s-des算法的Java实现和C++实现

public class SimpleDES { // Author: wangth // two keys K1 and K2 static int K1=0; static int K2=0; /*some parameters*/ static int P10[]=new int[]{3,5,2,7,4,10,1,9,8,6}; static int P8[]=new int[]{6,3,7,4,8,5,10,9}; static int P4[]=new int[]{2,4,3,1}; static int IP[]=new int[]{2,6,3,1,4,8,5,7}; static int IPI[]=new int[]{4,1,3,5,7,2,8,6}; static int EP[]=new int[]{4,1,2,3,2,3,4,1}; static int S0[][]={ {1,0,3,2}, {3,2,1,0}, {0,2,1,3}, {3,1,3,2}, }; static int S1[][]={ {0,1,2,3}, {2,0,1,3}, {3,0,1,0}, {2,1,0,3}, }; //根据数组交换 static int Permute(int num,int p[],int pmax){ int result=0; for(int i=0;i<p.length;i++){ result<<=1; result|=(num>>(pmax-p[i]))&1; } return result; } //生成k1,k2 static void SDES(String Key){ int K=Integer.parseInt(Key,2); K=Permute(K,P10,10); int th=0,tl=0; th=(K>>5)&0x1f;//取Key的高5位 tl=K&0x1f; //取Key的低5位 //LS-1 th=((th&0xf)<<1) | ((th & 0x10) >> 4);//循环左移一位 tl=((tl&0xf)<<1) | ((tl & 0x10) >> 4);//循环左移一位 K1=Permute(( th << 5)| tl,P8,10); //生成K1 //LS-2 th=((th & 0x07)<< 2) |((th & 0x18) >> 3);//循环左移二位 tl=((tl & 0x07)<< 2) |((tl & 0x18) >> 3);//循环左移二位 K2=Permute((th<<5) | tl,P8,10); //生成K2 } //f函数 static int F(int R,int K){ int t=Permute(R,EP,4)^K; int t0=(t>>4)& 0xf; int t1=t&0xf; t0= S0[((t0 & 0x8)>>2) | (t0 & 1)] [(t0>>1)&0x3]; t1= S1[((t1 & 0x8)>>2) | (t1 & 1)] [(t1>>1)&0x3]; t= Permute((t0<<2)|t1,P4,4); return t; } //fk函数 static int fk(int input,int k){ int l=(input>>4) & 0xf; int r=input & 0xf; return ((l^F(r,k))<< 4)| r; } //switch function static int SW(int x){ return ((x&0xf)<<4) | ((x>>4)&0xf); } //加密 static String encrypt(String input){ int m=Integer.parseInt(input, 2); m=Permute(m,IP,8); m=fk(m,K1); m=SW(m); m=fk(m,K2); m=Permute(m,IPI,8); return Integer.toString(m, 2); } //解密 static String decrypt(String input){ int m=Integer.parseInt(input, 2); m=Permute(m,IP,8); m=fk(m,K2); m=SW(m); m=fk(m,K1); m=Permute(m,IPI,8); return Integer.toString(m, 2); } public static void main(String[] args) { // TODO Auto-generated method stub String plaintext,ciphertext,key; int len=0; key="0111111101"; //加密 plaintext="01101111"; SDES(key); ciphertext=encrypt(plaintext); len=ciphertext.length(); //如果密文不足8位，补足8位 if(len<8){ for(int i=0;i<8-len;i++) ciphertext="0"+ciphertext; } System.out.println("对01101111加密后的密文为:"+ciphertext); //解密 ciphertext="01110110"; SDES(key); plaintext=decrypt(ciphertext); len=plaintext.length(); if(len<8){ for(int i=0;i<8-len;i++) plaintext="0"+plaintext; } System.out.println("对01110110解密后的明文为:"+plaintext); } }