16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.security.provider;
  27 
  28 import java.io.*;
  29 import java.net.*;
  30 import java.security.*;
  31 import java.util.Arrays;
  32 
  33 import sun.security.util.Debug;
  34 
  35 /**
  36  * Native PRNG implementation for Solaris/Linux/MacOS.
  37  * <p>
  38  * It obtains seed and random numbers by reading system files such as
  39  * the special device files /dev/random and /dev/urandom.  This
  40  * implementation respects the {@code securerandom.source} Security
  41  * property and {@code java.security.egd} System property for obtaining
  42  * seed material.  If the file specified by the properties does not
  43  * exist, /dev/random is the default seed source.  /dev/urandom is
  44  * the default source of random numbers.
  45  * <p>
  46  * On some Unix platforms, /dev/random may block until enough entropy is
  47  * available, but that may negatively impact the perceived startup
  48  * time.  By selecting these sources, this implementation tries to
  49  * strike a balance between performance and security.
  50  * <p>
  51  * generateSeed() and setSeed() attempt to directly read/write to the seed
  52  * source. However, this file may only be writable by root in many
  53  * configurations. Because we cannot just ignore bytes specified via
  54  * setSeed(), we keep a SHA1PRNG around in parallel.
  55  * <p>
  56  * nextBytes() reads the bytes directly from the source of random

  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.security.provider;
  27 
  28 import java.io.*;
  29 import java.net.*;
  30 import java.security.*;
  31 import java.util.Arrays;
  32 
  33 import sun.security.util.Debug;
  34 
  35 /**
  36  * Native PRNG implementation for Linux/MacOS.
  37  * <p>
  38  * It obtains seed and random numbers by reading system files such as
  39  * the special device files /dev/random and /dev/urandom.  This
  40  * implementation respects the {@code securerandom.source} Security
  41  * property and {@code java.security.egd} System property for obtaining
  42  * seed material.  If the file specified by the properties does not
  43  * exist, /dev/random is the default seed source.  /dev/urandom is
  44  * the default source of random numbers.
  45  * <p>
  46  * On some Unix platforms, /dev/random may block until enough entropy is
  47  * available, but that may negatively impact the perceived startup
  48  * time.  By selecting these sources, this implementation tries to
  49  * strike a balance between performance and security.
  50  * <p>
  51  * generateSeed() and setSeed() attempt to directly read/write to the seed
  52  * source. However, this file may only be writable by root in many
  53  * configurations. Because we cannot just ignore bytes specified via
  54  * setSeed(), we keep a SHA1PRNG around in parallel.
  55  * <p>
  56  * nextBytes() reads the bytes directly from the source of random