1 .\" Automatically generated by Pod::Man version 1.15
2 .\" Tue Jul 30 09:21:27 2002
5 .\" ======================================================================
6 .de Sh \" Subsection heading
14 .de Sp \" Vertical space (when we can't use .PP)
20 .ie \\n(.$>=3 .ne \\$3
24 .de Vb \" Begin verbatim text
29 .de Ve \" End verbatim text
34 .\" Set up some character translations and predefined strings. \*(-- will
35 .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
36 .\" double quote, and \*(R" will give a right double quote. | will give a
37 .\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used
38 .\" to do unbreakable dashes and therefore won't be available. \*(C` and
39 .\" \*(C' expand to `' in nroff, nothing in troff, for use with C<>
41 .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
45 . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
46 . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
59 .\" If the F register is turned on, we'll generate index entries on stderr
60 .\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and
61 .\" index entries marked with X<> in POD. Of course, you'll have to process
62 .\" the output yourself in some meaningful fashion.
65 . tm Index:\\$1\t\\n%\t"\\$2"
71 .\" For nroff, turn off justification. Always turn off hyphenation; it
72 .\" makes way too many mistakes in technical documents.
76 .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
77 .\" Fear. Run. Save yourself. No user-serviceable parts.
79 . \" fudge factors for nroff and troff
88 . ds #H ((1u-(\\\\n(.fu%2u))*.13m)
94 . \" simple accents for nroff and troff
104 . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
105 . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
106 . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
107 . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
108 . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
109 . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
111 . \" troff and (daisy-wheel) nroff accents
112 .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
113 .ds 8 \h'\*(#H'\(*b\h'-\*(#H'
114 .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
115 .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
116 .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
117 .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
118 .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
119 .ds ae a\h'-(\w'a'u*4/10)'e
120 .ds Ae A\h'-(\w'A'u*4/10)'E
121 . \" corrections for vroff
122 .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
123 .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
124 . \" for low resolution devices (crt and lpr)
125 .if \n(.H>23 .if \n(.V>19 \
138 .\" ======================================================================
140 .IX Title "DH_set_method 3"
141 .TH DH_set_method 3 "0.9.6e" "2000-11-12" "OpenSSL"
144 DH_set_default_method, DH_get_default_method, DH_set_method,
145 DH_new_method, DH_OpenSSL \- select \s-1DH\s0 method
147 .IX Header "SYNOPSIS"
149 \& #include <openssl/dh.h>
152 \& void DH_set_default_method(DH_METHOD *meth);
155 \& DH_METHOD *DH_get_default_method(void);
158 \& DH_METHOD *DH_set_method(DH *dh, DH_METHOD *meth);
161 \& DH *DH_new_method(DH_METHOD *meth);
164 \& DH_METHOD *DH_OpenSSL(void);
167 .IX Header "DESCRIPTION"
168 A \fB\s-1DH_METHOD\s0\fR specifies the functions that OpenSSL uses for Diffie-Hellman
169 operations. By modifying the method, alternative implementations
170 such as hardware accelerators may be used.
172 Initially, the default is to use the OpenSSL internal implementation.
173 \&\fIDH_OpenSSL()\fR returns a pointer to that method.
175 \&\fIDH_set_default_method()\fR makes \fBmeth\fR the default method for all \fB\s-1DH\s0\fR
176 structures created later.
178 \&\fIDH_get_default_method()\fR returns a pointer to the current default
181 \&\fIDH_set_method()\fR selects \fBmeth\fR for all operations using the structure \fBdh\fR.
183 \&\fIDH_new_method()\fR allocates and initializes a \fB\s-1DH\s0\fR structure so that
184 \&\fBmethod\fR will be used for the \s-1DH\s0 operations. If \fBmethod\fR is \fB\s-1NULL\s0\fR,
185 the default method is used.
186 .SH "THE DH_METHOD STRUCTURE"
187 .IX Header "THE DH_METHOD STRUCTURE"
189 \& typedef struct dh_meth_st
191 \& /* name of the implementation */
195 \& /* generate private and public DH values for key agreement */
196 \& int (*generate_key)(DH *dh);
199 \& /* compute shared secret */
200 \& int (*compute_key)(unsigned char *key, BIGNUM *pub_key, DH *dh);
203 \& /* compute r = a ^ p mod m (May be NULL for some implementations) */
204 \& int (*bn_mod_exp)(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p,
205 \& const BIGNUM *m, BN_CTX *ctx,
206 \& BN_MONT_CTX *m_ctx);
209 \& /* called at DH_new */
210 \& int (*init)(DH *dh);
213 \& /* called at DH_free */
214 \& int (*finish)(DH *dh);
220 \& char *app_data; /* ?? */
226 .IX Header "RETURN VALUES"
227 \&\fIDH_OpenSSL()\fR and \fIDH_get_default_method()\fR return pointers to the respective
228 \&\fB\s-1DH_METHOD\s0\fRs.
230 \&\fIDH_set_default_method()\fR returns no value.
232 \&\fIDH_set_method()\fR returns a pointer to the \fB\s-1DH_METHOD\s0\fR previously
233 associated with \fBdh\fR.
235 \&\fIDH_new_method()\fR returns \fB\s-1NULL\s0\fR and sets an error code that can be
236 obtained by ERR_get_error(3) if the allocation fails. Otherwise it
237 returns a pointer to the newly allocated structure.
239 .IX Header "SEE ALSO"
243 \&\fIDH_set_default_method()\fR, \fIDH_get_default_method()\fR, \fIDH_set_method()\fR,
244 \&\fIDH_new_method()\fR and \fIDH_OpenSSL()\fR were added in OpenSSL 0.9.4.