rc4.txt

密码学RC4

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/rc4.h>

char *usage[]={
"usage: rc4 args\n",
"\n",
" -in arg         - input file - default stdin\n",
" -out arg        - output file - default stdout\n",
" -key key        - password\n",
NULL
};

int main(int argc, char *argv[])
        {
        FILE *in=NULL,*out=NULL;
        char *infile=NULL,*outfile=NULL,*keystr=NULL;
        RC4_KEY key;
        char buf[BUFSIZ];
        int badops=0,i;
        char **pp;
        unsigned char md[MD5_DIGEST_LENGTH];

        argc--;
        argv++;
        while (argc >= 1)
                {
                if      (strcmp(*argv,"-in") == 0)
                        {
                        if (--argc < 1) goto bad;
                        infile= *(++argv);
                        }
                else if (strcmp(*argv,"-out") == 0)
                        {
                        if (--argc < 1) goto bad;
                        outfile= *(++argv);
                        }
                else if (strcmp(*argv,"-key") == 0)
                        {
                        if (--argc < 1) goto bad;
                        keystr= *(++argv);
                        }
                else
                        {
                        fprintf(stderr,"unknown option %s\n",*argv);
                        badops=1;
                        break;
                        }
                argc--;
                argv++;
                }

        if (badops)
                {
bad:
                for (pp=usage; (*pp != NULL); pp++)
                        fprintf(stderr,"%s",*pp);
                exit(1);
                }

        if (infile == NULL)
                in=stdin;
        else
                {
                in=fopen(infile,"r");
                if (in == NULL)
                        {
                        perror("open");
                        exit(1);
                        }

                }
        if (outfile == NULL)
                out=stdout;
        else
                {
                out=fopen(outfile,"w");
                if (out == NULL)
                        {
                        perror("open");
                        exit(1);
                        }
                }

#ifdef OPENSSL_SYS_MSDOS
        /* This should set the file to binary mode. */
        {
#include <fcntl.h>
        setmode(fileno(in),O_BINARY);
        setmode(fileno(out),O_BINARY);
        }
#endif

        if (keystr == NULL)
                { /* get key */
                i=EVP_read_pw_string(buf,BUFSIZ,"Enter RC4 password:",0);
                if (i != 0)
                        {
                        OPENSSL_cleanse(buf,BUFSIZ);
                        fprintf(stderr,"bad password read\n");
                        exit(1);
                        }
                keystr=buf;
                }

        EVP_Digest((unsigned char *)keystr,(unsigned long)strlen(keystr),md,NULL,EVP_md5());
        OPENSSL_cleanse(keystr,strlen(keystr));
        RC4_set_key(&key,MD5_DIGEST_LENGTH,md);

        for(;;)
                {
                i=fread(buf,1,BUFSIZ,in);
                if (i == 0) break;
                if (i < 0)
                        {
                        perror("read");
                        exit(1);
                        }
                RC4(&key,(unsigned int)i,(unsigned char *)buf,
                        (unsigned char *)buf);
                i=fwrite(buf,(unsigned int)i,1,out);
                if (i != 1)
                        {
                        perror("write");
                        exit(1);
                        }
                }
        fclose(out);
        fclose(in);
        exit(0);
        return(1);
        }