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1: /* DSSSignatureRawCodec.java -- 2: Copyright (C) 2001, 2002, 2003, 2006 Free Software Foundation, Inc. 3: 4: This file is a part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2 of the License, or (at 9: your option) any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; if not, write to the Free Software 18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 19: USA 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package gnu.java.security.sig.dss; 40: 41: import gnu.java.security.Registry; 42: import gnu.java.security.sig.ISignatureCodec; 43: 44: import java.io.ByteArrayOutputStream; 45: import java.math.BigInteger; 46: 47: /** 48: * An object that implements the {@link ISignatureCodec} operations for the 49: * <i>Raw</i> format to use with DSS signatures. 50: */ 51: public class DSSSignatureRawCodec 52: implements ISignatureCodec 53: { 54: public int getFormatID() 55: { 56: return RAW_FORMAT; 57: } 58: 59: /** 60: * Returns the encoded form of the designated DSS (Digital Signature Standard) 61: * signature object according to the <i>Raw</i> format supported by this 62: * library. 63: * <p> 64: * The <i>Raw</i> format for a DSA signature, in this implementation, is a 65: * byte sequence consisting of the following: 66: * <ol> 67: * <li>4-byte magic consisting of the value of the literal 68: * {@link Registry#MAGIC_RAW_DSS_SIGNATURE},</li> 69: * <li>1-byte version consisting of the constant: 0x01,</li> 70: * <li>4-byte count of following bytes representing the DSS parameter 71: * <code>r</code> in internet order,</li> 72: * <li>n-bytes representation of a {@link BigInteger} obtained by invoking 73: * the <code>toByteArray()</code> method on the DSS parameter <code>r</code>, 74: * </li> 75: * <li>4-byte count of following bytes representing the DSS parameter 76: * <code>s</code>,</li> 77: * <li>n-bytes representation of a {@link BigInteger} obtained by invoking 78: * the <code>toByteArray()</code> method on the DSS parameter <code>s</code>. 79: * </li> 80: * </ol> 81: * 82: * @param signature the signature to encode, consisting of the two DSS 83: * parameters <code>r</code> and <code>s</code> as a 84: * {@link BigInteger} array. 85: * @return the <i>Raw</i> format encoding of the designated signature. 86: * @exception IllegalArgumentException if the designated signature is not a 87: * DSS (Digital Signature Standard) one. 88: */ 89: public byte[] encodeSignature(Object signature) 90: { 91: BigInteger r, s; 92: try 93: { 94: BigInteger[] sig = (BigInteger[]) signature; 95: r = sig[0]; 96: s = sig[1]; 97: } 98: catch (Exception x) 99: { 100: throw new IllegalArgumentException("signature"); 101: } 102: ByteArrayOutputStream baos = new ByteArrayOutputStream(); 103: // magic 104: baos.write(Registry.MAGIC_RAW_DSS_SIGNATURE[0]); 105: baos.write(Registry.MAGIC_RAW_DSS_SIGNATURE[1]); 106: baos.write(Registry.MAGIC_RAW_DSS_SIGNATURE[2]); 107: baos.write(Registry.MAGIC_RAW_DSS_SIGNATURE[3]); 108: // version 109: baos.write(0x01); 110: // r 111: byte[] buffer = r.toByteArray(); 112: int length = buffer.length; 113: baos.write( length >>> 24); 114: baos.write((length >>> 16) & 0xFF); 115: baos.write((length >>> 8) & 0xFF); 116: baos.write(length & 0xFF); 117: baos.write(buffer, 0, length); 118: // s 119: buffer = s.toByteArray(); 120: length = buffer.length; 121: baos.write( length >>> 24); 122: baos.write((length >>> 16) & 0xFF); 123: baos.write((length >>> 8) & 0xFF); 124: baos.write(length & 0xFF); 125: baos.write(buffer, 0, length); 126: return baos.toByteArray(); 127: } 128: 129: public Object decodeSignature(byte[] k) 130: { 131: // magic 132: if (k[0] != Registry.MAGIC_RAW_DSS_SIGNATURE[0] 133: || k[1] != Registry.MAGIC_RAW_DSS_SIGNATURE[1] 134: || k[2] != Registry.MAGIC_RAW_DSS_SIGNATURE[2] 135: || k[3] != Registry.MAGIC_RAW_DSS_SIGNATURE[3]) 136: throw new IllegalArgumentException("magic"); 137: // version 138: if (k[4] != 0x01) 139: throw new IllegalArgumentException("version"); 140: 141: int i = 5; 142: int l; 143: byte[] buffer; 144: // r 145: l = k[i++] << 24 146: | (k[i++] & 0xFF) << 16 147: | (k[i++] & 0xFF) << 8 148: | (k[i++] & 0xFF); 149: buffer = new byte[l]; 150: System.arraycopy(k, i, buffer, 0, l); 151: i += l; 152: BigInteger r = new BigInteger(1, buffer); 153: // s 154: l = k[i++] << 24 155: | (k[i++] & 0xFF) << 16 156: | (k[i++] & 0xFF) << 8 157: | (k[i++] & 0xFF); 158: buffer = new byte[l]; 159: System.arraycopy(k, i, buffer, 0, l); 160: i += l; 161: BigInteger s = new BigInteger(1, buffer); 162: return new BigInteger[] { r, s }; 163: } 164: }