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
|
<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<refentry xml:id="function.openssl-random-pseudo-bytes" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>openssl_random_pseudo_bytes</refname>
<refpurpose>Generate a pseudo-random string of bytes</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>string</type><methodname>openssl_random_pseudo_bytes</methodname>
<methodparam><type>int</type><parameter>length</parameter></methodparam>
<methodparam choice="opt"><type>bool</type><parameter role="reference">strong_result</parameter><initializer>&null;</initializer></methodparam>
</methodsynopsis>
<para>
Generates a <type>string</type> of pseudo-random bytes, with the number of bytes
determined by the <parameter>length</parameter> parameter.
</para>
<para>
It also indicates if a cryptographically strong algorithm was used to produce the
pseudo-random bytes, and does this via the optional <parameter>strong_result</parameter>
parameter. It's rare for this to be &false;, but some systems may be broken or old.
</para>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>length</parameter></term>
<listitem>
<para>
The length of the desired string of bytes. Must be a positive integer less than or equal to <literal>2147483647</literal>. PHP will
try to cast this parameter to a non-null integer to use it.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>strong_result</parameter></term>
<listitem>
<para>
If passed into the function, this will hold a <type>bool</type> value that determines
if the algorithm used was "cryptographically strong", e.g., safe for usage with GPG,
passwords, etc. &true; if it did, otherwise &false;
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
Returns the generated &string; of bytes.
</para>
</refsect1>
<refsect1 role="errors">
&reftitle.errors;
<para>
<function>openssl_random_pseudo_bytes</function> throws an <classname>Exception</classname>
on failure.
</para>
</refsect1>
<refsect1 role="changelog">
&reftitle.changelog;
<informaltable>
<tgroup cols="2">
<thead>
<row>
<entry>&Version;</entry>
<entry>&Description;</entry>
</row>
</thead>
<tbody>
<row>
<entry>8.0.0</entry>
<entry>
<parameter>strong_result</parameter> is nullable now.
</entry>
</row>
<row>
<entry>7.4.0</entry>
<entry>
The function no longer returns &false; on failure, but throws an <classname>Exception</classname> instead.
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title><function>openssl_random_pseudo_bytes</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
for ($i = 1; $i <= 4; $i++) {
$bytes = openssl_random_pseudo_bytes($i, $cstrong);
$hex = bin2hex($bytes);
echo "Lengths: Bytes: $i and Hex: " . strlen($hex) . PHP_EOL;
var_dump($hex);
var_dump($cstrong);
echo PHP_EOL;
}
?>
]]>
</programlisting>
&example.outputs.similar;
<screen>
<![CDATA[
Lengths: Bytes: 1 and Hex: 2
string(2) "42"
bool(true)
Lengths: Bytes: 2 and Hex: 4
string(4) "dc6e"
bool(true)
Lengths: Bytes: 3 and Hex: 6
string(6) "288591"
bool(true)
Lengths: Bytes: 4 and Hex: 8
string(8) "ab86d144"
bool(true)
]]>
</screen>
</example>
</para>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<simplelist>
<member><function>random_bytes</function></member>
<member><function>bin2hex</function></member>
<member><function>crypt</function></member>
<member><function>random_int</function></member>
</simplelist>
</refsect1>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->
|
