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76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/*
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** prrng.h -- NSPR Random Number Generator
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**
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**
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** lth. 29-Oct-1999.
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*/
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#ifndef prrng_h___
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#define prrng_h___
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#include "prtypes.h"
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PR_BEGIN_EXTERN_C
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/*
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** PR_GetRandomNoise() -- Get random noise from the host platform
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**
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** Description:
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** PR_GetRandomNoise() provides, depending on platform, a random value.
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** The length of the random value is dependent on platform and the
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** platform's ability to provide a random value at that moment.
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**
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** The intent of PR_GetRandomNoise() is to provide a "seed" value for a
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** another random number generator that may be suitable for
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** cryptographic operations. This implies that the random value
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** provided may not be, by itself, cryptographically secure. The value
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** generated by PR_GetRandomNoise() is at best, extremely difficult to
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** predict and is as non-deterministic as the underlying platfrom can
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** provide.
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**
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** Inputs:
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** buf -- pointer to a caller supplied buffer to contain the
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** generated random number. buf must be at least as large as
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** is specified in the 'size' argument.
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**
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** size -- the requested size of the generated random number
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**
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** Outputs:
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** a random number provided in 'buf'.
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**
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** Returns:
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** PRSize value equal to the size of the random number actually
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** generated, or zero. The generated size may be less than the size
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** requested. A return value of zero means that PR_GetRandomNoise() is
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** not implemented on this platform, or there is no available noise
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** available to be returned at the time of the call.
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**
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** Restrictions:
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** Calls to PR_GetRandomNoise() may use a lot of CPU on some platforms.
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** Some platforms may block for up to a few seconds while they
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** accumulate some noise. Busy machines generate lots of noise, but
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** care is advised when using PR_GetRandomNoise() frequently in your
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** application.
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**
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** History:
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** Parts of the model dependent implementation for PR_GetRandomNoise()
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** were taken in whole or part from code previously in Netscape's NSS
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** component.
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**
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*/
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NSPR_API(PRSize) PR_GetRandomNoise(
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void *buf,
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PRSize size
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);
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PR_END_EXTERN_C
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#endif /* prrng_h___ */
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/* end prrng.h */
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