DES密码算法中进行16轮迭代运算时需要16轮子密钥，密钥初始材料为64位比特字节，本程序采用64个×××1、0代替二进制，模拟DES中16轮子密钥生成过程，这样可以形象观察其整个密钥生成过程。实际应用时只需要将int行改为byte行就行。
public class Key{
private final int SIZE=56;
private final int KEY_SIZE=48;
private int[] C=new int[28];
private int[] D=new int[28];
private int[] key=new int[SIZE];
private int[][] PRIVATE_KEY=new int[16][48];
private int[] IP_1=new int[]{
57,49,41,33,25,17,9,1,
58,50,42,34,26,18,10,2,
59,51,43,35,27,19,11,3,
60,52,44,36,63,55,47,39,
31,23,15,7,62,54,46,38,
30,22,14,6,61,53,45,37,
29,21,13,5,28,20,12,4
};
private int[] IP_2=new int[]{
14,17,11,24,1,5,
3,28,15,6,21,10,
23,19,12,4,26,8,
16,7,27,20,13,2,
41,52,31,37,47,55,
30,40,51,45,33,48,
44,49,39,56,34,53,
46,42,50,36,29,32
};
public Key(int[] k){
for(int i=0;i<SIZE;i++)
key[i]=k[IP_1[i]];
for(int i=0;i<28;i++){
C[i]=key[i];
D[i]=key[i+28];
}
}
public int[][] initKey(){
MoveKey();
return PRIVATE_KEY;
}
public void MoveKey(){
for(int i=0;i<16;i++){
int m=C[0],n=D[0],p=C[1],q=D[1];
int num=i;
for(int j=0;j<28;j++){
if(i==0||i==1||i==8||i==15){
if(j==27){
C[j]=m;
D[j]=n;
}
else{
C[j]=C[j+1];
D[j]=D[j+1];
}
}
else{
if(j==26){
C[j]=m;
D[j]=n;
}
else if(j==27){
C[j]=p;
D[j]=q;
}
else{
C[j]=C[j+2];
D[j]=D[j+2];
}
}
}
for(int l=0;l<KEY_SIZE;l++){
int temp=IP_2[l]-1;
if(temp<28)
PRIVATE_KEY[num][l]=C[temp];
else
PRIVATE_KEY[num][l]=D[temp-28];
}
}
}
public static void main(String[] str){
int[] test=new int[]{0,0,1,1,0,0,0,1,0,0,1,1,0,0,1,0,0,0,1,1,0,0,1,1,0,0,1,1,0,1,0,0,0,0,1,1,0,1,0,1,0,0,1,1,0,1,1,0,0,0,1,1,0,1,1,1,0,0,1,1,1,0,0,0};
Key k=new Key(test);
int[][] key=k.initKey();
for(int i=0;i<key.length;i++){
System.out.println("第"+(i+1)+"轮密钥: ");
for(int j=0;j<key[i].length;j++){
System.out.print(key[i][j]+" ");
}
System.out.println("");
}
}
}
