1/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2/* This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5
6
7/*
8** prrng.h -- NSPR Random Number Generator
9**
10**
11** lth. 29-Oct-1999.
12*/
13
14#ifndef prrng_h___
15#define prrng_h___
16
17#include "prtypes.h"
18
19PR_BEGIN_EXTERN_C
20
21/*
22** PR_GetRandomNoise() -- Get random noise from the host platform
23**
24** Description:
25** PR_GetRandomNoise() provides, depending on platform, a random value.
26** The length of the random value is dependent on platform and the
27** platform's ability to provide a random value at that moment.
28**
29** The intent of PR_GetRandomNoise() is to provide a "seed" value for a
30** another random number generator that may be suitable for
31** cryptographic operations. This implies that the random value
32** provided may not be, by itself, cryptographically secure. The value
33** generated by PR_GetRandomNoise() is at best, extremely difficult to
34** predict and is as non-deterministic as the underlying platfrom can
35** provide.
36**
37** Inputs:
38** buf -- pointer to a caller supplied buffer to contain the
39** generated random number. buf must be at least as large as
40** is specified in the 'size' argument.
41**
42** size -- the requested size of the generated random number
43**
44** Outputs:
45** a random number provided in 'buf'.
46**
47** Returns:
48** PRSize value equal to the size of the random number actually
49** generated, or zero. The generated size may be less than the size
50** requested. A return value of zero means that PR_GetRandomNoise() is
51** not implemented on this platform, or there is no available noise
52** available to be returned at the time of the call.
53**
54** Restrictions:
55** Calls to PR_GetRandomNoise() may use a lot of CPU on some platforms.
56** Some platforms may block for up to a few seconds while they
57** accumulate some noise. Busy machines generate lots of noise, but
58** care is advised when using PR_GetRandomNoise() frequently in your
59** application.
60**
61** History:
62** Parts of the model dependent implementation for PR_GetRandomNoise()
63** were taken in whole or part from code previously in Netscape's NSS
64** component.
65**
66*/
67NSPR_API(PRSize) PR_GetRandomNoise(
68 void *buf,
69 PRSize size
70);
71
72PR_END_EXTERN_C
73
74#endif /* prrng_h___ */
75/* end prrng.h */
76

source code of include/nspr/prrng.h