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
|
.\" Automatically generated by Pod::Man 2.25 (Pod::Simple 3.28)
.\"
.\" Standard preamble:
.\" ========================================================================
.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. \*(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-
.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\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el .ds Aq '
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD. Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.ie \nF \{\
. de IX
. tm Index:\\$1\t\\n%\t"\\$2"
..
. nr % 0
. rr F
.\}
.el \{\
. de IX
..
.\}
.\"
.\" 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 "dsa 3"
.TH dsa 3 "2014-10-15" "1.0.1j" "OpenSSL"
.\" For nroff, turn off justification. Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
dsa \- Digital Signature Algorithm
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\& #include <openssl/dsa.h>
\& #include <openssl/engine.h>
\&
\& DSA * DSA_new(void);
\& void DSA_free(DSA *dsa);
\&
\& int DSA_size(const DSA *dsa);
\&
\& DSA * DSA_generate_parameters(int bits, unsigned char *seed,
\& int seed_len, int *counter_ret, unsigned long *h_ret,
\& void (*callback)(int, int, void *), void *cb_arg);
\&
\& DH * DSA_dup_DH(const DSA *r);
\&
\& int DSA_generate_key(DSA *dsa);
\&
\& int DSA_sign(int dummy, const unsigned char *dgst, int len,
\& unsigned char *sigret, unsigned int *siglen, DSA *dsa);
\& int DSA_sign_setup(DSA *dsa, BN_CTX *ctx, BIGNUM **kinvp,
\& BIGNUM **rp);
\& int DSA_verify(int dummy, const unsigned char *dgst, int len,
\& const unsigned char *sigbuf, int siglen, DSA *dsa);
\&
\& void DSA_set_default_method(const DSA_METHOD *meth);
\& const DSA_METHOD *DSA_get_default_method(void);
\& int DSA_set_method(DSA *dsa, const DSA_METHOD *meth);
\& DSA *DSA_new_method(ENGINE *engine);
\& const DSA_METHOD *DSA_OpenSSL(void);
\&
\& int DSA_get_ex_new_index(long argl, char *argp, int (*new_func)(),
\& int (*dup_func)(), void (*free_func)());
\& int DSA_set_ex_data(DSA *d, int idx, char *arg);
\& char *DSA_get_ex_data(DSA *d, int idx);
\&
\& DSA_SIG *DSA_SIG_new(void);
\& void DSA_SIG_free(DSA_SIG *a);
\& int i2d_DSA_SIG(const DSA_SIG *a, unsigned char **pp);
\& DSA_SIG *d2i_DSA_SIG(DSA_SIG **v, unsigned char **pp, long length);
\&
\& DSA_SIG *DSA_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);
\& int DSA_do_verify(const unsigned char *dgst, int dgst_len,
\& DSA_SIG *sig, DSA *dsa);
\&
\& DSA * d2i_DSAPublicKey(DSA **a, unsigned char **pp, long length);
\& DSA * d2i_DSAPrivateKey(DSA **a, unsigned char **pp, long length);
\& DSA * d2i_DSAparams(DSA **a, unsigned char **pp, long length);
\& int i2d_DSAPublicKey(const DSA *a, unsigned char **pp);
\& int i2d_DSAPrivateKey(const DSA *a, unsigned char **pp);
\& int i2d_DSAparams(const DSA *a,unsigned char **pp);
\&
\& int DSAparams_print(BIO *bp, const DSA *x);
\& int DSAparams_print_fp(FILE *fp, const DSA *x);
\& int DSA_print(BIO *bp, const DSA *x, int off);
\& int DSA_print_fp(FILE *bp, const DSA *x, int off);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
These functions implement the Digital Signature Algorithm (\s-1DSA\s0). The
generation of shared \s-1DSA\s0 parameters is described in
\&\fIDSA_generate_parameters\fR\|(3);
\&\fIDSA_generate_key\fR\|(3) describes how to
generate a signature key. Signature generation and verification are
described in \fIDSA_sign\fR\|(3).
.PP
The \fB\s-1DSA\s0\fR structure consists of several \s-1BIGNUM\s0 components.
.PP
.Vb 10
\& struct
\& {
\& BIGNUM *p; // prime number (public)
\& BIGNUM *q; // 160\-bit subprime, q | p\-1 (public)
\& BIGNUM *g; // generator of subgroup (public)
\& BIGNUM *priv_key; // private key x
\& BIGNUM *pub_key; // public key y = g^x
\& // ...
\& }
\& DSA;
.Ve
.PP
In public keys, \fBpriv_key\fR is \s-1NULL\s0.
.PP
Note that \s-1DSA\s0 keys may use non-standard \fB\s-1DSA_METHOD\s0\fR implementations,
either directly or by the use of \fB\s-1ENGINE\s0\fR modules. In some cases (eg. an
\&\s-1ENGINE\s0 providing support for hardware-embedded keys), these \s-1BIGNUM\s0 values
will not be used by the implementation or may be used for alternative data
storage. For this reason, applications should generally avoid using \s-1DSA\s0
structure elements directly and instead use \s-1API\s0 functions to query or
modify keys.
.SH "CONFORMING TO"
.IX Header "CONFORMING TO"
\&\s-1US\s0 Federal Information Processing Standard \s-1FIPS\s0 186 (Digital Signature
Standard, \s-1DSS\s0), \s-1ANSI\s0 X9.30
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fIbn\fR\|(3), \fIdh\fR\|(3), \fIerr\fR\|(3), \fIrand\fR\|(3),
\&\fIrsa\fR\|(3), \fIsha\fR\|(3), \fIengine\fR\|(3),
\&\fIDSA_new\fR\|(3),
\&\fIDSA_size\fR\|(3),
\&\fIDSA_generate_parameters\fR\|(3),
\&\fIDSA_dup_DH\fR\|(3),
\&\fIDSA_generate_key\fR\|(3),
\&\fIDSA_sign\fR\|(3), \fIDSA_set_method\fR\|(3),
\&\fIDSA_get_ex_new_index\fR\|(3),
\&\fIRSA_print\fR\|(3)
|
