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Diffstat (limited to 'openssl/doc/crypto/RAND_egd.pod')
| -rw-r--r-- | openssl/doc/crypto/RAND_egd.pod | 88 |
1 files changed, 0 insertions, 88 deletions
diff --git a/openssl/doc/crypto/RAND_egd.pod b/openssl/doc/crypto/RAND_egd.pod deleted file mode 100644 index 80fa734..0000000 --- a/openssl/doc/crypto/RAND_egd.pod +++ /dev/null @@ -1,88 +0,0 @@ -=pod - -=head1 NAME - -RAND_egd, RAND_egd_bytes, RAND_query_egd_bytes - query entropy gathering daemon - -=head1 SYNOPSIS - - #include <openssl/rand.h> - - 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); - -=head1 DESCRIPTION - -RAND_egd() queries the entropy gathering daemon EGD on socket B<path>. -It queries 255 bytes and uses L<RAND_add(3)|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 the entropy gathering daemon EGD on socket B<path>. -It queries B<bytes> bytes and uses L<RAND_add(3)|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 entropy -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)|RAND_add(3)>. - -=head1 NOTES - -On systems without /dev/*random devices providing entropy from the kernel, -the EGD entropy gathering daemon can be used to collect entropy. It provides -a socket interface through which entropy 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 entropy from the -daemon using the daemon's "non-blocking read" command which shall -be answered immediately by the daemon without waiting for additional -entropy 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 entropy. - -OpenSSL automatically queries EGD when entropy 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. - -=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 -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. - -=head1 SEE ALSO - -L<rand(3)|rand(3)>, L<RAND_add(3)|RAND_add(3)>, -L<RAND_cleanup(3)|RAND_cleanup(3)> - -=head1 HISTORY - -RAND_egd() is available since OpenSSL 0.9.5. - -RAND_egd_bytes() is available since OpenSSL 0.9.6. - -RAND_query_egd_bytes() is available since OpenSSL 0.9.7. - -The automatic query of /var/run/egd-pool et al was added in OpenSSL 0.9.7. - -=cut |