1 .\" Automatically generated by Pod::Man 2.27 (Pod::Simple 3.28)
4 .\" ========================================================================
5 .de Sp \" Vertical space (when we can't use .PP)
9 .de Vb \" Begin verbatim text
14 .de Ve \" End verbatim text
18 .\" Set up some character translations and predefined strings. \*(-- will
19 .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
20 .\" double quote, and \*(R" will give a right double quote. \*(C+ will
21 .\" give a nicer C++. Capital omega is used to do unbreakable dashes and
22 .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
23 .\" nothing in troff, for use with C<>.
25 .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
29 . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
30 . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
45 .\" Escape single quotes in literal strings from groff's Unicode transform.
49 .\" If the F register is turned on, we'll generate index entries on stderr for
50 .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
51 .\" entries marked with X<> in POD. Of course, you'll have to process the
52 .\" output yourself in some meaningful fashion.
54 .\" Avoid warning from groff about undefined register 'F'.
58 .if \n(.g .if rF .nr rF 1
59 .if (\n(rF:(\n(.g==0)) \{
62 . tm Index:\\$1\t\\n%\t"\\$2"
72 .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
73 .\" Fear. Run. Save yourself. No user-serviceable parts.
74 . \" fudge factors for nroff and troff
83 . ds #H ((1u-(\\\\n(.fu%2u))*.13m)
89 . \" simple accents for nroff and troff
99 . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
100 . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
101 . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
102 . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
103 . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
104 . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
106 . \" troff and (daisy-wheel) nroff accents
107 .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
108 .ds 8 \h'\*(#H'\(*b\h'-\*(#H'
109 .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
110 .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
111 .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
112 .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
113 .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
114 .ds ae a\h'-(\w'a'u*4/10)'e
115 .ds Ae A\h'-(\w'A'u*4/10)'E
116 . \" corrections for vroff
117 .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
118 .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
119 . \" for low resolution devices (crt and lpr)
120 .if \n(.H>23 .if \n(.V>19 \
133 .\" ========================================================================
135 .IX Title "RAND_set_rand_method 3"
136 .TH RAND_set_rand_method 3 "2015-01-08" "0.9.8zd" "OpenSSL"
137 .\" For nroff, turn off justification. Always turn off hyphenation; it makes
138 .\" way too many mistakes in technical documents.
142 RAND_set_rand_method, RAND_get_rand_method, RAND_SSLeay \- select RAND method
144 .IX Header "SYNOPSIS"
146 \& #include <openssl/rand.h>
148 \& void RAND_set_rand_method(const RAND_METHOD *meth);
150 \& const RAND_METHOD *RAND_get_rand_method(void);
152 \& RAND_METHOD *RAND_SSLeay(void);
155 .IX Header "DESCRIPTION"
156 A \fB\s-1RAND_METHOD\s0\fR specifies the functions that OpenSSL uses for random number
157 generation. By modifying the method, alternative implementations such as
158 hardware RNGs may be used. \s-1IMPORTANT:\s0 See the \s-1NOTES\s0 section for important
159 information about how these \s-1RAND API\s0 functions are affected by the use of
160 \&\fB\s-1ENGINE\s0\fR \s-1API\s0 calls.
162 Initially, the default \s-1RAND_METHOD\s0 is the OpenSSL internal implementation, as
163 returned by \fIRAND_SSLeay()\fR.
165 \&\fIRAND_set_default_method()\fR makes \fBmeth\fR the method for \s-1PRNG\s0 use. \fB\s-1NB\s0\fR: This is
166 true only whilst no \s-1ENGINE\s0 has been set as a default for \s-1RAND,\s0 so this function
167 is no longer recommended.
169 \&\fIRAND_get_default_method()\fR returns a pointer to the current \s-1RAND_METHOD.\s0
170 However, the meaningfulness of this result is dependent on whether the \s-1ENGINE
171 API\s0 is being used, so this function is no longer recommended.
172 .SH "THE RAND_METHOD STRUCTURE"
173 .IX Header "THE RAND_METHOD STRUCTURE"
175 \& typedef struct rand_meth_st
177 \& void (*seed)(const void *buf, int num);
178 \& int (*bytes)(unsigned char *buf, int num);
179 \& void (*cleanup)(void);
180 \& void (*add)(const void *buf, int num, int entropy);
181 \& int (*pseudorand)(unsigned char *buf, int num);
182 \& int (*status)(void);
186 The components point to the implementation of \fIRAND_seed()\fR,
187 \&\fIRAND_bytes()\fR, \fIRAND_cleanup()\fR, \fIRAND_add()\fR, \fIRAND_pseudo_rand()\fR
188 and \fIRAND_status()\fR.
189 Each component may be \s-1NULL\s0 if the function is not implemented.
191 .IX Header "RETURN VALUES"
192 \&\fIRAND_set_rand_method()\fR returns no value. \fIRAND_get_rand_method()\fR and
193 \&\fIRAND_SSLeay()\fR return pointers to the respective methods.
196 As of version 0.9.7, \s-1RAND_METHOD\s0 implementations are grouped together with other
197 algorithmic APIs (eg. \s-1RSA_METHOD, EVP_CIPHER,\s0 etc) in \fB\s-1ENGINE\s0\fR modules. If a
198 default \s-1ENGINE\s0 is specified for \s-1RAND\s0 functionality using an \s-1ENGINE API\s0 function,
199 that will override any \s-1RAND\s0 defaults set using the \s-1RAND API \s0(ie.
200 \&\fIRAND_set_rand_method()\fR). For this reason, the \s-1ENGINE API\s0 is the recommended way
201 to control default implementations for use in \s-1RAND\s0 and other cryptographic
204 .IX Header "SEE ALSO"
205 \&\fIrand\fR\|(3), \fIengine\fR\|(3)
208 \&\fIRAND_set_rand_method()\fR, \fIRAND_get_rand_method()\fR and \fIRAND_SSLeay()\fR are
209 available in all versions of OpenSSL.
211 In the engine version of version 0.9.6, \fIRAND_set_rand_method()\fR was altered to
212 take an \s-1ENGINE\s0 pointer as its argument. As of version 0.9.7, that has been
213 reverted as the \s-1ENGINE API\s0 transparently overrides \s-1RAND\s0 defaults if used,
214 otherwise \s-1RAND API\s0 functions work as before. \fIRAND_set_rand_engine()\fR was also
215 introduced in version 0.9.7.