| /* SHA1PRNG.java --- Secure Random SPI SHA1PRNG |
| Copyright (C) 1999 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| As a special exception, if you link this library with other files to |
| produce an executable, this library does not by itself cause the |
| resulting executable to be covered by the GNU General Public License. |
| This exception does not however invalidate any other reasons why the |
| executable file might be covered by the GNU General Public License. */ |
| |
| |
| package gnu.java.security.provider; |
| |
| import java.util.Random; |
| // import java.security.SecureRandomSpi; |
| import java.security.MessageDigest; |
| import java.security.NoSuchAlgorithmException; |
| import java.io.Serializable; |
| |
| // public class SHA1PRNG extends SecureRandomSpi implements Serializable |
| public class SHA1PRNG implements Serializable |
| { |
| MessageDigest digest; |
| byte seed[]; |
| byte data[]; |
| int seedpos; |
| int datapos; |
| |
| public SHA1PRNG() |
| { |
| try { |
| digest = MessageDigest.getInstance("SHA"); |
| } catch ( NoSuchAlgorithmException nsae) { |
| System.out.println("Failed to find SHA Message Digest: " + nsae); |
| nsae.printStackTrace(); |
| } |
| |
| seed = new byte[20]; |
| seedpos = 0; |
| data = new byte[40]; |
| datapos = 0; |
| |
| new Random().nextBytes(seed); |
| |
| byte digestdata[]; |
| digestdata = digest.digest( data ); |
| System.arraycopy( digestdata, 0, data, 0, 20); |
| |
| } |
| |
| public void engineSetSeed(byte[] seed) |
| { |
| for(int i = 0; i < seed.length; i++) |
| this.seed[seedpos++ % 20] ^= seed[i]; |
| seedpos %= 20; |
| |
| } |
| |
| public void engineNextBytes(byte[] bytes) |
| { |
| |
| if( bytes.length < (20 - datapos) ) { |
| System.arraycopy( bytes, 0, data, datapos, bytes.length); |
| datapos += bytes.length; |
| return; |
| } |
| |
| int i, blen = bytes.length, bpos = 0; |
| byte digestdata[]; |
| while( bpos < blen ) { |
| i = 20 - datapos; |
| System.arraycopy( bytes, bpos, data, datapos, i); |
| bpos += i; |
| datapos += i; |
| if( datapos >= 20) { |
| //System.out.println( (0 + 20) + "\n" + (20 + 20) ); |
| System.arraycopy( seed, 0, data, 20, 20); |
| digestdata = digest.digest( data ); |
| System.arraycopy( digestdata, 0, data, 0, 20); |
| datapos = 0; |
| } |
| } |
| |
| } |
| |
| public byte[] engineGenerateSeed(int numBytes) |
| { |
| byte tmp[] = new byte[numBytes]; |
| |
| engineNextBytes( tmp ); |
| return tmp; |
| } |
| } |