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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Netscape security libraries.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998-2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License Version 2 or later (the
* "GPL"), in which case the provisions of the GPL are applicable
* instead of those above. If you wish to allow use of your
* version of this file only under the terms of the GPL and not to
* allow others to use your version of this file under the MPL,
* indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the
* GPL.
*/
/*
** prrng.h -- NSPR Random Number Generator
**
**
** lth. 29-Oct-1999.
*/
#ifndef prrng_h___
#define prrng_h___
#include "prtypes.h"
PR_BEGIN_EXTERN_C
/*
** PR_GetRandomNoise() -- Get random noise from the host platform
**
** Description:
** PR_GetRandomNoise() provides, depending on platform, a random value.
** The length of the random value is dependent on platform and the
** platform's ability to provide a random value at that moment.
**
** The intent of PR_GetRandomNoise() is to provide a "seed" value for a
** another random number generator that may be suitable for
** cryptographic operations. This implies that the random value
** provided may not be, by itself, cryptographically secure. The value
** generated by PR_GetRandomNoise() is at best, extremely difficult to
** predict and is as non-deterministic as the underlying platfrom can
** provide.
**
** Inputs:
** buf -- pointer to a caller supplied buffer to contain the
** generated random number. buf must be at least as large as
** is specified in the 'size' argument.
**
** size -- the requested size of the generated random number
**
** Outputs:
** a random number provided in 'buf'.
**
** Returns:
** PRSize value equal to the size of the random number actually
** generated, or zero. The generated size may be less than the size
** requested. A return value of zero means that PR_GetRandomNoise() is
** not implemented on this platform, or there is no available noise
** available to be returned at the time of the call.
**
** Restrictions:
** Calls to PR_GetRandomNoise() may use a lot of CPU on some platforms.
** Some platforms may block for up to a few seconds while they
** accumulate some noise. Busy machines generate lots of noise, but
** care is advised when using PR_GetRandomNoise() frequently in your
** application.
**
** History:
** Parts of the model dependent implementation for PR_GetRandomNoise()
** were taken in whole or part from code previously in Netscape's NSS
** component.
**
*/
NSPR_API(PRSize) PR_GetRandomNoise(
void *buf,
PRSize size
);
PR_END_EXTERN_C
#endif /* prrng_h___ */
/* end prrng.h */
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