1 package org.bouncycastle.crypto.generators; 2 3 import org.bouncycastle.crypto.KeyGenerationParameters; 4 import org.bouncycastle.crypto.params.DESedeParameters; 5 6 public class DESedeKeyGenerator 7 extends DESKeyGenerator 8 { 9 /** 10 * initialise the key generator - if strength is set to zero 11 * the key generated will be 192 bits in size, otherwise 12 * strength can be 128 or 192 (or 112 or 168 if you don't count 13 * parity bits), depending on whether you wish to do 2-key or 3-key 14 * triple DES. 15 * 16 * @param param the parameters to be used for key generation 17 */ 18 public void init( 19 KeyGenerationParameters param) 20 { 21 this.random = param.getRandom(); 22 this.strength = (param.getStrength() + 7) / 8; 23 24 if (strength == 0 || strength == (168 / 8)) 25 { 26 strength = DESedeParameters.DES_EDE_KEY_LENGTH; 27 } 28 else if (strength == (112 / 8)) 29 { 30 strength = 2 * DESedeParameters.DES_KEY_LENGTH; 31 } 32 else if (strength != DESedeParameters.DES_EDE_KEY_LENGTH 33 && strength != (2 * DESedeParameters.DES_KEY_LENGTH)) 34 { 35 throw new IllegalArgumentException("DESede key must be " 36 + (DESedeParameters.DES_EDE_KEY_LENGTH * 8) + " or " 37 + (2 * 8 * DESedeParameters.DES_KEY_LENGTH) 38 + " bits long."); 39 } 40 } 41 42 public byte[] generateKey() 43 { 44 byte[] newKey = new byte[strength]; 45 46 do 47 { 48 random.nextBytes(newKey); 49 50 DESedeParameters.setOddParity(newKey); 51 } 52 while (DESedeParameters.isWeakKey(newKey, 0, newKey.length)); 53 54 return newKey; 55 } 56 } 57
