md5 checksum of string

md5sum-1.c

#include <stdio.h>
#include <openssl/md5.h>
int main(int argc,char *argv[]){
  MD5_CTX c;
  FILE *f;
  unsigned char b[1024];
  unsigned char md[MD5_LBLOCK];
  size_t n;
  int i;
  if(argc!=2){
    printf("Usage: md5 filename\n");
    return 1;
  }
  MD5_Init(&c);
  if((f=fopen(argv[1],"rb"))==NULL){
    printf("Error: file open error\n");
    return 1;
  }
  while((n=fread(b,sizeof(char),1024,f))>0){
    MD5_Update(&c,b,n);
  }
  MD5_Final(md,&c);
  for(i=0;i<16;i++) printf("%02x",md[i]);
  printf("\t%s\n",argv[1]);
  fclose(f);
  return 0;
}

md5sum-2.c

#include <stdio.h>
#include <openssl/md5.h>
int main(int argc,char *argv[]){
  FILE *f; 
  unsigned char b[1024*1024];
  unsigned char md[]={
    0x67,0x45,0x23,0x01,0xef,0xcd,0xab,0x89,
    0x98,0xba,0xdc,0xfe,0x10,0x32,0x54,0x76 };
  size_t n;
  int i;
  if(argc!=2){
    printf("Usage: md5 filename\n");
    return 1;
  }
  if((f=fopen(argv[1],"rb"))==NULL){
    printf("Error: file open error\n");
    return 1;
  }
  if((n=fread(b,sizeof(char),1024*1024,f))>0){
    MD5(b,n,md);
  }
  for(i=0;i<16;i++) printf("%02x",md[i]);
  printf("\t%s\n",argv[1]);
  fclose(f);
  return 0;
}