .Fa flags in .Fa dh . .Fn DH_set_flags sets the .Fa flags in .Fa dh ; any flags already set remain set. For all three functions, multiple flags can be passed in one call, OR'ed together bitwise. .Pp .Fn DH_set_length sets the optional length attribute of .Fa 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. .Sh RETURN VALUES +.Fn DH_get0_p , +.Fn DH_get0_q , +.Fn DH_get0_g , +.Fn DH_get0_pub_key , +and +.Fn DH_get0_priv_key , +return a pointer owned by the +.Vt DH +object if the corresponding value has been set, +otherwise they return +.Dv NULL . .Fn DH_set0_pqg , .Fn DH_set0_key , and .Fn DH_set_length return 1 on success or 0 on failure. .Pp .Fn DH_test_flags return those of the given .Fa flags currently set in .Fa dh or 0 if none of the given .Fa flags are set. .Pp .Fn DH_get0_engine returns a pointer to the .Vt ENGINE used by the .Vt DH object .Fa dh , or .Dv NULL if no engine was set for this object. .Sh SEE ALSO .Xr DH_generate_key 3 , .Xr DH_generate_parameters 3 , .Xr DH_new 3 , .Xr DH_security_bits 3 , .Xr DH_size 3 , .Xr DHparams_print 3 .Sh HISTORY .Fn DH_get0_pqg , .Fn DH_set0_pqg , .Fn DH_get0_key , .Fn DH_set0_key , .Fn DH_clear_flags , .Fn DH_test_flags , .Fn DH_set_flags , .Fn DH_get0_engine , and .Fn DH_set_length first appeared in OpenSSL 1.1.0 and have been available since .Ox 6.3 . .Pp .Fn DH_get0_p , .Fn DH_get0_q , .Fn DH_get0_g , .Fn DH_get0_pub_key , and .Fn DH_get0_priv_key first appeared in OpenSSL 1.1.1 and have been available since .Ox 7.1 .