pkcs_5_1.c

一些封装好的加密函数的源代码

/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [e-mail], http://libtomcrypt.org
 */
#include "tomcrypt.h"

/** 
   @file pkcs_5_1.c
   PKCS #5, Algorithm #1, Tom St Denis
*/
#ifdef PKCS_5
/**
   Execute PKCS #5 v1
   @param password         The password (or key)
   @param password_len     The length of the password (octet)
   @param salt             The salt (or nonce) which is 8 octets long
   @param iteration_count  The PKCS #5 v1 iteration count
   @param hash_idx         The index of the hash desired
   @param out              [out] The destination for this algorithm
   @param outlen           [in/out] The max size and resulting size of the algorithm output
   @return CRYPT_OK if successful
*/
int pkcs_5_alg1(const unsigned char *password, unsigned long password_len, 
                const unsigned char *salt, 
                int iteration_count,  int hash_idx,
                unsigned char *out,   unsigned long *outlen)
{
   int err;
   unsigned long x;
   hash_state    *md;
   unsigned char *buf;

   LTC_ARGCHK(password != NULL);
   LTC_ARGCHK(salt     != NULL);
   LTC_ARGCHK(out      != NULL);
   LTC_ARGCHK(outlen   != NULL);

   /* test hash IDX */
   if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
      return err;
   }

   /* allocate memory */
   md  = XMALLOC(sizeof(hash_state));
   buf = XMALLOC(MAXBLOCKSIZE);
   if (md == NULL || buf == NULL) {
      if (md != NULL) {
         XFREE(md);
      }
      if (buf != NULL) { 
         XFREE(buf);
      }
      return CRYPT_MEM;
   }        

   /* hash initial password + salt */
   if ((err = hash_descriptor[hash_idx].init(md)) != CRYPT_OK) {
       goto LBL_ERR;
   }
   if ((err = hash_descriptor[hash_idx].process(md, password, password_len)) != CRYPT_OK) {
       goto LBL_ERR;
   }
   if ((err = hash_descriptor[hash_idx].process(md, salt, 8)) != CRYPT_OK) {
       goto LBL_ERR;
   }
   if ((err = hash_descriptor[hash_idx].done(md, buf)) != CRYPT_OK) {
       goto LBL_ERR;
   }

   while (--iteration_count) {
      /* code goes here. */
      x = MAXBLOCKSIZE;
      if ((err = hash_memory(hash_idx, buf, hash_descriptor[hash_idx].hashsize, buf, &x)) != CRYPT_OK) {
         goto LBL_ERR;
      }
   }

   /* copy upto outlen bytes */
   for (x = 0; x < hash_descriptor[hash_idx].hashsize && x < *outlen; x++) {
       out[x] = buf[x];
   }
   *outlen = x;
   err = CRYPT_OK;
LBL_ERR:
#ifdef LTC_CLEAN_STACK 
   zeromem(buf, MAXBLOCKSIZE);
   zeromem(md, sizeof(hash_state));
#endif

   XFREE(buf);
   XFREE(md);

   return err;
}

int  main(void) 
{ 
      unsigned    char  password[100],        salt[100], 
                         cipher_key[16],  cipher_iv[16], 
                         mac_key[16],      outbuf[48]; 
      int                err,  hash_idx,i; 
      unsigned    long   outlen,  password_len,j; 
    /*  register  hash and  get it’s idx .... */ 
	/* register   SHA-1  */ 
    if (register_hash(&sha1_desc)  ==     -1)  { 
       printf("Error   registering   SHA1\n"); 
       return  -1; 
    } 

    /* get  index  of SHA1  in  hash descriptor   table  */ 
    hash_idx  = find_hash("sha1"); 

    /*  get users  password  and  make up a salt  ... */ 
	for( i=0;i<100;i++){
		password[i]=i;
		printf("%x,",password[i]);
	}
	password_len=i;
	for( i=0;i<100;i++){
		salt[i]=i;
	}
    /*  create  the  material (100  iterations  in  algorithm)  */ 
    outlen  = sizeof(outbuf); 
    if  ((err =  pkcs_5_alg1(password,  password_len,    salt,  
                              100,  hash_idx,  outbuf,  &outlen))  != CRYPT_OK)  { 
        /* error  handle  */ 
    } 

    /*  now extract  it */ 
    memcpy(cipher_key,  outbuf,   16); 
    memcpy(cipher_iv,    outbuf+16,   16); 
    memcpy(mac_key,      outbuf+32,   16);


	printf("outbuf            \n\n");
	for(j=0;j<outlen;j++){
		printf("%x,",outbuf[j]);
	}
	printf("\n outlen=%d",outlen);
    /*  use material  (recall to  store  the salt  in  the output)  */ 
	return 1;
} 


#endif

/* $Source: /cvs/libtom/libtomcrypt/src/misc/pkcs5/pkcs_5_1.c,v $ */
/* $Revision: 1.4 $ */
/* $Date: 2005/05/05 14:35:59 $ */