summaryrefslogtreecommitdiffstats
path: root/secure/lib/libcrypto/man/RSA_set_method.3
blob: 1f9c8718e5ce98f3e8ab20407797cb3a130be834 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.32
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sh \" Subsection heading
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.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.  | will give a
.\" real vertical bar.  \*(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-|\(bv\*(Tr
.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" ''
'br\}
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.if \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
..
.    nr % 0
.    rr F
.\}
.\"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.hy 0
.if n .na
.\"
.\" 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 "RSA_set_method 3"
.TH RSA_set_method 3 "2006-10-01" "0.9.8d" "OpenSSL"
.SH "NAME"
RSA_set_default_method, RSA_get_default_method, RSA_set_method,
RSA_get_method, RSA_PKCS1_SSLeay, RSA_null_method, RSA_flags,
RSA_new_method \- select RSA method
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/rsa.h>
.Ve
.PP
.Vb 1
\& void RSA_set_default_method(const RSA_METHOD *meth);
.Ve
.PP
.Vb 1
\& RSA_METHOD *RSA_get_default_method(void);
.Ve
.PP
.Vb 1
\& int RSA_set_method(RSA *rsa, const RSA_METHOD *meth);
.Ve
.PP
.Vb 1
\& RSA_METHOD *RSA_get_method(const RSA *rsa);
.Ve
.PP
.Vb 1
\& RSA_METHOD *RSA_PKCS1_SSLeay(void);
.Ve
.PP
.Vb 1
\& RSA_METHOD *RSA_null_method(void);
.Ve
.PP
.Vb 1
\& int RSA_flags(const RSA *rsa);
.Ve
.PP
.Vb 1
\& RSA *RSA_new_method(RSA_METHOD *method);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
An \fB\s-1RSA_METHOD\s0\fR specifies the functions that OpenSSL uses for \s-1RSA\s0
operations. By modifying the method, alternative implementations such as
hardware accelerators may be used. \s-1IMPORTANT:\s0 See the \s-1NOTES\s0 section for
important information about how these \s-1RSA\s0 \s-1API\s0 functions are affected by the
use of \fB\s-1ENGINE\s0\fR \s-1API\s0 calls.
.PP
Initially, the default \s-1RSA_METHOD\s0 is the OpenSSL internal implementation,
as returned by \fIRSA_PKCS1_SSLeay()\fR.
.PP
\&\fIRSA_set_default_method()\fR makes \fBmeth\fR the default method for all \s-1RSA\s0
structures created later. \fB\s-1NB\s0\fR: This is true only whilst no \s-1ENGINE\s0 has
been set as a default for \s-1RSA\s0, so this function is no longer recommended.
.PP
\&\fIRSA_get_default_method()\fR returns a pointer to the current default
\&\s-1RSA_METHOD\s0. However, the meaningfulness of this result is dependant on
whether the \s-1ENGINE\s0 \s-1API\s0 is being used, so this function is no longer 
recommended.
.PP
\&\fIRSA_set_method()\fR selects \fBmeth\fR to perform all operations using the key
\&\fBrsa\fR. This will replace the \s-1RSA_METHOD\s0 used by the \s-1RSA\s0 key and if the
previous method was supplied by an \s-1ENGINE\s0, the handle to that \s-1ENGINE\s0 will
be released during the change. It is possible to have \s-1RSA\s0 keys that only
work with certain \s-1RSA_METHOD\s0 implementations (eg. from an \s-1ENGINE\s0 module
that supports embedded hardware-protected keys), and in such cases
attempting to change the \s-1RSA_METHOD\s0 for the key can have unexpected
results.
.PP
\&\fIRSA_get_method()\fR returns a pointer to the \s-1RSA_METHOD\s0 being used by \fBrsa\fR.
This method may or may not be supplied by an \s-1ENGINE\s0 implementation, but if
it is, the return value can only be guaranteed to be valid as long as the
\&\s-1RSA\s0 key itself is valid and does not have its implementation changed by
\&\fIRSA_set_method()\fR.
.PP
\&\fIRSA_flags()\fR returns the \fBflags\fR that are set for \fBrsa\fR's current
\&\s-1RSA_METHOD\s0. See the \s-1BUGS\s0 section.
.PP
\&\fIRSA_new_method()\fR allocates and initializes an \s-1RSA\s0 structure so that
\&\fBengine\fR will be used for the \s-1RSA\s0 operations. If \fBengine\fR is \s-1NULL\s0, the
default \s-1ENGINE\s0 for \s-1RSA\s0 operations is used, and if no default \s-1ENGINE\s0 is set,
the \s-1RSA_METHOD\s0 controlled by \fIRSA_set_default_method()\fR is used.
.PP
\&\fIRSA_flags()\fR returns the \fBflags\fR that are set for \fBrsa\fR's current method.
.PP
\&\fIRSA_new_method()\fR allocates and initializes an \fB\s-1RSA\s0\fR structure so that
\&\fBmethod\fR will be used for the \s-1RSA\s0 operations. If \fBmethod\fR is \fB\s-1NULL\s0\fR,
the default method is used.
.SH "THE RSA_METHOD STRUCTURE"
.IX Header "THE RSA_METHOD STRUCTURE"
.Vb 4
\& typedef struct rsa_meth_st
\& {
\&     /* name of the implementation */
\&        const char *name;
.Ve
.PP
.Vb 3
\&     /* encrypt */
\&        int (*rsa_pub_enc)(int flen, unsigned char *from,
\&          unsigned char *to, RSA *rsa, int padding);
.Ve
.PP
.Vb 3
\&     /* verify arbitrary data */
\&        int (*rsa_pub_dec)(int flen, unsigned char *from,
\&          unsigned char *to, RSA *rsa, int padding);
.Ve
.PP
.Vb 3
\&     /* sign arbitrary data */
\&        int (*rsa_priv_enc)(int flen, unsigned char *from,
\&          unsigned char *to, RSA *rsa, int padding);
.Ve
.PP
.Vb 3
\&     /* decrypt */
\&        int (*rsa_priv_dec)(int flen, unsigned char *from,
\&          unsigned char *to, RSA *rsa, int padding);
.Ve
.PP
.Vb 3
\&     /* compute r0 = r0 ^ I mod rsa->n (May be NULL for some
\&                                        implementations) */
\&        int (*rsa_mod_exp)(BIGNUM *r0, BIGNUM *I, RSA *rsa);
.Ve
.PP
.Vb 3
\&     /* compute r = a ^ p mod m (May be NULL for some implementations) */
\&        int (*bn_mod_exp)(BIGNUM *r, BIGNUM *a, const BIGNUM *p,
\&          const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
.Ve
.PP
.Vb 2
\&     /* called at RSA_new */
\&        int (*init)(RSA *rsa);
.Ve
.PP
.Vb 2
\&     /* called at RSA_free */
\&        int (*finish)(RSA *rsa);
.Ve
.PP
.Vb 7
\&     /* RSA_FLAG_EXT_PKEY        - rsa_mod_exp is called for private key
\&      *                            operations, even if p,q,dmp1,dmq1,iqmp
\&      *                            are NULL
\&      * RSA_FLAG_SIGN_VER        - enable rsa_sign and rsa_verify
\&      * RSA_METHOD_FLAG_NO_CHECK - don't check pub/private match
\&      */
\&        int flags;
.Ve
.PP
.Vb 1
\&        char *app_data; /* ?? */
.Ve
.PP
.Vb 5
\&     /* sign. For backward compatibility, this is used only
\&      * if (flags & RSA_FLAG_SIGN_VER)
\&      */
\&        int (*rsa_sign)(int type, unsigned char *m, unsigned int m_len,
\&           unsigned char *sigret, unsigned int *siglen, RSA *rsa);
.Ve
.PP
.Vb 5
\&     /* verify. For backward compatibility, this is used only
\&      * if (flags & RSA_FLAG_SIGN_VER)
\&      */
\&        int (*rsa_verify)(int type, unsigned char *m, unsigned int m_len,
\&           unsigned char *sigbuf, unsigned int siglen, RSA *rsa);
.Ve
.PP
.Vb 1
\& } RSA_METHOD;
.Ve
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fIRSA_PKCS1_SSLeay()\fR, \fIRSA_PKCS1_null_method()\fR, \fIRSA_get_default_method()\fR
and \fIRSA_get_method()\fR return pointers to the respective RSA_METHODs.
.PP
\&\fIRSA_set_default_method()\fR returns no value.
.PP
\&\fIRSA_set_method()\fR returns a pointer to the old \s-1RSA_METHOD\s0 implementation
that was replaced. However, this return value should probably be ignored
because if it was supplied by an \s-1ENGINE\s0, the pointer could be invalidated
at any time if the \s-1ENGINE\s0 is unloaded (in fact it could be unloaded as a
result of the \fIRSA_set_method()\fR function releasing its handle to the
\&\s-1ENGINE\s0). For this reason, the return type may be replaced with a \fBvoid\fR
declaration in a future release.
.PP
\&\fIRSA_new_method()\fR returns \s-1NULL\s0 and sets an error code that can be obtained
by \fIERR_get_error\fR\|(3) if the allocation fails. Otherwise
it returns a pointer to the newly allocated structure.
.SH "NOTES"
.IX Header "NOTES"
As of version 0.9.7, \s-1RSA_METHOD\s0 implementations are grouped together with
other algorithmic APIs (eg. \s-1DSA_METHOD\s0, \s-1EVP_CIPHER\s0, etc) into \fB\s-1ENGINE\s0\fR
modules. If a default \s-1ENGINE\s0 is specified for \s-1RSA\s0 functionality using an
\&\s-1ENGINE\s0 \s-1API\s0 function, that will override any \s-1RSA\s0 defaults set using the \s-1RSA\s0
\&\s-1API\s0 (ie.  \fIRSA_set_default_method()\fR). For this reason, the \s-1ENGINE\s0 \s-1API\s0 is the
recommended way to control default implementations for use in \s-1RSA\s0 and other
cryptographic algorithms.
.SH "BUGS"
.IX Header "BUGS"
The behaviour of \fIRSA_flags()\fR is a mis-feature that is left as-is for now
to avoid creating compatibility problems. \s-1RSA\s0 functionality, such as the
encryption functions, are controlled by the \fBflags\fR value in the \s-1RSA\s0 key
itself, not by the \fBflags\fR value in the \s-1RSA_METHOD\s0 attached to the \s-1RSA\s0 key
(which is what this function returns). If the flags element of an \s-1RSA\s0 key
is changed, the changes will be honoured by \s-1RSA\s0 functionality but will not
be reflected in the return value of the \fIRSA_flags()\fR function \- in effect
\&\fIRSA_flags()\fR behaves more like an \fIRSA_default_flags()\fR function (which does
not currently exist).
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fIrsa\fR\|(3), \fIRSA_new\fR\|(3)
.SH "HISTORY"
.IX Header "HISTORY"
\&\fIRSA_new_method()\fR and \fIRSA_set_default_method()\fR appeared in SSLeay 0.8.
\&\fIRSA_get_default_method()\fR, \fIRSA_set_method()\fR and \fIRSA_get_method()\fR as
well as the rsa_sign and rsa_verify components of \s-1RSA_METHOD\s0 were
added in OpenSSL 0.9.4.
.PP
\&\fIRSA_set_default_openssl_method()\fR and \fIRSA_get_default_openssl_method()\fR
replaced \fIRSA_set_default_method()\fR and \fIRSA_get_default_method()\fR
respectively, and \fIRSA_set_method()\fR and \fIRSA_new_method()\fR were altered to use
\&\fB\s-1ENGINE\s0\fRs rather than \fB\s-1RSA_METHOD\s0\fRs during development of the engine
version of OpenSSL 0.9.6. For 0.9.7, the handling of defaults in the \s-1ENGINE\s0
\&\s-1API\s0 was restructured so that this change was reversed, and behaviour of the
other functions resembled more closely the previous behaviour. The
behaviour of defaults in the \s-1ENGINE\s0 \s-1API\s0 now transparently overrides the
behaviour of defaults in the \s-1RSA\s0 \s-1API\s0 without requiring changing these
function prototypes.
OpenPOWER on IntegriCloud