001: /*
002: * @(#)DSAKeyPairGenerator.java 1.16 06/10/10
003: *
004: * Copyright 1990-2006 Sun Microsystems, Inc. All Rights Reserved.
005: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
006: *
007: * This program is free software; you can redistribute it and/or
008: * modify it under the terms of the GNU General Public License version
009: * 2 only, as published by the Free Software Foundation.
010: *
011: * This program is distributed in the hope that it will be useful, but
012: * WITHOUT ANY WARRANTY; without even the implied warranty of
013: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014: * General Public License version 2 for more details (a copy is
015: * included at /legal/license.txt).
016: *
017: * You should have received a copy of the GNU General Public License
018: * version 2 along with this work; if not, write to the Free Software
019: * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
020: * 02110-1301 USA
021: *
022: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
023: * Clara, CA 95054 or visit www.sun.com if you need additional
024: * information or have any questions.
025: *
026: */
027:
028: package java.security.interfaces;
029:
030: import java.security.*;
031:
032: /**
033: * An interface to an object capable of generating DSA key pairs.
034: *
035: * <p>The <code>initialize</code> methods may each be called any number
036: * of times. If no <code>initialize</code> method is called on a
037: * DSAKeyPairGenerator, the default is to generate 1024-bit keys, using
038: * precomputed p, q and g parameters and an instance of SecureRandom as
039: * the random bit source.
040: *
041: * <p>Users wishing to indicate DSA-specific parameters, and to generate a key
042: * pair suitable for use with the DSA algorithm typically
043: *
044: * <ol>
045: *
046: * <li>Get a key pair generator for the DSA algorithm by calling the
047: * KeyPairGenerator <code>getInstance</code> method with "DSA"
048: * as its argument.<p>
049: *
050: * <li>Initialize the generator by casting the result to a DSAKeyPairGenerator
051: * and calling one of the
052: * <code>initialize</code> methods from this DSAKeyPairGenerator interface.<p>
053: *
054: * <li>Generate a key pair by calling the <code>generateKeyPair</code>
055: * method from the KeyPairGenerator class.
056: *
057: * </ol>
058: *
059: * <p>Note: it is not always necessary to do do algorithm-specific
060: * initialization for a DSA key pair generator. That is, it is not always
061: * necessary to call an <code>initialize</code> method in this interface.
062: * Algorithm-independent initialization using the <code>initialize</code> method
063: * in the KeyPairGenerator
064: * interface is all that is needed when you accept defaults for algorithm-specific
065: * parameters.
066: *
067: * @see java.security.KeyPairGenerator
068: */
069: public interface DSAKeyPairGenerator {
070:
071: /**
072: * Initializes the key pair generator using p, q and g, the DSA
073: * family parameters.
074: *
075: * @param params the parameters to use to generate the keys.
076: *
077: * @param random the random bit source to use to generate
078: * key bits.
079: *
080: * @exception InvalidParameterException if the parameters passed are
081: * invalid or null.
082: */
083: public void initialize(DSAParams params, SecureRandom random)
084: throws InvalidParameterException;
085:
086: /**
087: * Initializes the key pair generator for a given modulus length,
088: * without parameters.
089: *
090: * <p>If <code>genParams</code> is true, this method will generate new
091: * p, q and g parameters. If it is false, the method will use precomputed
092: * parameters for the modulus length requested. If there are no
093: * precomputed parameters for that modulus length, an exception will be
094: * thrown. It is guaranteed that there will always be
095: * default parameters for modulus lengths of 512 and 1024 bits.
096: *
097: * @param modlen the modulus length, in bits. Valid values are any
098: * multiple of 8 between 512 and 1024, inclusive.
099: *
100: * @param random the random bit source to use to generate
101: * key bits.
102: *
103: * @param genParams whether or not to generate new parameters for
104: * the modulus length requested.
105: *
106: * @exception InvalidParameterException if the modulus length is not
107: * between 512 and 1024, or if genParams is false and there are
108: * not precomputed parameters for the modulus length requested.
109: */
110: public void initialize(int modlen, boolean genParams,
111: SecureRandom random) throws InvalidParameterException;
112: }
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