$NetBSD: RAND_add.3,v 1.17 2018/02/08 21:57:26 christos Exp $
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Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
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Title "RAND_add 3"
way too many mistakes in technical documents.
Automatically generated by Pod::Man 4.07 (Pod::Simple 3.32)
Standard preamble:
========================================================================
..
.... Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
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Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
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Title "RAND_add 3"
RAND_add 3 "2018-01-15" "1.1.0g" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makesway too many mistakes in technical documents.
"NAME"
RAND_add, RAND_seed, RAND_status, RAND_event, RAND_screen - add
entropy to the PRNG
"LIBRARY"
libcrypto, -lcrypto
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1
#include <openssl/rand.h>
\&
void RAND_seed(const void *buf, int num);
\&
void RAND_add(const void *buf, int num, double entropy);
\&
int RAND_status(void);
\&
#if OPENSSL_API_COMPAT < 0x10100000L
int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam);
void RAND_screen(void);
#endif
.Ve
"DESCRIPTION"
Header "DESCRIPTION" \fIRAND_add() mixes the num bytes at buf into the \s-1PRNG\s0 state. Thus,
if the data at buf are unpredictable to an adversary, this
increases the uncertainty about the state and makes the \s-1PRNG\s0 output
less predictable. Suitable input comes from user interaction (random
key presses, mouse movements) and certain hardware events. The
\fBentropy argument is (the lower bound of) an estimate of how much
randomness is contained in buf, measured in bytes. Details about
sources of randomness and how to estimate their entropy can be found
in the literature, e.g. \s-1RFC 1750.\s0
\fIRAND_add() may be called with sensitive data such as user entered passwords. The seed values cannot be recovered from the \s-1PRNG\s0 output.
OpenSSL makes sure that the \s-1PRNG\s0 state is unique for each thread. On systems that provide \*(C`/dev/urandom\*(C', the randomness device is used to seed the \s-1PRNG\s0 transparently. However, on all other systems, the application is responsible for seeding the \s-1PRNG\s0 by calling RAND_add(), \fIRAND_egd\|(3) or RAND_load_file\|(3).
\fIRAND_seed() is equivalent to RAND_add() when num == entropy.
\fIRAND_event() and RAND_screen() are deprecated and should not be called.
"RETURN VALUES"
Header "RETURN VALUES" \fIRAND_status() returns 1 if the \s-1PRNG\s0 has been seeded
with enough data, 0 otherwise.
\fIRAND_event() calls RAND_poll() and returns RAND_status().
RAND_screen calls RAND_poll().
The other functions do not return values.
"HISTORY"
Header "HISTORY" \fIRAND_event() and RAND_screen() are deprecated since OpenSSL
1.1.0. Use the functions described above instead.
"SEE ALSO"
Header "SEE ALSO" \fIopenssl_rand\|(3), RAND_egd\|(3),
\fIRAND_load_file\|(3), RAND_cleanup\|(3)
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.