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Secure Hash Algorithm (SHA-1) Reference implementation in C/C++

niyazpk wrote 11 months ago

The SHA-1 source code in C/C++ is given below. Download this source code from our download section. This html file may contain errors due to markup.

(Click here to go to the SHA-1 main page)

/*
******************************************************************
This source code is under development. Even though you can use it as
such, it is recommended you check back after a few days for an updated
version. The current version lacks descriptive comments also. 
******************************************************************
*/
 
 
#include<stdio.h>
#include<string.h>
#include<malloc.h>
#include<math.h>
#include<stdlib.h>
 
#define rotateleft(x,n) ((x<<n) | (x>>(32-n)))
#define rotateright(x,n) ((x>>n) | (x<<(32-n)))
 
void SHA1(unsigned char * str1)
{
	unsigned long int h0,h1,h2,h3,h4,a,b,c,d,e,f,k,temp;
 
	h0 = 0x67452301;
	h1 = 0xEFCDAB89;
	h2 = 0x98BADCFE;
	h3 = 0x10325476;
	h4 = 0xC3D2E1F0;
 
	unsigned char * str;
	str = (unsigned char *)malloc(strlen((const char *)str1)+100);
	strcpy((char *)str,(const char *)str1);
 
	int current_length = strlen((const char *)str);
	int original_length = current_length;
	str[current_length] = 0x80;
	str[current_length + 1] = '\0';
 
	char ic = str[current_length];
	current_length++;
 
	int ib = current_length % 64;
	if(ib<56)
		ib = 56-ib;
	else
		ib = 120 - ib;
 
	for(int i=0;i < ib;i++)
	{
		str[current_length]=0x00;
		current_length++;
	}
	str[current_length + 1]='\0';
 
	for(i=0;i<6;i++)
	{
		str[current_length]=0x0;
		current_length++;
	}
	str[current_length] = (original_length * 8) / 0x100 ;
	current_length++;
	str[current_length] = (original_length * 8) % 0x100;
	current_length++;
	str[current_length+i]='\0';
 
	int number_of_chunks = current_length/64;
	unsigned long int word[80];
	for(i=0;i<number_of_chunks;i++)
	{
		for(int j=0;j<16;j++)
		{
			word[j] = str[i*64 + j*4 + 0] * 0x1000000 + str[i*64 + j*4 + 1] * 0x10000 + str[i*64 + j*4 + 2] * 0x100 + str[i*64 + j*4 + 3];
		}
		for(j=16;j<80;j++)
		{
			word[j] = rotateleft((word[j-3] ^ word[j-8] ^ word[j-14] ^ word[j-16]),1);
		}
 
		a = h0;
		b = h1;
		c = h2;
		d = h3;
		e = h4;
 
		for(int m=0;m<80;m++)
		{
			if(m<=19)
			{
				f = (b & c) | ((~b) & d);
				k = 0x5A827999;
			}
			else if(m<=39)
			{
				f = b ^ c ^ d;
				k = 0x6ED9EBA1;
			}
			else if(m<=59)
			{
				f = (b & c) | (b & d) | (c & d);
				k = 0x8F1BBCDC;
			}
			else
			{
				f = b ^ c ^ d;
				k = 0xCA62C1D6; 
			}
 
			temp = (rotateleft(a,5) + f + e + k + word[m]) & 0xFFFFFFFF;
			e = d;
			d = c;
			c = rotateleft(b,30);
			b = a;
			a = temp;
 
		}
 
		h0 = h0 + a;
		h1 = h1 + b;
		h2 = h2 + c;
		h3 = h3 + d;
		h4 = h4 + e;
 
	}
 
	printf("\n\n");
	printf("Hash: %x %x %x %x %x",h0, h1, h2, h3, h4);
	printf("\n\n");
}
 
void main()
{
	SHA1((unsigned char *)"The quick brown fox jumps over the lazy dog");
}

License:

 No license. You are free to use this as you like. Anyway if you use this source code, it would be nice if you could link back to us or give credit to the author. Lot of work has gone into the development of this work. Anyway, thank you for visiting.


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