1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* 3 * The contents of this file are subject to the Mozilla Public 4 * License Version 1.1 (the "License"); you may not use this file 5 * except in compliance with the License. You may obtain a copy of 6 * the License at http://www.mozilla.org/MPL/ 7 * 8 * Software distributed under the License is distributed on an "AS 9 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or 10 * implied. See the License for the specific language governing 11 * rights and limitations under the License. 12 * 13 * The Original Code is the Netscape Portable Runtime (NSPR). 14 * 15 * The Initial Developer of the Original Code is Netscape 16 * Communications Corporation. Portions created by Netscape are 17 * Copyright (C) 1999-2000 Netscape Communications Corporation. All 18 * Rights Reserved. 19 * 20 * Contributor(s): 21 * 22 * Alternatively, the contents of this file may be used under the 23 * terms of the GNU General Public License Version 2 or later (the 24 * "GPL"), in which case the provisions of the GPL are applicable 25 * instead of those above. If you wish to allow use of your 26 * version of this file only under the terms of the GPL and not to 27 * allow others to use your version of this file under the MPL, 28 * indicate your decision by deleting the provisions above and 29 * replace them with the notice and other provisions required by 30 * the GPL. If you do not delete the provisions above, a recipient 31 * may use your version of this file under either the MPL or the 32 * GPL. 33 */ 34 35 36 /* 37 ** prrng.h -- NSPR Random Number Generator 38 ** 39 ** 40 ** lth. 29-Oct-1999. 41 */ 42 43 #ifndef prrng_h___ 44 #define prrng_h___ 45 46 #include "prtypes.h" 47 48 PR_BEGIN_EXTERN_C 49 50 /* 51 ** PR_GetRandomNoise() -- Get random noise from the host platform 52 ** 53 ** Description: 54 ** PR_GetRandomNoise() provides, depending on platform, a random value. 55 ** The length of the random value is dependent on platform and the 56 ** platform's ability to provide a random value at that moment. 57 ** 58 ** The intent of PR_GetRandomNoise() is to provide a "seed" value for a 59 ** another random number generator that may be suitable for 60 ** cryptographic operations. This implies that the random value 61 ** provided may not be, by itself, cryptographically secure. The value 62 ** generated by PR_GetRandomNoise() is at best, extremely difficult to 63 ** predict and is as non-deterministic as the underlying platfrom can 64 ** provide. 65 ** 66 ** Inputs: 67 ** buf -- pointer to a caller supplied buffer to contain the 68 ** generated random number. buf must be at least as large as 69 ** is specified in the 'size' argument. 70 ** 71 ** size -- the requested size of the generated random number 72 ** 73 ** Outputs: 74 ** a random number provided in 'buf'. 75 ** 76 ** Returns: 77 ** PRSize value equal to the size of the random number actually 78 ** generated, or zero. The generated size may be less than the size 79 ** requested. A return value of zero means that PR_GetRandomNoise() is 80 ** not implemented on this platform, or there is no available noise 81 ** available to be returned at the time of the call. 82 ** 83 ** Restrictions: 84 ** Calls to PR_GetRandomNoise() may use a lot of CPU on some platforms. 85 ** Some platforms may block for up to a few seconds while they 86 ** accumulate some noise. Busy machines generate lots of noise, but 87 ** care is advised when using PR_GetRandomNoise() frequently in your 88 ** application. 89 ** 90 ** History: 91 ** Parts of the model dependent implementation for PR_GetRandomNoise() 92 ** were taken in whole or part from code previously in Netscape's NSS 93 ** component. 94 ** 95 */ 96 NSPR_API(PRSize) PR_GetRandomNoise( 97 void *buf, 98 PRSize size 99 ); 100 101 PR_END_EXTERN_C 102 103 #endif /* prrng_h___ */ 104 /* end prrng.h */ 105
