update docs with descriptions and deprecation

[openssl.git] / doc / crypto / RAND_add.pod

diff --git a/doc/crypto/RAND_add.pod b/doc/crypto/RAND_add.pod
index fe539198019340db48d7030cbaaadf735107d365..cb8e781f76012cbbacf922aa19db58d6371cb948 100644 (file)
--- a/doc/crypto/RAND_add.pod
+++ b/doc/crypto/RAND_add.pod
@@ -2,7 +2,8 @@
 
 =head1 NAME
 
-RAND_add, RAND_seed, RAND_screen - Add entropy to the PRNG
+RAND_add, RAND_seed, RAND_status, RAND_event, RAND_screen - add
+entropy to the PRNG
 
 =head1 SYNOPSIS
 
@@ -10,9 +11,14 @@ RAND_add, RAND_seed, RAND_screen - Add entropy to the PRNG
 
  void RAND_seed(const void *buf, int num);
 
- void RAND_add(const void *buf, int num, int entropy);
+ 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
 
 =head1 DESCRIPTION
 
@@ -22,39 +28,52 @@ increases the uncertainty about the state and makes the PRNG output
 less predictable. Suitable input comes from user interaction (random
 key presses, mouse movements) and certain hardware events. The
 B<entropy> argument is (the lower bound of) an estimate of how much
-randomness is contained in B<buf>. Details about sources of randomness
-and how to estimate their entropy can be found in the literature,
-e.g. RFC 1750.
+randomness is contained in B<buf>, measured in bytes. Details about
+sources of randomness and how to estimate their entropy can be found
+in the literature, e.g. RFC 1750.
 
 RAND_add() may be called with sensitive data such as user entered
 passwords. The seed values cannot be recovered from the PRNG output.
 
 OpenSSL makes sure that the PRNG state is unique for each thread. On
-systems that provide C</dev/random>, the randomness device is used
+systems that provide C</dev/urandom>, the randomness device is used
 to seed the PRNG transparently. However, on all other systems, the
-application is responsible for seeding the PRNG by calling RAND_add()
-or RAND_load_file(3).
+application is responsible for seeding the PRNG by calling RAND_add(),
+L<RAND_egd(3)>
+or L<RAND_load_file(3)>.
 
 RAND_seed() is equivalent to RAND_add() when B<num == entropy>.
 
-The RAND_screen() function is available for the convenience of Windows
-programmers. It adds the current contents of the screen to the PRNG.
-For applications that can catch Windows events, seeding the PRNG with
-the parameters of B<WM_MOUSEMOVE> events is a significantly better
-source of randomness. It should be noted that both methods cannot be
-used on servers that run without user interaction.
+RAND_event() and RAND_screen() are deprecated and should not be called.
 
 =head1 RETURN VALUES
 
-These functions do not return values.
+RAND_status() returns 1 if the PRNG has been seeded
+with enough data, 0 otherwise.
 
-=head1 SEE ALSO
+RAND_event() calls RAND_poll() and returns RAND_status().
+
+RAND_screen calls RAND_poll().
 
-rand(3), RAND_load_file(3), RAND_cleanup(3)
+The other functions do not return values.
 
 =head1 HISTORY
 
-RAND_seed() and RAND_screen() are available in all versions of SSLeay
-and OpenSSL. RAND_add() was added in OpenSSL 0.9.5.
+RAND_event() and RAND_screen() are deprecated since OpenSSL
+1.1.  Use the functions described above instead.
+
+=head1 SEE ALSO
+
+L<rand(3)>, L<RAND_egd(3)>,
+L<RAND_load_file(3)>, L<RAND_cleanup(3)>
+
+=head1 COPYRIGHT
+
+Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the OpenSSL license (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
 
 =cut