SM4加解密
SM4加解密
sm4是一种分组密码，分组长度和密钥长度都为128比特
相关算法
- s盒代换：以字节为单位进行非线性替换，输入字节的前四位和后四位确定s盒中替换的字节。
如：若输入e2则代换为f2
| --- | 2 | 3 |
|---|---|---|
| e | f2 | a3 |
| 6 | 71 | 32 |
- 线性变化：主要是移位运算和异或运算，输入输出都为32位。例如B为32位，则运算为B⊕(B<<<2) ⊕(B<<<10) ⊕(B<<<18) ⊕(B<<<24)
- 密钥扩展算法：输入128位的密钥，进行32轮迭代，每一轮产生一个32位的轮密钥，共产生32个轮密钥。先进行(k0,k1,k2,k3)=(mk0⊕fk0,mk1⊕fk1,mk2⊕fk2, mk3⊕fk3),然后进行32轮迭代，每一轮为rki=ki+4=ki⊕t’(ki+1⊕ki+2⊕ki+3⊕cki)
其中rki为i轮的密钥，cki与fki都为常数，t’运算为先进行s盒代换，然后进行线性变化，只不过这里的线性变化为B⊕(B<<<13) ⊕(B<<<23)。 - 加密算法：输入为128位，即4个32位的字，输出也为128位。共有32轮迭代，每一轮使用一个32位的轮密钥。每一轮的运算为x0⊕t(x1⊕x2⊕x3⊕rk)。之后将得到的x35,x34,x33,x32再进行一个反序处理，作为密文。
其中rk为该轮轮密钥，x0,x1,x2,x3为4个32位的字，t运算包含s盒代换和线性变换，即每一轮的运算为x0⊕[s(B)] ⊕[s(B)<<<2] ⊕[s(B)<<<10] ⊕[s(B)<<<18] ⊕ [s(B)<<<24] ,B为x1⊕x2⊕x3⊕rk - 解密算法：与加密算法相同。只是轮密钥的使用顺序相反。
实现说明
- 密钥生成采用java中内置的能生成强伪随机数的函数
SecureRandom random = new SecureRandom(); random.nextBytes(key_byte);
需要导入import java.security.SecureRandom; - 生成的密钥及密文都以整数的形式输出，因为Java的int等数据类型都为无符号的，所以可能有负值
- 程序只是对一个分组进行加解密，不涉及cbc等分组模式
源代码
加密
package sm4;
import java.security.SecureRandom;
import java.util.Scanner;
public class sm4 {
public static void main(String[] args) {
int strint[]=new int[36];
int m=0;
int n=0;
int s=0;
int key_int[]=new int[4];
byte key_byte[]=new byte [16];
int key_kozhan[]=new int[32];
char miwen[]=new char[16];
//输入16个字符
System.out.println("请输入16个字符 ");
Scanner in = new Scanner(System.in);
String str = in.next();//获得输入的字符串
byte strbyte[] = str.getBytes();//将字符串转换为Byte数组
//将8位的Byte数组，4个4个合并，合并为4个32位的字
while(m<4) {
strint[m]=kozhan(strbyte[4*m],strbyte[4*m+1],strbyte[4*m+2],strbyte[4*m+3]);
m++;
}
//用java自带的函数生成强伪随机数
SecureRandom random = new SecureRandom();
random.nextBytes(key_byte);
//将8位的密钥Byte数组，4个4个合并，合并为4个32位的字
while(n<4) {
key_int[n]=kozhan(key_byte[4*n],key_byte[4*n+1],key_byte[4*n+2],key_byte[4*n+3]);
n++;
}
System.out.print("密钥为");
for(int i=0;i<4;i++) {
System.out.print(key_int[i]+" ");
}
//密钥扩展
key_kozhan=key_kozhan(key_int);
//对明文进行加密
for(int i=0; i<32;i++) {
s=s_he((strint[i+1]^strint[i+2]^strint[i+3]^key_kozhan[i]));
strint[i+4]=strint[i]^s^yiwei(s,2)^yiwei(s,10)^yiwei(s,18)^yiwei(s,24);
}
//倒序输出密文
System.out.println('\n'+"密文为 ");
for(int i=35;i>=32;i--) {
System.out.print(strint[i]+" ");
}
}
//将4个8位的Byte合并为一个32位的
static int kozhan(byte a,byte b,byte c,byte d) {
int e=0;
e=(a<<24|b<<16|c<<8|d);
return e;
}
//密钥扩展
static int[] key_kozhan(int a[]) {
int key_rk[]=new int[32];//存放的32轮密钥
//4个常数
int fk[]= {0xa3b1bac6,0x56aa3350,0x677d9197,0xb27022dc};
//32个固定参数
int ck[]= {
0x00070e15,0x1c232a31,0x383f464d,0x545b6269,
0x70777e85,0x8c939aa1,0xa8afb6bd,0xc4cbd2d9,
0xe0e7eef5,0xfc030a11,0x181f262d,0x343b4249,
0x50575e65,0x6c737a81,0x888f969d,0xa4abb2b9,
0xc0c7ced5,0xdce3eaf1,0xf8ff060d,0x141b2229,
0x30373e45,0x4c535a61,0x686f767d,0x848b9299,
0xa0a7aeb5,0xbcc3cad1,0xd8dfe6ed,0xf4fb0209,
0x10171e25,0x2c333a41,0x484f565d,0x646b7279
};
int s=0;
int b[]=new int[36];
for(int q=0;q<4;q++) {
b[q]=a[q]^fk[q];
}
for(int i=0;i<32;i++) {
s=s_he((b[i+1]^b[i+2]^b[i+3]^ck[i]));
key_rk[i]=b[i]^s^yiwei(s,13)^yiwei(s,23);
b[i+4]=key_rk[i];
}
return key_rk;
};
//移位操作，b为移动的位数
static int yiwei(int a,int b) {
a=(byte)((a>>32-b)|(a<<b));
return a;
}
//s盒变换
static int s_he(int a) {
//s盒的参数
int s[][]={
{0xd6,0x90,0xe9,0xfe,0xcc,0xe1,0x3d,0xb7,0x16,0xb6,0x14,0xc2,0x28,0xfb,0x2c,0x05},
{0x2b,0x67,0x9a,0x76,0x2a,0xbe,0x04,0xc3,0xaa,0x44,0x13,0x26,0x49,0x86,0x06,0x99},
{0x9c,0x42,0x50,0xf4,0x91,0xef,0x98,0x7a,0x33,0x54,0x0b,0x43,0xed,0xcf,0xac,0x62},
{0xe4,0xb3,0x1c,0xa9,0xc9,0x08,0xe8,0x95,0x80,0xdf,0x94,0xfa,0x75,0x8f,0x3f,0xa6},
{0x47,0x07,0xa7,0xfc,0xf3,0x73,0x17,0xba,0x83,0x59,0x3c,0x19,0xe6,0x85,0x4f,0xa8},
{0x68,0x6b,0x81,0xb2,0x71,0x64,0xda,0x8b,0xf8,0xeb,0x0f,0x4b,0x70,0x56,0x9d,0x35},
{0x1e,0x24,0x0e,0x5e,0x63,0x58,0xd1,0xa2,0x25,0x22,0x7c,0x3b,0x01,0x21,0x78,0x87},
{0xd4,0x00,0x46,0x57,0x9f,0xd3,0x27,0x52,0x4c,0x36,0x02,0xe7,0xa0,0xc4,0xc8,0x9e},
{0xea,0xbf,0x8a,0xd2,0x40,0xc7,0x38,0xb5,0xa3,0xf7,0xf2,0xce,0xf9,0x61,0x15,0xa1},
{0xe0,0xae,0x5d,0xa4,0x9b,0x34,0x1a,0x55,0xad,0x93,0x32,0x30,0xf5,0x8c,0xb1,0xe3},
{0x1d,0xf6,0xe2,0x2e,0x82,0x66,0xca,0x60,0xc0,0x29,0x23,0xab,0x0d,0x53,0x4e,0x6f},
{0xd5,0xdb,0x37,0x45,0xde,0xfd,0x8e,0x2f,0x03,0xff,0x6a,0x72,0x6d,0x6c,0x5b,0x51},
{0x8d,0x1b,0xaf,0x92,0xbb,0xdd,0xbc,0x7f,0x11,0xd9,0x5c,0x41,0x1f,0x10,0x5a,0xd8},
{0x0a,0xc1,0x31,0x88,0xa5,0xcd,0x7b,0xbd,0x2d,0x74,0xd0,0x12,0xb8,0xe5,0xb4,0xb0},
{0x89,0x69,0x97,0x4a,0x0c,0x96,0x77,0x7e,0x65,0xb9,0xf1,0x09,0xc5,0x6e,0xc6,0x84},
{0x18,0xf0,0x7d,0xec,0x3a,0xdc,0x4d,0x20,0x79,0xee,0x5f,0x3e,0xd7,0xcb,0x39,0x48}
};
byte b[]=new byte [4];
int c[]=new int[8];
//将32位分成8个4位的数
c[0]=(a&0xf0000000)>>28;
c[1]=(a&0x0f000000)>>24;
c[2]=(a&0x00f00000)>>20;
c[3]=(a&0x000f0000)>>16;
c[4]=(a&0x0000f000)>>12;
c[5]=(a&0x00000f00)>>8;
c[6]=(a&0x000000f0)>>4;
c[7]=a&0x0000000f;
//java中Int为带符号的32位，可能为负，将负值转换为正值
for(int i=0;i<8;i++) {
if(c[i]<0) {
c[i]=(int) Math.sqrt(c[i]*c[i]);
}
}
//变换操作
b[0]=(byte)s[c[0]][c[1]];
b[1]=(byte)s[c[2]][c[3]];
b[2]=(byte)s[c[4]][c[5]];
b[3]=(byte)s[c[6]][c[7]];
//将4个8位字节合并为一个字
a=(b[0]<<24|b[1]<<16|b[2]<<8|b[3]);
return a;
}
}
解密
package sm4;
import java.util.Scanner;
public class sm4de {
public static void main(String[] args) {
int strint[]=new int[36];
int s=0;
int key_int[]=new int[16];
int key_kozhan[]=new int[32];
char mingwen[]=new char[16];
Scanner in = new Scanner(System.in);
System.out.println("请输入密文 ");
for(int i=0;i<4;i++) {
strint[i] = in.nextInt();//获得输入的密文
}
System.out.println("请输入密钥 ");
for(int i=0;i<4;i++) {
key_int[i] = in.nextInt();//获得输入的密钥
}
//密钥扩展
key_kozhan=key_kozhan(key_int);
//对明文进行解密
for(int i=0; i<32;i++) {
s=s_he((strint[i+1]^strint[i+2]^strint[i+3]^key_kozhan[31-i]));
strint[i+4]=strint[i]^s^yiwei(s,2)^yiwei(s,10)^yiwei(s,18)^yiwei(s,24);
}
//倒序输出明文
System.out.println("明文为 ");
for(int i=35;i>=32;i--) {
mingwen=shuchu(strint[i]);
for(int j=0;j<4;j++) {
System.out.print(mingwen[j]);
}
}
}
//将4个8位的Byte合并为一个32位的
static int kozhan(byte a,byte b,byte c,byte d) {
int e=0;
e=(a<<24|b<<16|c<<8|d);
return e;
}
//密钥扩展
static int[] key_kozhan(int a[]) {
int key_rk[]=new int[32];//存放的32轮密钥
//4个常数
int fk[]= {0xa3b1bac6,0x56aa3350,0x677d9197,0xb27022dc};
//32个固定参数
int ck[]= {
0x00070e15,0x1c232a31,0x383f464d,0x545b6269,
0x70777e85,0x8c939aa1,0xa8afb6bd,0xc4cbd2d9,
0xe0e7eef5,0xfc030a11,0x181f262d,0x343b4249,
0x50575e65,0x6c737a81,0x888f969d,0xa4abb2b9,
0xc0c7ced5,0xdce3eaf1,0xf8ff060d,0x141b2229,
0x30373e45,0x4c535a61,0x686f767d,0x848b9299,
0xa0a7aeb5,0xbcc3cad1,0xd8dfe6ed,0xf4fb0209,
0x10171e25,0x2c333a41,0x484f565d,0x646b7279
};
int s=0;
int b[]=new int[36];
for(int q=0;q<4;q++) {
b[q]=a[q]^fk[q];
}
for(int i=0;i<32;i++) {
s=s_he((b[i+1]^b[i+2]^b[i+3]^ck[i]));
key_rk[i]=b[i]^s^yiwei(s,13)^yiwei(s,23);
b[i+4]=key_rk[i];
}
return key_rk;
};
//移位操作，b为移动的位数
static int yiwei(int a,int b) {
a=(byte)((a>>32-b)|(a<<b));
return a;
}
//s盒变换
static int s_he(int a) {
//s盒的参数
int s[][]={
{0xd6,0x90,0xe9,0xfe,0xcc,0xe1,0x3d,0xb7,0x16,0xb6,0x14,0xc2,0x28,0xfb,0x2c,0x05},
{0x2b,0x67,0x9a,0x76,0x2a,0xbe,0x04,0xc3,0xaa,0x44,0x13,0x26,0x49,0x86,0x06,0x99},
{0x9c,0x42,0x50,0xf4,0x91,0xef,0x98,0x7a,0x33,0x54,0x0b,0x43,0xed,0xcf,0xac,0x62},
{0xe4,0xb3,0x1c,0xa9,0xc9,0x08,0xe8,0x95,0x80,0xdf,0x94,0xfa,0x75,0x8f,0x3f,0xa6},
{0x47,0x07,0xa7,0xfc,0xf3,0x73,0x17,0xba,0x83,0x59,0x3c,0x19,0xe6,0x85,0x4f,0xa8},
{0x68,0x6b,0x81,0xb2,0x71,0x64,0xda,0x8b,0xf8,0xeb,0x0f,0x4b,0x70,0x56,0x9d,0x35},
{0x1e,0x24,0x0e,0x5e,0x63,0x58,0xd1,0xa2,0x25,0x22,0x7c,0x3b,0x01,0x21,0x78,0x87},
{0xd4,0x00,0x46,0x57,0x9f,0xd3,0x27,0x52,0x4c,0x36,0x02,0xe7,0xa0,0xc4,0xc8,0x9e},
{0xea,0xbf,0x8a,0xd2,0x40,0xc7,0x38,0xb5,0xa3,0xf7,0xf2,0xce,0xf9,0x61,0x15,0xa1},
{0xe0,0xae,0x5d,0xa4,0x9b,0x34,0x1a,0x55,0xad,0x93,0x32,0x30,0xf5,0x8c,0xb1,0xe3},
{0x1d,0xf6,0xe2,0x2e,0x82,0x66,0xca,0x60,0xc0,0x29,0x23,0xab,0x0d,0x53,0x4e,0x6f},
{0xd5,0xdb,0x37,0x45,0xde,0xfd,0x8e,0x2f,0x03,0xff,0x6a,0x72,0x6d,0x6c,0x5b,0x51},
{0x8d,0x1b,0xaf,0x92,0xbb,0xdd,0xbc,0x7f,0x11,0xd9,0x5c,0x41,0x1f,0x10,0x5a,0xd8},
{0x0a,0xc1,0x31,0x88,0xa5,0xcd,0x7b,0xbd,0x2d,0x74,0xd0,0x12,0xb8,0xe5,0xb4,0xb0},
{0x89,0x69,0x97,0x4a,0x0c,0x96,0x77,0x7e,0x65,0xb9,0xf1,0x09,0xc5,0x6e,0xc6,0x84},
{0x18,0xf0,0x7d,0xec,0x3a,0xdc,0x4d,0x20,0x79,0xee,0x5f,0x3e,0xd7,0xcb,0x39,0x48}
};
byte b[]=new byte [4];
int c[]=new int[8];
//将32位分成8个4位的数
c[0]=(a&0xf0000000)>>28;
c[1]=(a&0x0f000000)>>24;
c[2]=(a&0x00f00000)>>20;
c[3]=(a&0x000f0000)>>16;
c[4]=(a&0x0000f000)>>12;
c[5]=(a&0x00000f00)>>8;
c[6]=(a&0x000000f0)>>4;
c[7]=a&0x0000000f;
//java中Int为带符号的32位，可能为负，将负值转换为正值
for(int i=0;i<8;i++) {
if(c[i]<0) {
c[i]=(int) Math.sqrt(c[i]*c[i]);
}
}
//变换操作
b[0]=(byte)s[c[0]][c[1]];
b[1]=(byte)s[c[2]][c[3]];
b[2]=(byte)s[c[4]][c[5]];
b[3]=(byte)s[c[6]][c[7]];
//将4个8位字节合并为一个字
a=(b[0]<<24|b[1]<<16|b[2]<<8|b[3]);
return a;
}
static char[] shuchu(int a){
char b[]=new char[4];
b[0]=(char) ((a&0xff000000)>>24);
b[1]=(char) ((a&0x00ff0000)>>16);
b[2]=(char) ((a&0x0000ff00)>>8);
b[3]=(char)(a&0x000000ff);
return b;
}
}
运行效果
