SHA的简介
美国国家标准技术研究所NIST于1993年开发的另一个散
列算法称为SHA。两年之后，这个算法被修改为了今天广泛
使用的形式。修改后的版本是SHA-1，是数字签名标准中要
求使用的算法。
SHA接受任何有限长度的输入消息，并产生长度为160比
特的Hash值（MD5仅仅生成128位的摘要），因此抗穷举性
更好。SHA-1设计时基于和MD4相同原理，它有5个参与运
算的32位寄存器字，消息分组和填充方式与MD5相同，主循
环也同样是4轮，但每轮进行20次操作，非线性运算、移位和
加法运算也与MD5类似，但非线性函数、加法常数和循环左
移操作的设计有一些区别。
SHA-1哈希值的生成过程
SHA-1对单个512位分组的处理过程
SHA-1生成字Wt的方法
SHA-1的基本操作
C语言实现
#include <stdio.h>
#include <string.h>
#include "sha1.h"
#define S(x,n) (((x)<<n)|(x)>>(32-n)) //SHA定义S函数为循环左移
static unsigned long h[5];
static unsigned long m[16];
static unsigned long w[80];
//补位(余数=448)+补长度(64位)=512位M
static void sha1_pad( char *input, int len)
{
int i;
int n;
for(i=0;i<16;i++)
{
m[i] = 0;
}
//printf("%d",len);
for(i=0;i<len;i++)
{
n = 24-((i&0x03)<<3);
m[i/4] |= input[i]<<n;
}
n = 24-((i&0x03)<<3);
m[i/4] |= 0x80<<n;
m[15] = len*8;
}
//由512位M生成80字W
static void sha1_prepare(void)
{
int i;
for(i=0;i<16;i++)
{
w[i]=m[i];
}
for(i=16;i<80;i++)
{
w[i]=w[i-16]^w[i-14]^w[i-8]^w[i-3];
w[i]=S(w[i],1);
}
}
//由80字W计算sha1
static void sha1_calc(void)
{
int i;
unsigned long a,b,c,d,e,f,k;
unsigned long temp;
h[0]=0x67452301;
h[1]=0xEFCDAB89;
h[2]=0x98BADCFE;
h[3]=0x10325476;
h[4]=0xC3D2E1F0;
a = h[0];
b = h[1];
c = h[2];
d = h[3];
e = h[4];
for(i=0;i<80;i++)
{
switch(i/20)
{
case 0:
k=0x5A827999;
f=(b&c)|(~b&d);
break;
case 1:
k=0x6ED9EBA1;
f=b^c^d;
break;
case 2:
k=0x8F1BBCDC;
f=(b&c)|(b&d)|(c&d);
break;
case 3:
k=0xCA62C1D6;
f=b^c^d;
break;
}
temp=S(a,5)+f+e+w[i]+k;
e=d;
d=c;
c=S(b,30);
b=a;
a=temp;
}
h[0]+=a;
h[1]+=b;
h[2]+=c;
h[3]+=d;
h[4]+=e;
}
//SHA1算法接口
//input:待校验的数据
//len:数据长度(小于56字节)
unsigned long* sha1( char* input, int len)
{
sha1_pad(input,len);
sha1_prepare();
sha1_calc();
return h;
}
main()
{
char str[1024];
unsigned long* mac;
while(1)
{
puts("input:");
gets(str);
mac=sha1(str,strlen(str));
printf("SHA1=%08X%08X%08X%08X%08X\n",mac[0],mac[1],mac[2],mac[3],mac[4]);
//system("pause");
}
}
//sha1.h：对字符串进行sha1加密
#include <string.h>
#include <stdio.h>
#ifndef _SHA1_H_
#define _SHA1_H_
typedef struct SHA1Context{
unsigned Message_Digest[5];
unsigned Length_Low;
unsigned Length_High;
unsigned char Message_Block[64];
int Message_Block_Index;
int Computed;
int Corrupted;
} SHA1Context;
void SHA1Reset(SHA1Context *);
int SHA1Result(SHA1Context *);
void SHA1Input( SHA1Context *,const char *,unsigned);
#endif
#define SHA1CircularShift(bits,word) ((((word) << (bits)) & 0xFFFFFFFF) | ((word) >> (32-(bits))))
void SHA1ProcessMessageBlock(SHA1Context *);
void SHA1PadMessage(SHA1Context *);
void SHA1Reset(SHA1Context *context){
// 初始化动作
context->Length_Low = 0;
context->Length_High = 0;
context->Message_Block_Index = 0;
context->Message_Digest[0] = 0x67452301;
context->Message_Digest[1] = 0xEFCDAB89;
context->Message_Digest[2] = 0x98BADCFE;
context->Message_Digest[3] = 0x10325476;
context->Message_Digest[4] = 0xC3D2E1F0;
context->Computed = 0;
context->Corrupted = 0;
}
int SHA1Result(SHA1Context *context){
// 成功返回1，失败返回0
if (context->Corrupted) {
return 0;
}
if (!context->Computed) {
SHA1PadMessage(context);
context->Computed = 1;
}
return 1;
}
void SHA1Input(SHA1Context *context,const char *message_array,unsigned length){
if (!length) return;
if (context->Computed || context->Corrupted){
context->Corrupted = 1;
return;
}
while(length-- && !context->Corrupted){
context->Message_Block[context->Message_Block_Index++] = (*message_array & 0xFF);
context->Length_Low += 8;
context->Length_Low &= 0xFFFFFFFF;
if (context->Length_Low == 0){
context->Length_High++;
context->Length_High &= 0xFFFFFFFF;
if (context->Length_High == 0) context->Corrupted = 1;
}
if (context->Message_Block_Index == 64){
SHA1ProcessMessageBlock(context);
}
message_array++;
}
}
void SHA1ProcessMessageBlock(SHA1Context *context){
const unsigned K[] = {
0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6 };
int t;
unsigned temp;
unsigned W[80];
unsigned A, B, C, D, E;
for(t = 0; t < 16; t++) {
W[t] = ((unsigned) context->Message_Block[t * 4]) << 24;
W[t] |= ((unsigned) context->Message_Block[t * 4 + 1]) << 16;
W[t] |= ((unsigned) context->Message_Block[t * 4 + 2]) << 8;
W[t] |= ((unsigned) context->Message_Block[t * 4 + 3]);
}
for(t = 16; t < 80; t++) W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
A = context->Message_Digest[0];
B = context->Message_Digest[1];
C = context->Message_Digest[2];
D = context->Message_Digest[3];
E = context->Message_Digest[4];
for(t = 0; t < 20; t++) {
temp = SHA1CircularShift(5,A) + ((B & C) | ((~B) & D)) + E + W[t] + K[0];
temp &= 0xFFFFFFFF;
E = D;
D = C;
C = SHA1CircularShift(30,B);
B = A;
A = temp;
}
for(t = 20; t < 40; t++) {
temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
temp &= 0xFFFFFFFF;
E = D;
D = C;
C = SHA1CircularShift(30,B);
B = A;
A = temp;
}
for(t = 40; t < 60; t++) {
temp = SHA1CircularShift(5,A) + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
temp &= 0xFFFFFFFF;
E = D;
D = C;
C = SHA1CircularShift(30,B);
B = A;
A = temp;
}
for(t = 60; t < 80; t++) {
temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
temp &= 0xFFFFFFFF;
E = D;
D = C;
C = SHA1CircularShift(30,B);
B = A;
A = temp;
}
context->Message_Digest[0] = (context->Message_Digest[0] + A) & 0xFFFFFFFF;
context->Message_Digest[1] = (context->Message_Digest[1] + B) & 0xFFFFFFFF;
context->Message_Digest[2] = (context->Message_Digest[2] + C) & 0xFFFFFFFF;
context->Message_Digest[3] = (context->Message_Digest[3] + D) & 0xFFFFFFFF;
context->Message_Digest[4] = (context->Message_Digest[4] + E) & 0xFFFFFFFF;
context->Message_Block_Index = 0;
}
void SHA1PadMessage(SHA1Context *context){
if (context->Message_Block_Index > 55) {
context->Message_Block[context->Message_Block_Index++] = 0x80;
while(context->Message_Block_Index < 64) context->Message_Block[context->Message_Block_Index++] = 0;
SHA1ProcessMessageBlock(context);
while(context->Message_Block_Index < 56) context->Message_Block[context->Message_Block_Index++] = 0;
} else {
context->Message_Block[context->Message_Block_Index++] = 0x80;
while(context->Message_Block_Index < 56) context->Message_Block[context->Message_Block_Index++] = 0;
}
context->Message_Block[56] = (context->Length_High >> 24 ) & 0xFF;
context->Message_Block[57] = (context->Length_High >> 16 ) & 0xFF;
context->Message_Block[58] = (context->Length_High >> 8 ) & 0xFF;
context->Message_Block[59] = (context->Length_High) & 0xFF;
context->Message_Block[60] = (context->Length_Low >> 24 ) & 0xFF;
context->Message_Block[61] = (context->Length_Low >> 16 ) & 0xFF;
context->Message_Block[62] = (context->Length_Low >> 8 ) & 0xFF;
context->Message_Block[63] = (context->Length_Low) & 0xFF;
SHA1ProcessMessageBlock(context);
}
int sha1_hash(const char *source, char *lrvar){
// Main
SHA1Context sha;
char buf[128];
SHA1Reset(&sha);
SHA1Input(&sha, source, strlen(source));
if (!SHA1Result(&sha)){
// lr_error_message("SHA1 ERROR: Could not compute message digest");
return -1;
} else {
memset(buf,0,sizeof(buf));
sprintf(buf, "%08X%08X%08X%08X%08X", sha.Message_Digest[0],sha.Message_Digest[1],
sha.Message_Digest[2],sha.Message_Digest[3],sha.Message_Digest[4]);
//lr_save_string(buf, lrvar);
return strlen(buf);
}
}