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Diffstat (limited to 'gnu/java/security/util/Prime.java')
| -rw-r--r-- | gnu/java/security/util/Prime.java | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/gnu/java/security/util/Prime.java b/gnu/java/security/util/Prime.java new file mode 100644 index 000000000..abcaf076f --- /dev/null +++ b/gnu/java/security/util/Prime.java @@ -0,0 +1,145 @@ +/* Prime.java --- Prime number generation utilities
+
+ Copyright (c) 1999 by Free Software Foundation, Inc.
+ Written by Mark Benvenuto <ivymccough@worldnet.att.net>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU Library General Public License as published
+ by the Free Software Foundation, version 2. (see COPYING.LIB)
+
+ This program 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 this program; if not, write to the Free Software Foundation
+ Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307 USA. */
+
+package gnu.java.security.util;
+import java.math.BigInteger;
+import java.util.Random;
+//import java.security.SecureRandom;
+
+public final class Prime
+{
+
+/*
+ See IEEE P1363 A.15.4 (10/05/98 Draft)
+*/
+public static BigInteger generateRandomPrime( int pmin, int pmax, BigInteger f )
+{
+ BigInteger d;
+
+ //Step 1 - generate prime
+ BigInteger p = new BigInteger( (pmax + pmin)/2, new Random() );
+ if( p.compareTo( BigInteger.valueOf( 1 ).shiftLeft( pmin ) ) <= 0 )
+ {
+ p.add( BigInteger.valueOf( 1 ).shiftLeft( pmin ).subtract( p ) );
+ }
+
+ //Step 2 - test for even
+ if( p.mod( BigInteger.valueOf(2) ).compareTo( BigInteger.valueOf( 0 )) == 0)
+ p.add( BigInteger.valueOf( 1 ) );
+
+ for(;;)
+ {
+ //Step 3
+ if( p.compareTo( BigInteger.valueOf( 1 ).shiftLeft( pmax)) > 0)
+ {
+ //Step 3.1
+ p = p.subtract( BigInteger.valueOf( 1 ).shiftLeft( pmax) );
+ p = p.add( BigInteger.valueOf( 1 ).shiftLeft( pmin) );
+ p = p.subtract( BigInteger.valueOf( 1 ) );
+
+ //Step 3.2
+ // put step 2 code here so looping code is cleaner
+ //Step 2 - test for even
+ if( p.mod( BigInteger.valueOf(2) ).compareTo( BigInteger.valueOf( 0 )) == 0)
+ p.add( BigInteger.valueOf( 1 ) );
+ continue;
+ }
+
+ //Step 4 - compute GCD
+ d = p.subtract( BigInteger.valueOf(1) );
+ d = d.gcd( f );
+
+ //Step 5 - test d
+ if( d.compareTo( BigInteger.valueOf( 1 ) ) == 0)
+ {
+ //Step 5.1 - test primality
+ if( p.isProbablePrime( 1 ) == true )
+ {
+ //Step 5.2;
+ return p;
+ }
+ }
+ //Step 6
+ p = p.add( BigInteger.valueOf( 2 ) );
+
+ //Step 7
+ }
+}
+
+
+/*
+ See IEEE P1363 A.15.5 (10/05/98 Draft)
+*/
+public static BigInteger generateRandomPrime( BigInteger r, BigInteger a, int pmin, int pmax, BigInteger f )
+{
+ BigInteger d, w;
+
+ //Step 1 - generate prime
+ BigInteger p = new BigInteger( (pmax + pmin)/2, new Random() );
+
+steptwo:{ //Step 2
+ w = p.mod( r.multiply( BigInteger.valueOf(2) ));
+
+ //Step 3
+ p = p.add( r.multiply( BigInteger.valueOf(2) ) );
+ p = p.subtract( w );
+ p = p.add(a);
+
+ //Step 4 - test for even
+ if( p.mod( BigInteger.valueOf(2) ).compareTo( BigInteger.valueOf( 0 )) == 0)
+ p.add( r );
+
+ for(;;)
+ {
+ //Step 5
+ if( p.compareTo( BigInteger.valueOf( 1 ).shiftLeft( pmax)) > 0)
+ {
+ //Step 5.1
+ p = p.subtract( BigInteger.valueOf( 1 ).shiftLeft( pmax) );
+ p = p.add( BigInteger.valueOf( 1 ).shiftLeft( pmin) );
+ p = p.subtract( BigInteger.valueOf( 1 ) );
+
+ //Step 5.2 - goto to Step 2
+ break steptwo;
+ }
+
+ //Step 6
+ d = p.subtract( BigInteger.valueOf(1) );
+ d = d.gcd( f );
+
+ //Step 7 - test d
+ if( d.compareTo( BigInteger.valueOf( 1 ) ) == 0)
+ {
+ //Step 7.1 - test primality
+ if( p.isProbablePrime( 1 ) == true )
+ {
+ //Step 7.2;
+ return p;
+ }
+ }
+ //Step 8
+ p = p.add( r.multiply( BigInteger.valueOf(2) ) );
+
+ //Step 9
+ }
+ }
+ //Should never reach here but makes the compiler happy
+ return BigInteger.valueOf(0);
+}
+
+}
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