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/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(),
-L<RAND_egd(3)>
-or L<RAND_load_file(3)>.
-
RAND_seed() is equivalent to RAND_add() with B<randomness> set to B<num>.
+On systems that provide C</dev/urandom> or similar source of randomess,
+it will be used
+to seed the PRNG transparently. On older systems, however, it might
+be necessary to use RAND_add(), L<RAND_egd(3)> or L<RAND_load_file(3)>.
+
RAND_event() and RAND_screen() are deprecated and should not be called.
=head1 RETURN VALUES
=head1 SEE ALSO
L<RAND_bytes(3)>, L<RAND_egd(3)>,
-L<RAND_load_file(3)>, L<RAND_cleanup(3)>
+L<RAND_load_file(3)>
=head1 COPYRIGHT
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2017 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
=head1 DESCRIPTION
-Prior to OpenSSL 1.1.0 RAND_cleanup() erases the memory used by the PRNG. This
-function is deprecated and as of version 1.1.0 does nothing. No explicit
-initialisation or de-initialisation is necessary. See L<OPENSSL_init_crypto(3)>.
+Prior to OpenSSL 1.1.0, RAND_cleanup() released all resources used by
+the PRNG. As of version 1.1.0, it does nothing and should not be called,
+since since no explicit initialisation or de-initialisation is necessary. See
+L<OPENSSL_init_crypto(3)>.
=head1 RETURN VALUE
=head1 COPYRIGHT
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2017 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
#include <openssl/rand.h>
+ int RAND_egd_bytes(const char *path, int num);
int RAND_egd(const char *path);
- int RAND_egd_bytes(const char *path, int bytes);
- int RAND_query_egd_bytes(const char *path, unsigned char *buf, int bytes);
+ int RAND_query_egd_bytes(const char *path, unsigned char *buf, int num);
=head1 DESCRIPTION
-RAND_egd() queries the Entropy Gathering Daemon (EGD) on socket B<path>.
-It queries 255 bytes and uses L<RAND_add(3)> to seed the
-OpenSSL built-in PRNG. RAND_egd(path) is a wrapper for
-RAND_egd_bytes(path, 255);
-
-RAND_egd_bytes() queries EGD on socket B<path>.
-It queries B<bytes> bytes and uses L<RAND_add(3)> to seed the
-OpenSSL built-in PRNG.
-This function is more flexible than RAND_egd().
-When only one secret key must
-be generated, it is not necessary to request the full amount 255 bytes from
-the EGD socket. This can be advantageous, since the amount of randomness
-that can be retrieved from EGD over time is limited.
-
-RAND_query_egd_bytes() performs the actual query of the EGD daemon on socket
-B<path>. If B<buf> is given, B<bytes> bytes are queried and written into
-B<buf>. If B<buf> is NULL, B<bytes> bytes are queried and used to seed the
-OpenSSL built-in PRNG using L<RAND_add(3)>.
-
-=head1 NOTES
-
-On systems without /dev/*random devices providing randomness from the kernel,
-EGD provides
-a socket interface through which randomness can be gathered in chunks up to
-255 bytes. Several chunks can be queried during one connection.
-
-EGD is available from http://www.lothar.com/tech/crypto/ (C<perl
-Makefile.PL; make; make install> to install). It is run as B<egd>
-I<path>, where I<path> is an absolute path designating a socket. When
-RAND_egd() is called with that path as an argument, it tries to read
-random bytes that EGD has collected. RAND_egd() retrieves randomness from the
-daemon using the daemon's "non-blocking read" command which shall
-be answered immediately by the daemon without waiting for additional
-randomness to be collected. The write and read socket operations in the
-communication are blocking.
-
-Alternatively, the EGD-interface compatible daemon PRNGD can be used. It is
-available from
-http://prngd.sourceforge.net/ .
-PRNGD does employ an internal PRNG itself and can therefore never run
-out of randomness.
-
-OpenSSL automatically queries EGD when randomness is requested via RAND_bytes()
-or the status is checked via RAND_status() for the first time, if the socket
-is located at /var/run/egd-pool, /dev/egd-pool or /etc/egd-pool.
+On older platforms without a good source of randomness such as C</dev/urandom>,
+it is possible to query an Entropy Gathering Daemon (EGD) over a local
+socket to obtain randomness and seed the OpenSSL RNG.
+The protocol used is defined by the EGDs available at
+L<http://egd.sourceforge.net/> or L<http://prngd.sourceforge.net>.
+
+RAND_egd_bytes() requests B<num> bytes of randomness from an EGD at the
+specified socket B<path>, and passes the data it receives into RAND_add().
+RAND_egd() is equivalent to RAND_egd_bytes() with B<num> set to 255.
+
+RAND_query_egd_bytes() requests B<num> bytes of randomness from an EGD at
+the specified socket B<path>.
+If B<buf> is B<NULL>, it is equivalent to RAND_egd_bytes().
+If B<buf> is not B<NULL>, then the data is copied to the buffer and
+RAND_add() is not called.
+
+OpenSSL can be configured at build time to try to use the EGD for seeding
+automatically.
=head1 RETURN VALUE
RAND_egd() and RAND_egd_bytes() return the number of bytes read from the
-daemon on success, and -1 if the connection failed or the daemon did not
+daemon on success, or -1 if the connection failed or the daemon did not
return enough data to fully seed the PRNG.
RAND_query_egd_bytes() returns the number of bytes read from the daemon on
-success, and -1 if the connection failed. The PRNG state is not considered.
+success, or -1 if the connection failed.
=head1 SEE ALSO
-L<RAND_bytes(3)>, L<RAND_add(3)>,
-L<RAND_cleanup(3)>
+L<RAND_bytes(3)>, L<RAND_add(3)>
=head1 COPYRIGHT
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2017 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
=head1 SEE ALSO
-L<RAND_bytes(3)>, L<RAND_add(3)>, L<RAND_cleanup(3)>
+L<RAND_bytes(3)>, L<RAND_add(3)>
=head1 HISTORY
=head1 COPYRIGHT
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2017 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
#include <openssl/rand.h>
+ RAND_METHOD *RAND_OpenSSL(void);
+
void RAND_set_rand_method(const RAND_METHOD *meth);
const RAND_METHOD *RAND_get_rand_method(void);
- RAND_METHOD *RAND_OpenSSL(void);
-
=head1 DESCRIPTION
A B<RAND_METHOD> specifies the functions that OpenSSL uses for random number
-generation. By modifying the method, alternative implementations such as
-hardware RNGs may be used. IMPORTANT: See the NOTES section for important
-information about how these RAND API functions are affected by the use of
-B<ENGINE> API calls.
+generation.
-Initially, the default RAND_METHOD is the OpenSSL internal implementation, as
-returned by RAND_OpenSSL().
+Initially, the default B<RAND_METHOD> is the OpenSSL internal implementation,
+as returned by RAND_OpenSSL().
+This implementation ensures that the PRNG state is unique for each thread.
-RAND_set_default_method() makes B<meth> the method for PRNG use. B<NB>: This is
-true only whilst no ENGINE has been set as a default for RAND, so this function
-is no longer recommended.
+If an B<ENGINE> is loaded that provides the RAND API, however, it will
+be used instead of the method returned by RAND_OpenSSL().
-RAND_get_default_method() returns a pointer to the current RAND_METHOD.
-However, the meaningfulness of this result is dependent on whether the ENGINE
-API is being used, so this function is no longer recommended.
+RAND_set_rand_method() makes B<meth> the method for PRNG use. If an
+ENGINE was providing the method, it will be released first.
+
+RAND_get_rand_method() returns a pointer to the current B<RAND_METHOD>.
=head1 THE RAND_METHOD STRUCTURE
- typedef struct rand_meth_st
- {
+ typedef struct rand_meth_st {
void (*seed)(const void *buf, int num);
int (*bytes)(unsigned char *buf, int num);
void (*cleanup)(void);
int (*status)(void);
} RAND_METHOD;
-The components point to method implementations used by (or called by), in order,
+The fields point to functions that are used by, in order,
RAND_seed(), RAND_bytes(), internal RAND cleanup, RAND_add(), RAND_pseudo_rand()
and RAND_status().
-Each component may be NULL if the function is not implemented.
+Each pointer may be NULL if the function is not implemented.
=head1 RETURN VALUES
RAND_set_rand_method() returns no value. RAND_get_rand_method() and
RAND_OpenSSL() return pointers to the respective methods.
-=head1 NOTES
-
-RAND_METHOD implementations are grouped together with other
-algorithmic APIs (eg. RSA_METHOD, EVP_CIPHER, etc) in B<ENGINE> modules. If a
-default ENGINE is specified for RAND functionality using an ENGINE API function,
-that will override any RAND defaults set using the RAND API (ie.
-RAND_set_rand_method()). For this reason, the ENGINE API is the recommended way
-to control default implementations for use in RAND and other cryptographic
-algorithms.
-
=head1 SEE ALSO
L<RAND_bytes(3)>, L<ENGINE_by_id(3)>
=head1 COPYRIGHT
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2017 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
projects / oweals / openssl.git / commitdiff